| /* |
| * Generic hugetlb support. |
| * (C) Nadia Yvette Chambers, April 2004 |
| */ |
| #include <linux/list.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/seq_file.h> |
| #include <linux/sysctl.h> |
| #include <linux/highmem.h> |
| #include <linux/mmu_notifier.h> |
| #include <linux/nodemask.h> |
| #include <linux/pagemap.h> |
| #include <linux/mempolicy.h> |
| #include <linux/compiler.h> |
| #include <linux/cpuset.h> |
| #include <linux/mutex.h> |
| #include <linux/bootmem.h> |
| #include <linux/sysfs.h> |
| #include <linux/slab.h> |
| #include <linux/mmdebug.h> |
| #include <linux/sched/signal.h> |
| #include <linux/rmap.h> |
| #include <linux/string_helpers.h> |
| #include <linux/swap.h> |
| #include <linux/swapops.h> |
| #include <linux/jhash.h> |
| |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| #include <asm/tlb.h> |
| |
| #include <linux/io.h> |
| #include <linux/hugetlb.h> |
| #include <linux/hugetlb_cgroup.h> |
| #include <linux/node.h> |
| #include <linux/userfaultfd_k.h> |
| #include "internal.h" |
| |
| int hugepages_treat_as_movable; |
| |
| int hugetlb_max_hstate __read_mostly; |
| unsigned int default_hstate_idx; |
| struct hstate hstates[HUGE_MAX_HSTATE]; |
| /* |
| * Minimum page order among possible hugepage sizes, set to a proper value |
| * at boot time. |
| */ |
| static unsigned int minimum_order __read_mostly = UINT_MAX; |
| |
| __initdata LIST_HEAD(huge_boot_pages); |
| |
| /* for command line parsing */ |
| static struct hstate * __initdata parsed_hstate; |
| static unsigned long __initdata default_hstate_max_huge_pages; |
| static unsigned long __initdata default_hstate_size; |
| static bool __initdata parsed_valid_hugepagesz = true; |
| |
| /* |
| * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, |
| * free_huge_pages, and surplus_huge_pages. |
| */ |
| DEFINE_SPINLOCK(hugetlb_lock); |
| |
| /* |
| * Serializes faults on the same logical page. This is used to |
| * prevent spurious OOMs when the hugepage pool is fully utilized. |
| */ |
| static int num_fault_mutexes; |
| struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; |
| |
| static inline bool PageHugeFreed(struct page *head) |
| { |
| return page_private(head + 4) == -1UL; |
| } |
| |
| static inline void SetPageHugeFreed(struct page *head) |
| { |
| set_page_private(head + 4, -1UL); |
| } |
| |
| static inline void ClearPageHugeFreed(struct page *head) |
| { |
| set_page_private(head + 4, 0); |
| } |
| |
| /* Forward declaration */ |
| static int hugetlb_acct_memory(struct hstate *h, long delta); |
| |
| static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) |
| { |
| bool free = (spool->count == 0) && (spool->used_hpages == 0); |
| |
| spin_unlock(&spool->lock); |
| |
| /* If no pages are used, and no other handles to the subpool |
| * remain, give up any reservations mased on minimum size and |
| * free the subpool */ |
| if (free) { |
| if (spool->min_hpages != -1) |
| hugetlb_acct_memory(spool->hstate, |
| -spool->min_hpages); |
| kfree(spool); |
| } |
| } |
| |
| struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages, |
| long min_hpages) |
| { |
| struct hugepage_subpool *spool; |
| |
| spool = kzalloc(sizeof(*spool), GFP_KERNEL); |
| if (!spool) |
| return NULL; |
| |
| spin_lock_init(&spool->lock); |
| spool->count = 1; |
| spool->max_hpages = max_hpages; |
| spool->hstate = h; |
| spool->min_hpages = min_hpages; |
| |
| if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) { |
| kfree(spool); |
| return NULL; |
| } |
| spool->rsv_hpages = min_hpages; |
| |
| return spool; |
| } |
| |
| void hugepage_put_subpool(struct hugepage_subpool *spool) |
| { |
| spin_lock(&spool->lock); |
| BUG_ON(!spool->count); |
| spool->count--; |
| unlock_or_release_subpool(spool); |
| } |
| |
| /* |
| * Subpool accounting for allocating and reserving pages. |
| * Return -ENOMEM if there are not enough resources to satisfy the |
| * the request. Otherwise, return the number of pages by which the |
| * global pools must be adjusted (upward). The returned value may |
| * only be different than the passed value (delta) in the case where |
| * a subpool minimum size must be manitained. |
| */ |
| static long hugepage_subpool_get_pages(struct hugepage_subpool *spool, |
| long delta) |
| { |
| long ret = delta; |
| |
| if (!spool) |
| return ret; |
| |
| spin_lock(&spool->lock); |
| |
| if (spool->max_hpages != -1) { /* maximum size accounting */ |
| if ((spool->used_hpages + delta) <= spool->max_hpages) |
| spool->used_hpages += delta; |
| else { |
| ret = -ENOMEM; |
| goto unlock_ret; |
| } |
| } |
| |
| /* minimum size accounting */ |
| if (spool->min_hpages != -1 && spool->rsv_hpages) { |
| if (delta > spool->rsv_hpages) { |
| /* |
| * Asking for more reserves than those already taken on |
| * behalf of subpool. Return difference. |
| */ |
| ret = delta - spool->rsv_hpages; |
| spool->rsv_hpages = 0; |
| } else { |
| ret = 0; /* reserves already accounted for */ |
| spool->rsv_hpages -= delta; |
| } |
| } |
| |
| unlock_ret: |
| spin_unlock(&spool->lock); |
| return ret; |
| } |
| |
| /* |
| * Subpool accounting for freeing and unreserving pages. |
| * Return the number of global page reservations that must be dropped. |
| * The return value may only be different than the passed value (delta) |
| * in the case where a subpool minimum size must be maintained. |
| */ |
| static long hugepage_subpool_put_pages(struct hugepage_subpool *spool, |
| long delta) |
| { |
| long ret = delta; |
| |
| if (!spool) |
| return delta; |
| |
| spin_lock(&spool->lock); |
| |
| if (spool->max_hpages != -1) /* maximum size accounting */ |
| spool->used_hpages -= delta; |
| |
| /* minimum size accounting */ |
| if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) { |
| if (spool->rsv_hpages + delta <= spool->min_hpages) |
| ret = 0; |
| else |
| ret = spool->rsv_hpages + delta - spool->min_hpages; |
| |
| spool->rsv_hpages += delta; |
| if (spool->rsv_hpages > spool->min_hpages) |
| spool->rsv_hpages = spool->min_hpages; |
| } |
| |
| /* |
| * If hugetlbfs_put_super couldn't free spool due to an outstanding |
| * quota reference, free it now. |
| */ |
| unlock_or_release_subpool(spool); |
| |
| return ret; |
| } |
| |
| static inline struct hugepage_subpool *subpool_inode(struct inode *inode) |
| { |
| return HUGETLBFS_SB(inode->i_sb)->spool; |
| } |
| |
| static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) |
| { |
| return subpool_inode(file_inode(vma->vm_file)); |
| } |
| |
| /* |
| * Region tracking -- allows tracking of reservations and instantiated pages |
| * across the pages in a mapping. |
| * |
| * The region data structures are embedded into a resv_map and protected |
| * by a resv_map's lock. The set of regions within the resv_map represent |
| * reservations for huge pages, or huge pages that have already been |
| * instantiated within the map. The from and to elements are huge page |
| * indicies into the associated mapping. from indicates the starting index |
| * of the region. to represents the first index past the end of the region. |
| * |
| * For example, a file region structure with from == 0 and to == 4 represents |
| * four huge pages in a mapping. It is important to note that the to element |
| * represents the first element past the end of the region. This is used in |
| * arithmetic as 4(to) - 0(from) = 4 huge pages in the region. |
| * |
| * Interval notation of the form [from, to) will be used to indicate that |
| * the endpoint from is inclusive and to is exclusive. |
| */ |
| struct file_region { |
| struct list_head link; |
| long from; |
| long to; |
| }; |
| |
| /* |
| * Add the huge page range represented by [f, t) to the reserve |
| * map. In the normal case, existing regions will be expanded |
| * to accommodate the specified range. Sufficient regions should |
| * exist for expansion due to the previous call to region_chg |
| * with the same range. However, it is possible that region_del |
| * could have been called after region_chg and modifed the map |
| * in such a way that no region exists to be expanded. In this |
| * case, pull a region descriptor from the cache associated with |
| * the map and use that for the new range. |
| * |
| * Return the number of new huge pages added to the map. This |
| * number is greater than or equal to zero. |
| */ |
| static long region_add(struct resv_map *resv, long f, long t) |
| { |
| struct list_head *head = &resv->regions; |
| struct file_region *rg, *nrg, *trg; |
| long add = 0; |
| |
| spin_lock(&resv->lock); |
| /* Locate the region we are either in or before. */ |
| list_for_each_entry(rg, head, link) |
| if (f <= rg->to) |
| break; |
| |
| /* |
| * If no region exists which can be expanded to include the |
| * specified range, the list must have been modified by an |
| * interleving call to region_del(). Pull a region descriptor |
| * from the cache and use it for this range. |
| */ |
| if (&rg->link == head || t < rg->from) { |
| VM_BUG_ON(resv->region_cache_count <= 0); |
| |
| resv->region_cache_count--; |
| nrg = list_first_entry(&resv->region_cache, struct file_region, |
| link); |
| list_del(&nrg->link); |
| |
| nrg->from = f; |
| nrg->to = t; |
| list_add(&nrg->link, rg->link.prev); |
| |
| add += t - f; |
| goto out_locked; |
| } |
| |
| /* Round our left edge to the current segment if it encloses us. */ |
| if (f > rg->from) |
| f = rg->from; |
| |
| /* Check for and consume any regions we now overlap with. */ |
| nrg = rg; |
| list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| if (rg->from > t) |
| break; |
| |
| /* If this area reaches higher then extend our area to |
| * include it completely. If this is not the first area |
| * which we intend to reuse, free it. */ |
| if (rg->to > t) |
| t = rg->to; |
| if (rg != nrg) { |
| /* Decrement return value by the deleted range. |
| * Another range will span this area so that by |
| * end of routine add will be >= zero |
| */ |
| add -= (rg->to - rg->from); |
| list_del(&rg->link); |
| kfree(rg); |
| } |
| } |
| |
| add += (nrg->from - f); /* Added to beginning of region */ |
| nrg->from = f; |
| add += t - nrg->to; /* Added to end of region */ |
| nrg->to = t; |
| |
| out_locked: |
| resv->adds_in_progress--; |
| spin_unlock(&resv->lock); |
| VM_BUG_ON(add < 0); |
| return add; |
| } |
| |
| /* |
| * Examine the existing reserve map and determine how many |
| * huge pages in the specified range [f, t) are NOT currently |
| * represented. This routine is called before a subsequent |
| * call to region_add that will actually modify the reserve |
| * map to add the specified range [f, t). region_chg does |
| * not change the number of huge pages represented by the |
| * map. However, if the existing regions in the map can not |
| * be expanded to represent the new range, a new file_region |
| * structure is added to the map as a placeholder. This is |
| * so that the subsequent region_add call will have all the |
| * regions it needs and will not fail. |
| * |
| * Upon entry, region_chg will also examine the cache of region descriptors |
| * associated with the map. If there are not enough descriptors cached, one |
| * will be allocated for the in progress add operation. |
| * |
| * Returns the number of huge pages that need to be added to the existing |
| * reservation map for the range [f, t). This number is greater or equal to |
| * zero. -ENOMEM is returned if a new file_region structure or cache entry |
| * is needed and can not be allocated. |
| */ |
| static long region_chg(struct resv_map *resv, long f, long t) |
| { |
| struct list_head *head = &resv->regions; |
| struct file_region *rg, *nrg = NULL; |
| long chg = 0; |
| |
| retry: |
| spin_lock(&resv->lock); |
| retry_locked: |
| resv->adds_in_progress++; |
| |
| /* |
| * Check for sufficient descriptors in the cache to accommodate |
| * the number of in progress add operations. |
| */ |
| if (resv->adds_in_progress > resv->region_cache_count) { |
| struct file_region *trg; |
| |
| VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1); |
| /* Must drop lock to allocate a new descriptor. */ |
| resv->adds_in_progress--; |
| spin_unlock(&resv->lock); |
| |
| trg = kmalloc(sizeof(*trg), GFP_KERNEL); |
| if (!trg) { |
| kfree(nrg); |
| return -ENOMEM; |
| } |
| |
| spin_lock(&resv->lock); |
| list_add(&trg->link, &resv->region_cache); |
| resv->region_cache_count++; |
| goto retry_locked; |
| } |
| |
| /* Locate the region we are before or in. */ |
| list_for_each_entry(rg, head, link) |
| if (f <= rg->to) |
| break; |
| |
| /* If we are below the current region then a new region is required. |
| * Subtle, allocate a new region at the position but make it zero |
| * size such that we can guarantee to record the reservation. */ |
| if (&rg->link == head || t < rg->from) { |
| if (!nrg) { |
| resv->adds_in_progress--; |
| spin_unlock(&resv->lock); |
| nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| if (!nrg) |
| return -ENOMEM; |
| |
| nrg->from = f; |
| nrg->to = f; |
| INIT_LIST_HEAD(&nrg->link); |
| goto retry; |
| } |
| |
| list_add(&nrg->link, rg->link.prev); |
| chg = t - f; |
| goto out_nrg; |
| } |
| |
| /* Round our left edge to the current segment if it encloses us. */ |
| if (f > rg->from) |
| f = rg->from; |
| chg = t - f; |
| |
| /* Check for and consume any regions we now overlap with. */ |
| list_for_each_entry(rg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| if (rg->from > t) |
| goto out; |
| |
| /* We overlap with this area, if it extends further than |
| * us then we must extend ourselves. Account for its |
| * existing reservation. */ |
| if (rg->to > t) { |
| chg += rg->to - t; |
| t = rg->to; |
| } |
| chg -= rg->to - rg->from; |
| } |
| |
| out: |
| spin_unlock(&resv->lock); |
| /* We already know we raced and no longer need the new region */ |
| kfree(nrg); |
| return chg; |
| out_nrg: |
| spin_unlock(&resv->lock); |
| return chg; |
| } |
| |
| /* |
| * Abort the in progress add operation. The adds_in_progress field |
| * of the resv_map keeps track of the operations in progress between |
| * calls to region_chg and region_add. Operations are sometimes |
| * aborted after the call to region_chg. In such cases, region_abort |
| * is called to decrement the adds_in_progress counter. |
| * |
| * NOTE: The range arguments [f, t) are not needed or used in this |
| * routine. They are kept to make reading the calling code easier as |
| * arguments will match the associated region_chg call. |
| */ |
| static void region_abort(struct resv_map *resv, long f, long t) |
| { |
| spin_lock(&resv->lock); |
| VM_BUG_ON(!resv->region_cache_count); |
| resv->adds_in_progress--; |
| spin_unlock(&resv->lock); |
| } |
| |
| /* |
| * Delete the specified range [f, t) from the reserve map. If the |
| * t parameter is LONG_MAX, this indicates that ALL regions after f |
| * should be deleted. Locate the regions which intersect [f, t) |
| * and either trim, delete or split the existing regions. |
| * |
| * Returns the number of huge pages deleted from the reserve map. |
| * In the normal case, the return value is zero or more. In the |
| * case where a region must be split, a new region descriptor must |
| * be allocated. If the allocation fails, -ENOMEM will be returned. |
| * NOTE: If the parameter t == LONG_MAX, then we will never split |
| * a region and possibly return -ENOMEM. Callers specifying |
| * t == LONG_MAX do not need to check for -ENOMEM error. |
| */ |
| static long region_del(struct resv_map *resv, long f, long t) |
| { |
| struct list_head *head = &resv->regions; |
| struct file_region *rg, *trg; |
| struct file_region *nrg = NULL; |
| long del = 0; |
| |
| retry: |
| spin_lock(&resv->lock); |
| list_for_each_entry_safe(rg, trg, head, link) { |
| /* |
| * Skip regions before the range to be deleted. file_region |
| * ranges are normally of the form [from, to). However, there |
| * may be a "placeholder" entry in the map which is of the form |
| * (from, to) with from == to. Check for placeholder entries |
| * at the beginning of the range to be deleted. |
| */ |
| if (rg->to <= f && (rg->to != rg->from || rg->to != f)) |
| continue; |
| |
| if (rg->from >= t) |
| break; |
| |
| if (f > rg->from && t < rg->to) { /* Must split region */ |
| /* |
| * Check for an entry in the cache before dropping |
| * lock and attempting allocation. |
| */ |
| if (!nrg && |
| resv->region_cache_count > resv->adds_in_progress) { |
| nrg = list_first_entry(&resv->region_cache, |
| struct file_region, |
| link); |
| list_del(&nrg->link); |
| resv->region_cache_count--; |
| } |
| |
| if (!nrg) { |
| spin_unlock(&resv->lock); |
| nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| if (!nrg) |
| return -ENOMEM; |
| goto retry; |
| } |
| |
| del += t - f; |
| |
| /* New entry for end of split region */ |
| nrg->from = t; |
| nrg->to = rg->to; |
| INIT_LIST_HEAD(&nrg->link); |
| |
| /* Original entry is trimmed */ |
| rg->to = f; |
| |
| list_add(&nrg->link, &rg->link); |
| nrg = NULL; |
| break; |
| } |
| |
| if (f <= rg->from && t >= rg->to) { /* Remove entire region */ |
| del += rg->to - rg->from; |
| list_del(&rg->link); |
| kfree(rg); |
| continue; |
| } |
| |
| if (f <= rg->from) { /* Trim beginning of region */ |
| del += t - rg->from; |
| rg->from = t; |
| } else { /* Trim end of region */ |
| del += rg->to - f; |
| rg->to = f; |
| } |
| } |
| |
| spin_unlock(&resv->lock); |
| kfree(nrg); |
| return del; |
| } |
| |
| /* |
| * A rare out of memory error was encountered which prevented removal of |
| * the reserve map region for a page. The huge page itself was free'ed |
| * and removed from the page cache. This routine will adjust the subpool |
| * usage count, and the global reserve count if needed. By incrementing |
| * these counts, the reserve map entry which could not be deleted will |
| * appear as a "reserved" entry instead of simply dangling with incorrect |
| * counts. |
| */ |
| void hugetlb_fix_reserve_counts(struct inode *inode) |
| { |
| struct hugepage_subpool *spool = subpool_inode(inode); |
| long rsv_adjust; |
| bool reserved = false; |
| |
| rsv_adjust = hugepage_subpool_get_pages(spool, 1); |
| if (rsv_adjust > 0) { |
| struct hstate *h = hstate_inode(inode); |
| |
| if (!hugetlb_acct_memory(h, 1)) |
| reserved = true; |
| } else if (!rsv_adjust) { |
| reserved = true; |
| } |
| |
| if (!reserved) |
| pr_warn("hugetlb: Huge Page Reserved count may go negative.\n"); |
| } |
| |
| /* |
| * Count and return the number of huge pages in the reserve map |
| * that intersect with the range [f, t). |
| */ |
| static long region_count(struct resv_map *resv, long f, long t) |
| { |
| struct list_head *head = &resv->regions; |
| struct file_region *rg; |
| long chg = 0; |
| |
| spin_lock(&resv->lock); |
| /* Locate each segment we overlap with, and count that overlap. */ |
| list_for_each_entry(rg, head, link) { |
| long seg_from; |
| long seg_to; |
| |
| if (rg->to <= f) |
| continue; |
| if (rg->from >= t) |
| break; |
| |
| seg_from = max(rg->from, f); |
| seg_to = min(rg->to, t); |
| |
| chg += seg_to - seg_from; |
| } |
| spin_unlock(&resv->lock); |
| |
| return chg; |
| } |
| |
| /* |
| * Convert the address within this vma to the page offset within |
| * the mapping, in pagecache page units; huge pages here. |
| */ |
| static pgoff_t vma_hugecache_offset(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address) |
| { |
| return ((address - vma->vm_start) >> huge_page_shift(h)) + |
| (vma->vm_pgoff >> huge_page_order(h)); |
| } |
| |
| pgoff_t linear_hugepage_index(struct vm_area_struct *vma, |
| unsigned long address) |
| { |
| return vma_hugecache_offset(hstate_vma(vma), vma, address); |
| } |
| EXPORT_SYMBOL_GPL(linear_hugepage_index); |
| |
| /* |
| * Return the size of the pages allocated when backing a VMA. In the majority |
| * cases this will be same size as used by the page table entries. |
| */ |
| unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) |
| { |
| struct hstate *hstate; |
| |
| if (!is_vm_hugetlb_page(vma)) |
| return PAGE_SIZE; |
| |
| hstate = hstate_vma(vma); |
| |
| return 1UL << huge_page_shift(hstate); |
| } |
| EXPORT_SYMBOL_GPL(vma_kernel_pagesize); |
| |
| /* |
| * Return the page size being used by the MMU to back a VMA. In the majority |
| * of cases, the page size used by the kernel matches the MMU size. On |
| * architectures where it differs, an architecture-specific version of this |
| * function is required. |
| */ |
| #ifndef vma_mmu_pagesize |
| unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) |
| { |
| return vma_kernel_pagesize(vma); |
| } |
| #endif |
| |
| /* |
| * Flags for MAP_PRIVATE reservations. These are stored in the bottom |
| * bits of the reservation map pointer, which are always clear due to |
| * alignment. |
| */ |
| #define HPAGE_RESV_OWNER (1UL << 0) |
| #define HPAGE_RESV_UNMAPPED (1UL << 1) |
| #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
| |
| /* |
| * These helpers are used to track how many pages are reserved for |
| * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
| * is guaranteed to have their future faults succeed. |
| * |
| * With the exception of reset_vma_resv_huge_pages() which is called at fork(), |
| * the reserve counters are updated with the hugetlb_lock held. It is safe |
| * to reset the VMA at fork() time as it is not in use yet and there is no |
| * chance of the global counters getting corrupted as a result of the values. |
| * |
| * The private mapping reservation is represented in a subtly different |
| * manner to a shared mapping. A shared mapping has a region map associated |
| * with the underlying file, this region map represents the backing file |
| * pages which have ever had a reservation assigned which this persists even |
| * after the page is instantiated. A private mapping has a region map |
| * associated with the original mmap which is attached to all VMAs which |
| * reference it, this region map represents those offsets which have consumed |
| * reservation ie. where pages have been instantiated. |
| */ |
| static unsigned long get_vma_private_data(struct vm_area_struct *vma) |
| { |
| return (unsigned long)vma->vm_private_data; |
| } |
| |
| static void set_vma_private_data(struct vm_area_struct *vma, |
| unsigned long value) |
| { |
| vma->vm_private_data = (void *)value; |
| } |
| |
| struct resv_map *resv_map_alloc(void) |
| { |
| struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); |
| struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL); |
| |
| if (!resv_map || !rg) { |
| kfree(resv_map); |
| kfree(rg); |
| return NULL; |
| } |
| |
| kref_init(&resv_map->refs); |
| spin_lock_init(&resv_map->lock); |
| INIT_LIST_HEAD(&resv_map->regions); |
| |
| resv_map->adds_in_progress = 0; |
| |
| INIT_LIST_HEAD(&resv_map->region_cache); |
| list_add(&rg->link, &resv_map->region_cache); |
| resv_map->region_cache_count = 1; |
| |
| return resv_map; |
| } |
| |
| void resv_map_release(struct kref *ref) |
| { |
| struct resv_map *resv_map = container_of(ref, struct resv_map, refs); |
| struct list_head *head = &resv_map->region_cache; |
| struct file_region *rg, *trg; |
| |
| /* Clear out any active regions before we release the map. */ |
| region_del(resv_map, 0, LONG_MAX); |
| |
| /* ... and any entries left in the cache */ |
| list_for_each_entry_safe(rg, trg, head, link) { |
| list_del(&rg->link); |
| kfree(rg); |
| } |
| |
| VM_BUG_ON(resv_map->adds_in_progress); |
| |
| kfree(resv_map); |
| } |
| |
| static inline struct resv_map *inode_resv_map(struct inode *inode) |
| { |
| return inode->i_mapping->private_data; |
| } |
| |
| static struct resv_map *vma_resv_map(struct vm_area_struct *vma) |
| { |
| VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| if (vma->vm_flags & VM_MAYSHARE) { |
| struct address_space *mapping = vma->vm_file->f_mapping; |
| struct inode *inode = mapping->host; |
| |
| return inode_resv_map(inode); |
| |
| } else { |
| return (struct resv_map *)(get_vma_private_data(vma) & |
| ~HPAGE_RESV_MASK); |
| } |
| } |
| |
| static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) |
| { |
| VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma); |
| |
| set_vma_private_data(vma, (get_vma_private_data(vma) & |
| HPAGE_RESV_MASK) | (unsigned long)map); |
| } |
| |
| static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) |
| { |
| VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma); |
| |
| set_vma_private_data(vma, get_vma_private_data(vma) | flags); |
| } |
| |
| static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
| { |
| VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| |
| return (get_vma_private_data(vma) & flag) != 0; |
| } |
| |
| /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ |
| void reset_vma_resv_huge_pages(struct vm_area_struct *vma) |
| { |
| VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| if (!(vma->vm_flags & VM_MAYSHARE)) |
| vma->vm_private_data = (void *)0; |
| } |
| |
| /* Returns true if the VMA has associated reserve pages */ |
| static bool vma_has_reserves(struct vm_area_struct *vma, long chg) |
| { |
| if (vma->vm_flags & VM_NORESERVE) { |
| /* |
| * This address is already reserved by other process(chg == 0), |
| * so, we should decrement reserved count. Without decrementing, |
| * reserve count remains after releasing inode, because this |
| * allocated page will go into page cache and is regarded as |
| * coming from reserved pool in releasing step. Currently, we |
| * don't have any other solution to deal with this situation |
| * properly, so add work-around here. |
| */ |
| if (vma->vm_flags & VM_MAYSHARE && chg == 0) |
| return true; |
| else |
| return false; |
| } |
| |
| /* Shared mappings always use reserves */ |
| if (vma->vm_flags & VM_MAYSHARE) { |
| /* |
| * We know VM_NORESERVE is not set. Therefore, there SHOULD |
| * be a region map for all pages. The only situation where |
| * there is no region map is if a hole was punched via |
| * fallocate. In this case, there really are no reverves to |
| * use. This situation is indicated if chg != 0. |
| */ |
| if (chg) |
| return false; |
| else |
| return true; |
| } |
| |
| /* |
| * Only the process that called mmap() has reserves for |
| * private mappings. |
| */ |
| if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| /* |
| * Like the shared case above, a hole punch or truncate |
| * could have been performed on the private mapping. |
| * Examine the value of chg to determine if reserves |
| * actually exist or were previously consumed. |
| * Very Subtle - The value of chg comes from a previous |
| * call to vma_needs_reserves(). The reserve map for |
| * private mappings has different (opposite) semantics |
| * than that of shared mappings. vma_needs_reserves() |
| * has already taken this difference in semantics into |
| * account. Therefore, the meaning of chg is the same |
| * as in the shared case above. Code could easily be |
| * combined, but keeping it separate draws attention to |
| * subtle differences. |
| */ |
| if (chg) |
| return false; |
| else |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static void enqueue_huge_page(struct hstate *h, struct page *page) |
| { |
| int nid = page_to_nid(page); |
| list_move(&page->lru, &h->hugepage_freelists[nid]); |
| h->free_huge_pages++; |
| h->free_huge_pages_node[nid]++; |
| SetPageHugeFreed(page); |
| } |
| |
| static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) |
| { |
| struct page *page; |
| |
| list_for_each_entry(page, &h->hugepage_freelists[nid], lru) |
| if (!PageHWPoison(page)) |
| break; |
| /* |
| * if 'non-isolated free hugepage' not found on the list, |
| * the allocation fails. |
| */ |
| if (&h->hugepage_freelists[nid] == &page->lru) |
| return NULL; |
| list_move(&page->lru, &h->hugepage_activelist); |
| set_page_refcounted(page); |
| ClearPageHugeFreed(page); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[nid]--; |
| return page; |
| } |
| |
| static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid, |
| nodemask_t *nmask) |
| { |
| unsigned int cpuset_mems_cookie; |
| struct zonelist *zonelist; |
| struct zone *zone; |
| struct zoneref *z; |
| int node = -1; |
| |
| zonelist = node_zonelist(nid, gfp_mask); |
| |
| retry_cpuset: |
| cpuset_mems_cookie = read_mems_allowed_begin(); |
| for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) { |
| struct page *page; |
| |
| if (!cpuset_zone_allowed(zone, gfp_mask)) |
| continue; |
| /* |
| * no need to ask again on the same node. Pool is node rather than |
| * zone aware |
| */ |
| if (zone_to_nid(zone) == node) |
| continue; |
| node = zone_to_nid(zone); |
| |
| page = dequeue_huge_page_node_exact(h, node); |
| if (page) |
| return page; |
| } |
| if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie))) |
| goto retry_cpuset; |
| |
| return NULL; |
| } |
| |
| /* Movability of hugepages depends on migration support. */ |
| static inline gfp_t htlb_alloc_mask(struct hstate *h) |
| { |
| if (hugepages_treat_as_movable || hugepage_migration_supported(h)) |
| return GFP_HIGHUSER_MOVABLE; |
| else |
| return GFP_HIGHUSER; |
| } |
| |
| static struct page *dequeue_huge_page_vma(struct hstate *h, |
| struct vm_area_struct *vma, |
| unsigned long address, int avoid_reserve, |
| long chg) |
| { |
| struct page *page; |
| struct mempolicy *mpol; |
| gfp_t gfp_mask; |
| nodemask_t *nodemask; |
| int nid; |
| |
| /* |
| * A child process with MAP_PRIVATE mappings created by their parent |
| * have no page reserves. This check ensures that reservations are |
| * not "stolen". The child may still get SIGKILLed |
| */ |
| if (!vma_has_reserves(vma, chg) && |
| h->free_huge_pages - h->resv_huge_pages == 0) |
| goto err; |
| |
| /* If reserves cannot be used, ensure enough pages are in the pool */ |
| if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) |
| goto err; |
| |
| gfp_mask = htlb_alloc_mask(h); |
| nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask); |
| page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); |
| if (page && !avoid_reserve && vma_has_reserves(vma, chg)) { |
| SetPagePrivate(page); |
| h->resv_huge_pages--; |
| } |
| |
| mpol_cond_put(mpol); |
| return page; |
| |
| err: |
| return NULL; |
| } |
| |
| /* |
| * common helper functions for hstate_next_node_to_{alloc|free}. |
| * We may have allocated or freed a huge page based on a different |
| * nodes_allowed previously, so h->next_node_to_{alloc|free} might |
| * be outside of *nodes_allowed. Ensure that we use an allowed |
| * node for alloc or free. |
| */ |
| static int next_node_allowed(int nid, nodemask_t *nodes_allowed) |
| { |
| nid = next_node_in(nid, *nodes_allowed); |
| VM_BUG_ON(nid >= MAX_NUMNODES); |
| |
| return nid; |
| } |
| |
| static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) |
| { |
| if (!node_isset(nid, *nodes_allowed)) |
| nid = next_node_allowed(nid, nodes_allowed); |
| return nid; |
| } |
| |
| /* |
| * returns the previously saved node ["this node"] from which to |
| * allocate a persistent huge page for the pool and advance the |
| * next node from which to allocate, handling wrap at end of node |
| * mask. |
| */ |
| static int hstate_next_node_to_alloc(struct hstate *h, |
| nodemask_t *nodes_allowed) |
| { |
| int nid; |
| |
| VM_BUG_ON(!nodes_allowed); |
| |
| nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); |
| h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); |
| |
| return nid; |
| } |
| |
| /* |
| * helper for free_pool_huge_page() - return the previously saved |
| * node ["this node"] from which to free a huge page. Advance the |
| * next node id whether or not we find a free huge page to free so |
| * that the next attempt to free addresses the next node. |
| */ |
| static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) |
| { |
| int nid; |
| |
| VM_BUG_ON(!nodes_allowed); |
| |
| nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); |
| h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); |
| |
| return nid; |
| } |
| |
| #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ |
| for (nr_nodes = nodes_weight(*mask); \ |
| nr_nodes > 0 && \ |
| ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ |
| nr_nodes--) |
| |
| #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ |
| for (nr_nodes = nodes_weight(*mask); \ |
| nr_nodes > 0 && \ |
| ((node = hstate_next_node_to_free(hs, mask)) || 1); \ |
| nr_nodes--) |
| |
| #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE |
| static void destroy_compound_gigantic_page(struct page *page, |
| unsigned int order) |
| { |
| int i; |
| int nr_pages = 1 << order; |
| struct page *p = page + 1; |
| |
| atomic_set(compound_mapcount_ptr(page), 0); |
| for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
| clear_compound_head(p); |
| set_page_refcounted(p); |
| } |
| |
| set_compound_order(page, 0); |
| __ClearPageHead(page); |
| } |
| |
| static void free_gigantic_page(struct page *page, unsigned int order) |
| { |
| free_contig_range(page_to_pfn(page), 1 << order); |
| } |
| |
| static int __alloc_gigantic_page(unsigned long start_pfn, |
| unsigned long nr_pages, gfp_t gfp_mask) |
| { |
| unsigned long end_pfn = start_pfn + nr_pages; |
| return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, |
| gfp_mask); |
| } |
| |
| static bool pfn_range_valid_gigantic(struct zone *z, |
| unsigned long start_pfn, unsigned long nr_pages) |
| { |
| unsigned long i, end_pfn = start_pfn + nr_pages; |
| struct page *page; |
| |
| for (i = start_pfn; i < end_pfn; i++) { |
| page = pfn_to_online_page(i); |
| if (!page) |
| return false; |
| |
| if (page_zone(page) != z) |
| return false; |
| |
| if (PageReserved(page)) |
| return false; |
| |
| if (page_count(page) > 0) |
| return false; |
| |
| if (PageHuge(page)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| static bool zone_spans_last_pfn(const struct zone *zone, |
| unsigned long start_pfn, unsigned long nr_pages) |
| { |
| unsigned long last_pfn = start_pfn + nr_pages - 1; |
| return zone_spans_pfn(zone, last_pfn); |
| } |
| |
| static struct page *alloc_gigantic_page(int nid, struct hstate *h) |
| { |
| unsigned int order = huge_page_order(h); |
| unsigned long nr_pages = 1 << order; |
| unsigned long ret, pfn, flags; |
| struct zonelist *zonelist; |
| struct zone *zone; |
| struct zoneref *z; |
| gfp_t gfp_mask; |
| |
| gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
| zonelist = node_zonelist(nid, gfp_mask); |
| for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), NULL) { |
| spin_lock_irqsave(&zone->lock, flags); |
| |
| pfn = ALIGN(zone->zone_start_pfn, nr_pages); |
| while (zone_spans_last_pfn(zone, pfn, nr_pages)) { |
| if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) { |
| /* |
| * We release the zone lock here because |
| * alloc_contig_range() will also lock the zone |
| * at some point. If there's an allocation |
| * spinning on this lock, it may win the race |
| * and cause alloc_contig_range() to fail... |
| */ |
| spin_unlock_irqrestore(&zone->lock, flags); |
| ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask); |
| if (!ret) |
| return pfn_to_page(pfn); |
| spin_lock_irqsave(&zone->lock, flags); |
| } |
| pfn += nr_pages; |
| } |
| |
| spin_unlock_irqrestore(&zone->lock, flags); |
| } |
| |
| return NULL; |
| } |
| |
| static void prep_new_huge_page(struct hstate *h, struct page *page, int nid); |
| static void prep_compound_gigantic_page(struct page *page, unsigned int order); |
| |
| static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid) |
| { |
| struct page *page; |
| |
| page = alloc_gigantic_page(nid, h); |
| if (page) { |
| prep_compound_gigantic_page(page, huge_page_order(h)); |
| prep_new_huge_page(h, page, nid); |
| } |
| |
| return page; |
| } |
| |
| static int alloc_fresh_gigantic_page(struct hstate *h, |
| nodemask_t *nodes_allowed) |
| { |
| struct page *page = NULL; |
| int nr_nodes, node; |
| |
| for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
| page = alloc_fresh_gigantic_page_node(h, node); |
| if (page) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */ |
| static inline bool gigantic_page_supported(void) { return false; } |
| static inline void free_gigantic_page(struct page *page, unsigned int order) { } |
| static inline void destroy_compound_gigantic_page(struct page *page, |
| unsigned int order) { } |
| static inline int alloc_fresh_gigantic_page(struct hstate *h, |
| nodemask_t *nodes_allowed) { return 0; } |
| #endif |
| |
| static void update_and_free_page(struct hstate *h, struct page *page) |
| { |
| int i; |
| struct page *subpage = page; |
| |
| if (hstate_is_gigantic(h) && !gigantic_page_supported()) |
| return; |
| |
| h->nr_huge_pages--; |
| h->nr_huge_pages_node[page_to_nid(page)]--; |
| for (i = 0; i < pages_per_huge_page(h); |
| i++, subpage = mem_map_next(subpage, page, i)) { |
| subpage->flags &= ~(1 << PG_locked | 1 << PG_error | |
| 1 << PG_referenced | 1 << PG_dirty | |
| 1 << PG_active | 1 << PG_private | |
| 1 << PG_writeback); |
| } |
| VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); |
| set_compound_page_dtor(page, NULL_COMPOUND_DTOR); |
| set_page_refcounted(page); |
| if (hstate_is_gigantic(h)) { |
| destroy_compound_gigantic_page(page, huge_page_order(h)); |
| free_gigantic_page(page, huge_page_order(h)); |
| } else { |
| __free_pages(page, huge_page_order(h)); |
| } |
| } |
| |
| struct hstate *size_to_hstate(unsigned long size) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| if (huge_page_size(h) == size) |
| return h; |
| } |
| return NULL; |
| } |
| |
| /* |
| * Test to determine whether the hugepage is "active/in-use" (i.e. being linked |
| * to hstate->hugepage_activelist.) |
| * |
| * This function can be called for tail pages, but never returns true for them. |
| */ |
| bool page_huge_active(struct page *page) |
| { |
| return PageHeadHuge(page) && PagePrivate(&page[1]); |
| } |
| |
| /* never called for tail page */ |
| void set_page_huge_active(struct page *page) |
| { |
| VM_BUG_ON_PAGE(!PageHeadHuge(page), page); |
| SetPagePrivate(&page[1]); |
| } |
| |
| static void clear_page_huge_active(struct page *page) |
| { |
| VM_BUG_ON_PAGE(!PageHeadHuge(page), page); |
| ClearPagePrivate(&page[1]); |
| } |
| |
| void free_huge_page(struct page *page) |
| { |
| /* |
| * Can't pass hstate in here because it is called from the |
| * compound page destructor. |
| */ |
| struct hstate *h = page_hstate(page); |
| int nid = page_to_nid(page); |
| struct hugepage_subpool *spool = |
| (struct hugepage_subpool *)page_private(page); |
| bool restore_reserve; |
| |
| set_page_private(page, 0); |
| page->mapping = NULL; |
| VM_BUG_ON_PAGE(page_count(page), page); |
| VM_BUG_ON_PAGE(page_mapcount(page), page); |
| restore_reserve = PagePrivate(page); |
| ClearPagePrivate(page); |
| |
| /* |
| * If PagePrivate() was set on page, page allocation consumed a |
| * reservation. If the page was associated with a subpool, there |
| * would have been a page reserved in the subpool before allocation |
| * via hugepage_subpool_get_pages(). Since we are 'restoring' the |
| * reservtion, do not call hugepage_subpool_put_pages() as this will |
| * remove the reserved page from the subpool. |
| */ |
| if (!restore_reserve) { |
| /* |
| * A return code of zero implies that the subpool will be |
| * under its minimum size if the reservation is not restored |
| * after page is free. Therefore, force restore_reserve |
| * operation. |
| */ |
| if (hugepage_subpool_put_pages(spool, 1) == 0) |
| restore_reserve = true; |
| } |
| |
| spin_lock(&hugetlb_lock); |
| clear_page_huge_active(page); |
| hugetlb_cgroup_uncharge_page(hstate_index(h), |
| pages_per_huge_page(h), page); |
| if (restore_reserve) |
| h->resv_huge_pages++; |
| |
| if (h->surplus_huge_pages_node[nid]) { |
| /* remove the page from active list */ |
| list_del(&page->lru); |
| update_and_free_page(h, page); |
| h->surplus_huge_pages--; |
| h->surplus_huge_pages_node[nid]--; |
| } else { |
| arch_clear_hugepage_flags(page); |
| enqueue_huge_page(h, page); |
| } |
| spin_unlock(&hugetlb_lock); |
| } |
| |
| static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
| { |
| INIT_LIST_HEAD(&page->lru); |
| set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); |
| spin_lock(&hugetlb_lock); |
| set_hugetlb_cgroup(page, NULL); |
| h->nr_huge_pages++; |
| h->nr_huge_pages_node[nid]++; |
| ClearPageHugeFreed(page); |
| spin_unlock(&hugetlb_lock); |
| put_page(page); /* free it into the hugepage allocator */ |
| } |
| |
| static void prep_compound_gigantic_page(struct page *page, unsigned int order) |
| { |
| int i; |
| int nr_pages = 1 << order; |
| struct page *p = page + 1; |
| |
| /* we rely on prep_new_huge_page to set the destructor */ |
| set_compound_order(page, order); |
| __ClearPageReserved(page); |
| __SetPageHead(page); |
| for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { |
| /* |
| * For gigantic hugepages allocated through bootmem at |
| * boot, it's safer to be consistent with the not-gigantic |
| * hugepages and clear the PG_reserved bit from all tail pages |
| * too. Otherwse drivers using get_user_pages() to access tail |
| * pages may get the reference counting wrong if they see |
| * PG_reserved set on a tail page (despite the head page not |
| * having PG_reserved set). Enforcing this consistency between |
| * head and tail pages allows drivers to optimize away a check |
| * on the head page when they need know if put_page() is needed |
| * after get_user_pages(). |
| */ |
| __ClearPageReserved(p); |
| set_page_count(p, 0); |
| set_compound_head(p, page); |
| } |
| atomic_set(compound_mapcount_ptr(page), -1); |
| } |
| |
| /* |
| * PageHuge() only returns true for hugetlbfs pages, but not for normal or |
| * transparent huge pages. See the PageTransHuge() documentation for more |
| * details. |
| */ |
| int PageHuge(struct page *page) |
| { |
| if (!PageCompound(page)) |
| return 0; |
| |
| page = compound_head(page); |
| return page[1].compound_dtor == HUGETLB_PAGE_DTOR; |
| } |
| EXPORT_SYMBOL_GPL(PageHuge); |
| |
| /* |
| * PageHeadHuge() only returns true for hugetlbfs head page, but not for |
| * normal or transparent huge pages. |
| */ |
| int PageHeadHuge(struct page *page_head) |
| { |
| if (!PageHead(page_head)) |
| return 0; |
| |
| return get_compound_page_dtor(page_head) == free_huge_page; |
| } |
| |
| pgoff_t hugetlb_basepage_index(struct page *page) |
| { |
| struct page *page_head = compound_head(page); |
| pgoff_t index = page_index(page_head); |
| unsigned long compound_idx; |
| |
| if (compound_order(page_head) >= MAX_ORDER) |
| compound_idx = page_to_pfn(page) - page_to_pfn(page_head); |
| else |
| compound_idx = page - page_head; |
| |
| return (index << compound_order(page_head)) + compound_idx; |
| } |
| |
| static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) |
| { |
| struct page *page; |
| |
| page = __alloc_pages_node(nid, |
| htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| |
| __GFP_RETRY_MAYFAIL|__GFP_NOWARN, |
| huge_page_order(h)); |
| if (page) { |
| prep_new_huge_page(h, page, nid); |
| } |
| |
| return page; |
| } |
| |
| static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) |
| { |
| struct page *page; |
| int nr_nodes, node; |
| int ret = 0; |
| |
| for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
| page = alloc_fresh_huge_page_node(h, node); |
| if (page) { |
| ret = 1; |
| break; |
| } |
| } |
| |
| if (ret) |
| count_vm_event(HTLB_BUDDY_PGALLOC); |
| else |
| count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| |
| return ret; |
| } |
| |
| /* |
| * Free huge page from pool from next node to free. |
| * Attempt to keep persistent huge pages more or less |
| * balanced over allowed nodes. |
| * Called with hugetlb_lock locked. |
| */ |
| static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, |
| bool acct_surplus) |
| { |
| int nr_nodes, node; |
| int ret = 0; |
| |
| for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
| /* |
| * If we're returning unused surplus pages, only examine |
| * nodes with surplus pages. |
| */ |
| if ((!acct_surplus || h->surplus_huge_pages_node[node]) && |
| !list_empty(&h->hugepage_freelists[node])) { |
| struct page *page = |
| list_entry(h->hugepage_freelists[node].next, |
| struct page, lru); |
| list_del(&page->lru); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[node]--; |
| if (acct_surplus) { |
| h->surplus_huge_pages--; |
| h->surplus_huge_pages_node[node]--; |
| } |
| update_and_free_page(h, page); |
| ret = 1; |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Dissolve a given free hugepage into free buddy pages. This function does |
| * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the |
| * number of free hugepages would be reduced below the number of reserved |
| * hugepages. |
| */ |
| int dissolve_free_huge_page(struct page *page) |
| { |
| int rc = 0; |
| |
| retry: |
| spin_lock(&hugetlb_lock); |
| if (PageHuge(page) && !page_count(page)) { |
| struct page *head = compound_head(page); |
| struct hstate *h = page_hstate(head); |
| int nid = page_to_nid(head); |
| if (h->free_huge_pages - h->resv_huge_pages == 0) { |
| rc = -EBUSY; |
| goto out; |
| } |
| |
| /* |
| * We should make sure that the page is already on the free list |
| * when it is dissolved. |
| */ |
| if (unlikely(!PageHugeFreed(head))) { |
| spin_unlock(&hugetlb_lock); |
| cond_resched(); |
| |
| /* |
| * Theoretically, we should return -EBUSY when we |
| * encounter this race. In fact, we have a chance |
| * to successfully dissolve the page if we do a |
| * retry. Because the race window is quite small. |
| * If we seize this opportunity, it is an optimization |
| * for increasing the success rate of dissolving page. |
| */ |
| goto retry; |
| } |
| |
| /* |
| * Move PageHWPoison flag from head page to the raw error page, |
| * which makes any subpages rather than the error page reusable. |
| */ |
| if (PageHWPoison(head) && page != head) { |
| SetPageHWPoison(page); |
| ClearPageHWPoison(head); |
| } |
| list_del(&head->lru); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[nid]--; |
| h->max_huge_pages--; |
| update_and_free_page(h, head); |
| } |
| out: |
| spin_unlock(&hugetlb_lock); |
| return rc; |
| } |
| |
| /* |
| * Dissolve free hugepages in a given pfn range. Used by memory hotplug to |
| * make specified memory blocks removable from the system. |
| * Note that this will dissolve a free gigantic hugepage completely, if any |
| * part of it lies within the given range. |
| * Also note that if dissolve_free_huge_page() returns with an error, all |
| * free hugepages that were dissolved before that error are lost. |
| */ |
| int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) |
| { |
| unsigned long pfn; |
| struct page *page; |
| int rc = 0; |
| |
| if (!hugepages_supported()) |
| return rc; |
| |
| for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) { |
| page = pfn_to_page(pfn); |
| if (PageHuge(page) && !page_count(page)) { |
| rc = dissolve_free_huge_page(page); |
| if (rc) |
| break; |
| } |
| } |
| |
| return rc; |
| } |
| |
| static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h, |
| gfp_t gfp_mask, int nid, nodemask_t *nmask) |
| { |
| int order = huge_page_order(h); |
| |
| gfp_mask |= __GFP_COMP|__GFP_RETRY_MAYFAIL|__GFP_NOWARN; |
| if (nid == NUMA_NO_NODE) |
| nid = numa_mem_id(); |
| return __alloc_pages_nodemask(gfp_mask, order, nid, nmask); |
| } |
| |
| static struct page *__alloc_buddy_huge_page(struct hstate *h, gfp_t gfp_mask, |
| int nid, nodemask_t *nmask) |
| { |
| struct page *page; |
| unsigned int r_nid; |
| |
| if (hstate_is_gigantic(h)) |
| return NULL; |
| |
| /* |
| * Assume we will successfully allocate the surplus page to |
| * prevent racing processes from causing the surplus to exceed |
| * overcommit |
| * |
| * This however introduces a different race, where a process B |
| * tries to grow the static hugepage pool while alloc_pages() is |
| * called by process A. B will only examine the per-node |
| * counters in determining if surplus huge pages can be |
| * converted to normal huge pages in adjust_pool_surplus(). A |
| * won't be able to increment the per-node counter, until the |
| * lock is dropped by B, but B doesn't drop hugetlb_lock until |
| * no more huge pages can be converted from surplus to normal |
| * state (and doesn't try to convert again). Thus, we have a |
| * case where a surplus huge page exists, the pool is grown, and |
| * the surplus huge page still exists after, even though it |
| * should just have been converted to a normal huge page. This |
| * does not leak memory, though, as the hugepage will be freed |
| * once it is out of use. It also does not allow the counters to |
| * go out of whack in adjust_pool_surplus() as we don't modify |
| * the node values until we've gotten the hugepage and only the |
| * per-node value is checked there. |
| */ |
| spin_lock(&hugetlb_lock); |
| if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
| spin_unlock(&hugetlb_lock); |
| return NULL; |
| } else { |
| h->nr_huge_pages++; |
| h->surplus_huge_pages++; |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| page = __hugetlb_alloc_buddy_huge_page(h, gfp_mask, nid, nmask); |
| |
| spin_lock(&hugetlb_lock); |
| if (page) { |
| INIT_LIST_HEAD(&page->lru); |
| r_nid = page_to_nid(page); |
| set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); |
| set_hugetlb_cgroup(page, NULL); |
| /* |
| * We incremented the global counters already |
| */ |
| h->nr_huge_pages_node[r_nid]++; |
| h->surplus_huge_pages_node[r_nid]++; |
| __count_vm_event(HTLB_BUDDY_PGALLOC); |
| } else { |
| h->nr_huge_pages--; |
| h->surplus_huge_pages--; |
| __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| return page; |
| } |
| |
| /* |
| * Use the VMA's mpolicy to allocate a huge page from the buddy. |
| */ |
| static |
| struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| struct page *page; |
| struct mempolicy *mpol; |
| gfp_t gfp_mask = htlb_alloc_mask(h); |
| int nid; |
| nodemask_t *nodemask; |
| |
| nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask); |
| page = __alloc_buddy_huge_page(h, gfp_mask, nid, nodemask); |
| mpol_cond_put(mpol); |
| |
| return page; |
| } |
| |
| /* |
| * This allocation function is useful in the context where vma is irrelevant. |
| * E.g. soft-offlining uses this function because it only cares physical |
| * address of error page. |
| */ |
| struct page *alloc_huge_page_node(struct hstate *h, int nid) |
| { |
| gfp_t gfp_mask = htlb_alloc_mask(h); |
| struct page *page = NULL; |
| |
| if (nid != NUMA_NO_NODE) |
| gfp_mask |= __GFP_THISNODE; |
| |
| spin_lock(&hugetlb_lock); |
| if (h->free_huge_pages - h->resv_huge_pages > 0) |
| page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL); |
| spin_unlock(&hugetlb_lock); |
| |
| if (!page) |
| page = __alloc_buddy_huge_page(h, gfp_mask, nid, NULL); |
| |
| return page; |
| } |
| |
| |
| struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid, |
| nodemask_t *nmask) |
| { |
| gfp_t gfp_mask = htlb_alloc_mask(h); |
| |
| spin_lock(&hugetlb_lock); |
| if (h->free_huge_pages - h->resv_huge_pages > 0) { |
| struct page *page; |
| |
| page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask); |
| if (page) { |
| spin_unlock(&hugetlb_lock); |
| return page; |
| } |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| /* No reservations, try to overcommit */ |
| |
| return __alloc_buddy_huge_page(h, gfp_mask, preferred_nid, nmask); |
| } |
| |
| /* |
| * Increase the hugetlb pool such that it can accommodate a reservation |
| * of size 'delta'. |
| */ |
| static int gather_surplus_pages(struct hstate *h, int delta) |
| { |
| struct list_head surplus_list; |
| struct page *page, *tmp; |
| int ret, i; |
| int needed, allocated; |
| bool alloc_ok = true; |
| |
| needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
| if (needed <= 0) { |
| h->resv_huge_pages += delta; |
| return 0; |
| } |
| |
| allocated = 0; |
| INIT_LIST_HEAD(&surplus_list); |
| |
| ret = -ENOMEM; |
| retry: |
| spin_unlock(&hugetlb_lock); |
| for (i = 0; i < needed; i++) { |
| page = __alloc_buddy_huge_page(h, htlb_alloc_mask(h), |
| NUMA_NO_NODE, NULL); |
| if (!page) { |
| alloc_ok = false; |
| break; |
| } |
| list_add(&page->lru, &surplus_list); |
| cond_resched(); |
| } |
| allocated += i; |
| |
| /* |
| * After retaking hugetlb_lock, we need to recalculate 'needed' |
| * because either resv_huge_pages or free_huge_pages may have changed. |
| */ |
| spin_lock(&hugetlb_lock); |
| needed = (h->resv_huge_pages + delta) - |
| (h->free_huge_pages + allocated); |
| if (needed > 0) { |
| if (alloc_ok) |
| goto retry; |
| /* |
| * We were not able to allocate enough pages to |
| * satisfy the entire reservation so we free what |
| * we've allocated so far. |
| */ |
| goto free; |
| } |
| /* |
| * The surplus_list now contains _at_least_ the number of extra pages |
| * needed to accommodate the reservation. Add the appropriate number |
| * of pages to the hugetlb pool and free the extras back to the buddy |
| * allocator. Commit the entire reservation here to prevent another |
| * process from stealing the pages as they are added to the pool but |
| * before they are reserved. |
| */ |
| needed += allocated; |
| h->resv_huge_pages += delta; |
| ret = 0; |
| |
| /* Free the needed pages to the hugetlb pool */ |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| if ((--needed) < 0) |
| break; |
| /* |
| * This page is now managed by the hugetlb allocator and has |
| * no users -- drop the buddy allocator's reference. |
| */ |
| put_page_testzero(page); |
| VM_BUG_ON_PAGE(page_count(page), page); |
| enqueue_huge_page(h, page); |
| } |
| free: |
| spin_unlock(&hugetlb_lock); |
| |
| /* Free unnecessary surplus pages to the buddy allocator */ |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) |
| put_page(page); |
| spin_lock(&hugetlb_lock); |
| |
| return ret; |
| } |
| |
| /* |
| * This routine has two main purposes: |
| * 1) Decrement the reservation count (resv_huge_pages) by the value passed |
| * in unused_resv_pages. This corresponds to the prior adjustments made |
| * to the associated reservation map. |
| * 2) Free any unused surplus pages that may have been allocated to satisfy |
| * the reservation. As many as unused_resv_pages may be freed. |
| * |
| * Called with hugetlb_lock held. However, the lock could be dropped (and |
| * reacquired) during calls to cond_resched_lock. Whenever dropping the lock, |
| * we must make sure nobody else can claim pages we are in the process of |
| * freeing. Do this by ensuring resv_huge_page always is greater than the |
| * number of huge pages we plan to free when dropping the lock. |
| */ |
| static void return_unused_surplus_pages(struct hstate *h, |
| unsigned long unused_resv_pages) |
| { |
| unsigned long nr_pages; |
| |
| /* Cannot return gigantic pages currently */ |
| if (hstate_is_gigantic(h)) |
| goto out; |
| |
| /* |
| * Part (or even all) of the reservation could have been backed |
| * by pre-allocated pages. Only free surplus pages. |
| */ |
| nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
| |
| /* |
| * We want to release as many surplus pages as possible, spread |
| * evenly across all nodes with memory. Iterate across these nodes |
| * until we can no longer free unreserved surplus pages. This occurs |
| * when the nodes with surplus pages have no free pages. |
| * free_pool_huge_page() will balance the the freed pages across the |
| * on-line nodes with memory and will handle the hstate accounting. |
| * |
| * Note that we decrement resv_huge_pages as we free the pages. If |
| * we drop the lock, resv_huge_pages will still be sufficiently large |
| * to cover subsequent pages we may free. |
| */ |
| while (nr_pages--) { |
| h->resv_huge_pages--; |
| unused_resv_pages--; |
| if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) |
| goto out; |
| cond_resched_lock(&hugetlb_lock); |
| } |
| |
| out: |
| /* Fully uncommit the reservation */ |
| h->resv_huge_pages -= unused_resv_pages; |
| } |
| |
| |
| /* |
| * vma_needs_reservation, vma_commit_reservation and vma_end_reservation |
| * are used by the huge page allocation routines to manage reservations. |
| * |
| * vma_needs_reservation is called to determine if the huge page at addr |
| * within the vma has an associated reservation. If a reservation is |
| * needed, the value 1 is returned. The caller is then responsible for |
| * managing the global reservation and subpool usage counts. After |
| * the huge page has been allocated, vma_commit_reservation is called |
| * to add the page to the reservation map. If the page allocation fails, |
| * the reservation must be ended instead of committed. vma_end_reservation |
| * is called in such cases. |
| * |
| * In the normal case, vma_commit_reservation returns the same value |
| * as the preceding vma_needs_reservation call. The only time this |
| * is not the case is if a reserve map was changed between calls. It |
| * is the responsibility of the caller to notice the difference and |
| * take appropriate action. |
| * |
| * vma_add_reservation is used in error paths where a reservation must |
| * be restored when a newly allocated huge page must be freed. It is |
| * to be called after calling vma_needs_reservation to determine if a |
| * reservation exists. |
| */ |
| enum vma_resv_mode { |
| VMA_NEEDS_RESV, |
| VMA_COMMIT_RESV, |
| VMA_END_RESV, |
| VMA_ADD_RESV, |
| }; |
| static long __vma_reservation_common(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr, |
| enum vma_resv_mode mode) |
| { |
| struct resv_map *resv; |
| pgoff_t idx; |
| long ret; |
| |
| resv = vma_resv_map(vma); |
| if (!resv) |
| return 1; |
| |
| idx = vma_hugecache_offset(h, vma, addr); |
| switch (mode) { |
| case VMA_NEEDS_RESV: |
| ret = region_chg(resv, idx, idx + 1); |
| break; |
| case VMA_COMMIT_RESV: |
| ret = region_add(resv, idx, idx + 1); |
| break; |
| case VMA_END_RESV: |
| region_abort(resv, idx, idx + 1); |
| ret = 0; |
| break; |
| case VMA_ADD_RESV: |
| if (vma->vm_flags & VM_MAYSHARE) |
| ret = region_add(resv, idx, idx + 1); |
| else { |
| region_abort(resv, idx, idx + 1); |
| ret = region_del(resv, idx, idx + 1); |
| } |
| break; |
| default: |
| BUG(); |
| } |
| |
| if (vma->vm_flags & VM_MAYSHARE) |
| return ret; |
| else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) { |
| /* |
| * In most cases, reserves always exist for private mappings. |
| * However, a file associated with mapping could have been |
| * hole punched or truncated after reserves were consumed. |
| * As subsequent fault on such a range will not use reserves. |
| * Subtle - The reserve map for private mappings has the |
| * opposite meaning than that of shared mappings. If NO |
| * entry is in the reserve map, it means a reservation exists. |
| * If an entry exists in the reserve map, it means the |
| * reservation has already been consumed. As a result, the |
| * return value of this routine is the opposite of the |
| * value returned from reserve map manipulation routines above. |
| */ |
| if (ret) |
| return 0; |
| else |
| return 1; |
| } |
| else |
| return ret < 0 ? ret : 0; |
| } |
| |
| static long vma_needs_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV); |
| } |
| |
| static long vma_commit_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV); |
| } |
| |
| static void vma_end_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV); |
| } |
| |
| static long vma_add_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV); |
| } |
| |
| /* |
| * This routine is called to restore a reservation on error paths. In the |
| * specific error paths, a huge page was allocated (via alloc_huge_page) |
| * and is about to be freed. If a reservation for the page existed, |
| * alloc_huge_page would have consumed the reservation and set PagePrivate |
| * in the newly allocated page. When the page is freed via free_huge_page, |
| * the global reservation count will be incremented if PagePrivate is set. |
| * However, free_huge_page can not adjust the reserve map. Adjust the |
| * reserve map here to be consistent with global reserve count adjustments |
| * to be made by free_huge_page. |
| */ |
| static void restore_reserve_on_error(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address, |
| struct page *page) |
| { |
| if (unlikely(PagePrivate(page))) { |
| long rc = vma_needs_reservation(h, vma, address); |
| |
| if (unlikely(rc < 0)) { |
| /* |
| * Rare out of memory condition in reserve map |
| * manipulation. Clear PagePrivate so that |
| * global reserve count will not be incremented |
| * by free_huge_page. This will make it appear |
| * as though the reservation for this page was |
| * consumed. This may prevent the task from |
| * faulting in the page at a later time. This |
| * is better than inconsistent global huge page |
| * accounting of reserve counts. |
| */ |
| ClearPagePrivate(page); |
| } else if (rc) { |
| rc = vma_add_reservation(h, vma, address); |
| if (unlikely(rc < 0)) |
| /* |
| * See above comment about rare out of |
| * memory condition. |
| */ |
| ClearPagePrivate(page); |
| } else |
| vma_end_reservation(h, vma, address); |
| } |
| } |
| |
| struct page *alloc_huge_page(struct vm_area_struct *vma, |
| unsigned long addr, int avoid_reserve) |
| { |
| struct hugepage_subpool *spool = subpool_vma(vma); |
| struct hstate *h = hstate_vma(vma); |
| struct page *page; |
| long map_chg, map_commit; |
| long gbl_chg; |
| int ret, idx; |
| struct hugetlb_cgroup *h_cg; |
| |
| idx = hstate_index(h); |
| /* |
| * Examine the region/reserve map to determine if the process |
| * has a reservation for the page to be allocated. A return |
| * code of zero indicates a reservation exists (no change). |
| */ |
| map_chg = gbl_chg = vma_needs_reservation(h, vma, addr); |
| if (map_chg < 0) |
| return ERR_PTR(-ENOMEM); |
| |
| /* |
| * Processes that did not create the mapping will have no |
| * reserves as indicated by the region/reserve map. Check |
| * that the allocation will not exceed the subpool limit. |
| * Allocations for MAP_NORESERVE mappings also need to be |
| * checked against any subpool limit. |
| */ |
| if (map_chg || avoid_reserve) { |
| gbl_chg = hugepage_subpool_get_pages(spool, 1); |
| if (gbl_chg < 0) { |
| vma_end_reservation(h, vma, addr); |
| return ERR_PTR(-ENOSPC); |
| } |
| |
| /* |
| * Even though there was no reservation in the region/reserve |
| * map, there could be reservations associated with the |
| * subpool that can be used. This would be indicated if the |
| * return value of hugepage_subpool_get_pages() is zero. |
| * However, if avoid_reserve is specified we still avoid even |
| * the subpool reservations. |
| */ |
| if (avoid_reserve) |
| gbl_chg = 1; |
| } |
| |
| ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); |
| if (ret) |
| goto out_subpool_put; |
| |
| spin_lock(&hugetlb_lock); |
| /* |
| * glb_chg is passed to indicate whether or not a page must be taken |
| * from the global free pool (global change). gbl_chg == 0 indicates |
| * a reservation exists for the allocation. |
| */ |
| page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg); |
| if (!page) { |
| spin_unlock(&hugetlb_lock); |
| page = __alloc_buddy_huge_page_with_mpol(h, vma, addr); |
| if (!page) |
| goto out_uncharge_cgroup; |
| spin_lock(&hugetlb_lock); |
| if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { |
| SetPagePrivate(page); |
| h->resv_huge_pages--; |
| } |
| list_move(&page->lru, &h->hugepage_activelist); |
| /* Fall through */ |
| } |
| hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); |
| spin_unlock(&hugetlb_lock); |
| |
| set_page_private(page, (unsigned long)spool); |
| |
| map_commit = vma_commit_reservation(h, vma, addr); |
| if (unlikely(map_chg > map_commit)) { |
| /* |
| * The page was added to the reservation map between |
| * vma_needs_reservation and vma_commit_reservation. |
| * This indicates a race with hugetlb_reserve_pages. |
| * Adjust for the subpool count incremented above AND |
| * in hugetlb_reserve_pages for the same page. Also, |
| * the reservation count added in hugetlb_reserve_pages |
| * no longer applies. |
| */ |
| long rsv_adjust; |
| |
| rsv_adjust = hugepage_subpool_put_pages(spool, 1); |
| hugetlb_acct_memory(h, -rsv_adjust); |
| } |
| return page; |
| |
| out_uncharge_cgroup: |
| hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); |
| out_subpool_put: |
| if (map_chg || avoid_reserve) |
| hugepage_subpool_put_pages(spool, 1); |
| vma_end_reservation(h, vma, addr); |
| return ERR_PTR(-ENOSPC); |
| } |
| |
| /* |
| * alloc_huge_page()'s wrapper which simply returns the page if allocation |
| * succeeds, otherwise NULL. This function is called from new_vma_page(), |
| * where no ERR_VALUE is expected to be returned. |
| */ |
| struct page *alloc_huge_page_noerr(struct vm_area_struct *vma, |
| unsigned long addr, int avoid_reserve) |
| { |
| struct page *page = alloc_huge_page(vma, addr, avoid_reserve); |
| if (IS_ERR(page)) |
| page = NULL; |
| return page; |
| } |
| |
| int alloc_bootmem_huge_page(struct hstate *h) |
| __attribute__ ((weak, alias("__alloc_bootmem_huge_page"))); |
| int __alloc_bootmem_huge_page(struct hstate *h) |
| { |
| struct huge_bootmem_page *m; |
| int nr_nodes, node; |
| |
| for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { |
| void *addr; |
| |
| addr = memblock_virt_alloc_try_nid_nopanic( |
| huge_page_size(h), huge_page_size(h), |
| 0, BOOTMEM_ALLOC_ACCESSIBLE, node); |
| if (addr) { |
| /* |
| * Use the beginning of the huge page to store the |
| * huge_bootmem_page struct (until gather_bootmem |
| * puts them into the mem_map). |
| */ |
| m = addr; |
| goto found; |
| } |
| } |
| return 0; |
| |
| found: |
| BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h))); |
| /* Put them into a private list first because mem_map is not up yet */ |
| list_add(&m->list, &huge_boot_pages); |
| m->hstate = h; |
| return 1; |
| } |
| |
| static void __init prep_compound_huge_page(struct page *page, |
| unsigned int order) |
| { |
| if (unlikely(order > (MAX_ORDER - 1))) |
| prep_compound_gigantic_page(page, order); |
| else |
| prep_compound_page(page, order); |
| } |
| |
| /* Put bootmem huge pages into the standard lists after mem_map is up */ |
| static void __init gather_bootmem_prealloc(void) |
| { |
| struct huge_bootmem_page *m; |
| |
| list_for_each_entry(m, &huge_boot_pages, list) { |
| struct hstate *h = m->hstate; |
| struct page *page; |
| |
| #ifdef CONFIG_HIGHMEM |
| page = pfn_to_page(m->phys >> PAGE_SHIFT); |
| memblock_free_late(__pa(m), |
| sizeof(struct huge_bootmem_page)); |
| #else |
| page = virt_to_page(m); |
| #endif |
| WARN_ON(page_count(page) != 1); |
| prep_compound_huge_page(page, h->order); |
| WARN_ON(PageReserved(page)); |
| prep_new_huge_page(h, page, page_to_nid(page)); |
| /* |
| * If we had gigantic hugepages allocated at boot time, we need |
| * to restore the 'stolen' pages to totalram_pages in order to |
| * fix confusing memory reports from free(1) and another |
| * side-effects, like CommitLimit going negative. |
| */ |
| if (hstate_is_gigantic(h)) |
| adjust_managed_page_count(page, 1 << h->order); |
| cond_resched(); |
| } |
| } |
| |
| static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
| { |
| unsigned long i; |
| |
| for (i = 0; i < h->max_huge_pages; ++i) { |
| if (hstate_is_gigantic(h)) { |
| if (!alloc_bootmem_huge_page(h)) |
| break; |
| } else if (!alloc_fresh_huge_page(h, |
| &node_states[N_MEMORY])) |
| break; |
| cond_resched(); |
| } |
| if (i < h->max_huge_pages) { |
| char buf[32]; |
| |
| string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
| pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n", |
| h->max_huge_pages, buf, i); |
| h->max_huge_pages = i; |
| } |
| } |
| |
| static void __init hugetlb_init_hstates(void) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| if (minimum_order > huge_page_order(h)) |
| minimum_order = huge_page_order(h); |
| |
| /* oversize hugepages were init'ed in early boot */ |
| if (!hstate_is_gigantic(h)) |
| hugetlb_hstate_alloc_pages(h); |
| } |
| VM_BUG_ON(minimum_order == UINT_MAX); |
| } |
| |
| static void __init report_hugepages(void) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| char buf[32]; |
| |
| string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
| pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", |
| buf, h->free_huge_pages); |
| } |
| } |
| |
| #ifdef CONFIG_HIGHMEM |
| static void try_to_free_low(struct hstate *h, unsigned long count, |
| nodemask_t *nodes_allowed) |
| { |
| int i; |
| |
| if (hstate_is_gigantic(h)) |
| return; |
| |
| for_each_node_mask(i, *nodes_allowed) { |
| struct page *page, *next; |
| struct list_head *freel = &h->hugepage_freelists[i]; |
| list_for_each_entry_safe(page, next, freel, lru) { |
| if (count >= h->nr_huge_pages) |
| return; |
| if (PageHighMem(page)) |
| continue; |
| list_del(&page->lru); |
| update_and_free_page(h, page); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[page_to_nid(page)]--; |
| } |
| } |
| } |
| #else |
| static inline void try_to_free_low(struct hstate *h, unsigned long count, |
| nodemask_t *nodes_allowed) |
| { |
| } |
| #endif |
| |
| /* |
| * Increment or decrement surplus_huge_pages. Keep node-specific counters |
| * balanced by operating on them in a round-robin fashion. |
| * Returns 1 if an adjustment was made. |
| */ |
| static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, |
| int delta) |
| { |
| int nr_nodes, node; |
| |
| VM_BUG_ON(delta != -1 && delta != 1); |
| |
| if (delta < 0) { |
| for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
| if (h->surplus_huge_pages_node[node]) |
| goto found; |
| } |
| } else { |
| for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
| if (h->surplus_huge_pages_node[node] < |
| h->nr_huge_pages_node[node]) |
| goto found; |
| } |
| } |
| return 0; |
| |
| found: |
| h->surplus_huge_pages += delta; |
| h->surplus_huge_pages_node[node] += delta; |
| return 1; |
| } |
| |
| #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
| static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, |
| nodemask_t *nodes_allowed) |
| { |
| unsigned long min_count, ret; |
| |
| if (hstate_is_gigantic(h) && !gigantic_page_supported()) |
| return h->max_huge_pages; |
| |
| /* |
| * Increase the pool size |
| * First take pages out of surplus state. Then make up the |
| * remaining difference by allocating fresh huge pages. |
| * |
| * We might race with __alloc_buddy_huge_page() here and be unable |
| * to convert a surplus huge page to a normal huge page. That is |
| * not critical, though, it just means the overall size of the |
| * pool might be one hugepage larger than it needs to be, but |
| * within all the constraints specified by the sysctls. |
| */ |
| spin_lock(&hugetlb_lock); |
| while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
| if (!adjust_pool_surplus(h, nodes_allowed, -1)) |
| break; |
| } |
| |
| while (count > persistent_huge_pages(h)) { |
| /* |
| * If this allocation races such that we no longer need the |
| * page, free_huge_page will handle it by freeing the page |
| * and reducing the surplus. |
| */ |
| spin_unlock(&hugetlb_lock); |
| |
| /* yield cpu to avoid soft lockup */ |
| cond_resched(); |
| |
| if (hstate_is_gigantic(h)) |
| ret = alloc_fresh_gigantic_page(h, nodes_allowed); |
| else |
| ret = alloc_fresh_huge_page(h, nodes_allowed); |
| spin_lock(&hugetlb_lock); |
| if (!ret) |
| goto out; |
| |
| /* Bail for signals. Probably ctrl-c from user */ |
| if (signal_pending(current)) |
| goto out; |
| } |
| |
| /* |
| * Decrease the pool size |
| * First return free pages to the buddy allocator (being careful |
| * to keep enough around to satisfy reservations). Then place |
| * pages into surplus state as needed so the pool will shrink |
| * to the desired size as pages become free. |
| * |
| * By placing pages into the surplus state independent of the |
| * overcommit value, we are allowing the surplus pool size to |
| * exceed overcommit. There are few sane options here. Since |
| * __alloc_buddy_huge_page() is checking the global counter, |
| * though, we'll note that we're not allowed to exceed surplus |
| * and won't grow the pool anywhere else. Not until one of the |
| * sysctls are changed, or the surplus pages go out of use. |
| */ |
| min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
| min_count = max(count, min_count); |
| try_to_free_low(h, min_count, nodes_allowed); |
| while (min_count < persistent_huge_pages(h)) { |
| if (!free_pool_huge_page(h, nodes_allowed, 0)) |
| break; |
| cond_resched_lock(&hugetlb_lock); |
| } |
| while (count < persistent_huge_pages(h)) { |
| if (!adjust_pool_surplus(h, nodes_allowed, 1)) |
| break; |
| } |
| out: |
| ret = persistent_huge_pages(h); |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| #define HSTATE_ATTR_RO(_name) \ |
| static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
| |
| #define HSTATE_ATTR(_name) \ |
| static struct kobj_attribute _name##_attr = \ |
| __ATTR(_name, 0644, _name##_show, _name##_store) |
| |
| static struct kobject *hugepages_kobj; |
| static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
| |
| static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); |
| |
| static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) |
| { |
| int i; |
| |
| for (i = 0; i < HUGE_MAX_HSTATE; i++) |
| if (hstate_kobjs[i] == kobj) { |
| if (nidp) |
| *nidp = NUMA_NO_NODE; |
| return &hstates[i]; |
| } |
| |
| return kobj_to_node_hstate(kobj, nidp); |
| } |
| |
| static ssize_t nr_hugepages_show_common(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h; |
| unsigned long nr_huge_pages; |
| int nid; |
| |
| h = kobj_to_hstate(kobj, &nid); |
| if (nid == NUMA_NO_NODE) |
| nr_huge_pages = h->nr_huge_pages; |
| else |
| nr_huge_pages = h->nr_huge_pages_node[nid]; |
| |
| return sprintf(buf, "%lu\n", nr_huge_pages); |
| } |
| |
| static ssize_t __nr_hugepages_store_common(bool obey_mempolicy, |
| struct hstate *h, int nid, |
| unsigned long count, size_t len) |
| { |
| int err; |
| NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); |
| |
| if (hstate_is_gigantic(h) && !gigantic_page_supported()) { |
| err = -EINVAL; |
| goto out; |
| } |
| |
| if (nid == NUMA_NO_NODE) { |
| /* |
| * global hstate attribute |
| */ |
| if (!(obey_mempolicy && |
| init_nodemask_of_mempolicy(nodes_allowed))) { |
| NODEMASK_FREE(nodes_allowed); |
| nodes_allowed = &node_states[N_MEMORY]; |
| } |
| } else if (nodes_allowed) { |
| /* |
| * per node hstate attribute: adjust count to global, |
| * but restrict alloc/free to the specified node. |
| */ |
| count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; |
| init_nodemask_of_node(nodes_allowed, nid); |
| } else |
| nodes_allowed = &node_states[N_MEMORY]; |
| |
| h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); |
| |
| if (nodes_allowed != &node_states[N_MEMORY]) |
| NODEMASK_FREE(nodes_allowed); |
| |
| return len; |
| out: |
| NODEMASK_FREE(nodes_allowed); |
| return err; |
| } |
| |
| static ssize_t nr_hugepages_store_common(bool obey_mempolicy, |
| struct kobject *kobj, const char *buf, |
| size_t len) |
| { |
| struct hstate *h; |
| unsigned long count; |
| int nid; |
| int err; |
| |
| err = kstrtoul(buf, 10, &count); |
| if (err) |
| return err; |
| |
| h = kobj_to_hstate(kobj, &nid); |
| return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len); |
| } |
| |
| static ssize_t nr_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| return nr_hugepages_show_common(kobj, attr, buf); |
| } |
| |
| static ssize_t nr_hugepages_store(struct kobject *kobj, |
| struct kobj_attribute *attr, const char *buf, size_t len) |
| { |
| return nr_hugepages_store_common(false, kobj, buf, len); |
| } |
| HSTATE_ATTR(nr_hugepages); |
| |
| #ifdef CONFIG_NUMA |
| |
| /* |
| * hstate attribute for optionally mempolicy-based constraint on persistent |
| * huge page alloc/free. |
| */ |
| static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| return nr_hugepages_show_common(kobj, attr, buf); |
| } |
| |
| static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, |
| struct kobj_attribute *attr, const char *buf, size_t len) |
| { |
| return nr_hugepages_store_common(true, kobj, buf, len); |
| } |
| HSTATE_ATTR(nr_hugepages_mempolicy); |
| #endif |
| |
| |
| static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h = kobj_to_hstate(kobj, NULL); |
| return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); |
| } |
| |
| static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, |
| struct kobj_attribute *attr, const char *buf, size_t count) |
| { |
| int err; |
| unsigned long input; |
| struct hstate *h = kobj_to_hstate(kobj, NULL); |
| |
| if (hstate_is_gigantic(h)) |
| return -EINVAL; |
| |
| err = kstrtoul(buf, 10, &input); |
| if (err) |
| return err; |
| |
| spin_lock(&hugetlb_lock); |
| h->nr_overcommit_huge_pages = input; |
| spin_unlock(&hugetlb_lock); |
| |
| return count; |
| } |
| HSTATE_ATTR(nr_overcommit_hugepages); |
| |
| static ssize_t free_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h; |
| unsigned long free_huge_pages; |
| int nid; |
| |
| h = kobj_to_hstate(kobj, &nid); |
| if (nid == NUMA_NO_NODE) |
| free_huge_pages = h->free_huge_pages; |
| else |
| free_huge_pages = h->free_huge_pages_node[nid]; |
| |
| return sprintf(buf, "%lu\n", free_huge_pages); |
| } |
| HSTATE_ATTR_RO(free_hugepages); |
| |
| static ssize_t resv_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h = kobj_to_hstate(kobj, NULL); |
| return sprintf(buf, "%lu\n", h->resv_huge_pages); |
| } |
| HSTATE_ATTR_RO(resv_hugepages); |
| |
| static ssize_t surplus_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h; |
| unsigned long surplus_huge_pages; |
| int nid; |
| |
| h = kobj_to_hstate(kobj, &nid); |
| if (nid == NUMA_NO_NODE) |
| surplus_huge_pages = h->surplus_huge_pages; |
| else |
| surplus_huge_pages = h->surplus_huge_pages_node[nid]; |
| |
| return sprintf(buf, "%lu\n", surplus_huge_pages); |
| } |
| HSTATE_ATTR_RO(surplus_hugepages); |
| |
| static struct attribute *hstate_attrs[] = { |
| &nr_hugepages_attr.attr, |
| &nr_overcommit_hugepages_attr.attr, |
| &free_hugepages_attr.attr, |
| &resv_hugepages_attr.attr, |
| &surplus_hugepages_attr.attr, |
| #ifdef CONFIG_NUMA |
| &nr_hugepages_mempolicy_attr.attr, |
| #endif |
| NULL, |
| }; |
| |
| static const struct attribute_group hstate_attr_group = { |
| .attrs = hstate_attrs, |
| }; |
| |
| static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, |
| struct kobject **hstate_kobjs, |
| const struct attribute_group *hstate_attr_group) |
| { |
| int retval; |
| int hi = hstate_index(h); |
| |
| hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); |
| if (!hstate_kobjs[hi]) |
| return -ENOMEM; |
| |
| retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); |
| if (retval) { |
| kobject_put(hstate_kobjs[hi]); |
| hstate_kobjs[hi] = NULL; |
| } |
| |
| return retval; |
| } |
| |
| static void __init hugetlb_sysfs_init(void) |
| { |
| struct hstate *h; |
| int err; |
| |
| hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); |
| if (!hugepages_kobj) |
| return; |
| |
| for_each_hstate(h) { |
| err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, |
| hstate_kobjs, &hstate_attr_group); |
| if (err) |
| pr_err("Hugetlb: Unable to add hstate %s", h->name); |
| } |
| } |
| |
| #ifdef CONFIG_NUMA |
| |
| /* |
| * node_hstate/s - associate per node hstate attributes, via their kobjects, |
| * with node devices in node_devices[] using a parallel array. The array |
| * index of a node device or _hstate == node id. |
| * This is here to avoid any static dependency of the node device driver, in |
| * the base kernel, on the hugetlb module. |
| */ |
| struct node_hstate { |
| struct kobject *hugepages_kobj; |
| struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
| }; |
| static struct node_hstate node_hstates[MAX_NUMNODES]; |
| |
| /* |
| * A subset of global hstate attributes for node devices |
| */ |
| static struct attribute *per_node_hstate_attrs[] = { |
| &nr_hugepages_attr.attr, |
| &free_hugepages_attr.attr, |
| &surplus_hugepages_attr.attr, |
| NULL, |
| }; |
| |
| static const struct attribute_group per_node_hstate_attr_group = { |
| .attrs = per_node_hstate_attrs, |
| }; |
| |
| /* |
| * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. |
| * Returns node id via non-NULL nidp. |
| */ |
| static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
| { |
| int nid; |
| |
| for (nid = 0; nid < nr_node_ids; nid++) { |
| struct node_hstate *nhs = &node_hstates[nid]; |
| int i; |
| for (i = 0; i < HUGE_MAX_HSTATE; i++) |
| if (nhs->hstate_kobjs[i] == kobj) { |
| if (nidp) |
| *nidp = nid; |
| return &hstates[i]; |
| } |
| } |
| |
| BUG(); |
| return NULL; |
| } |
| |
| /* |
| * Unregister hstate attributes from a single node device. |
| * No-op if no hstate attributes attached. |
| */ |
| static void hugetlb_unregister_node(struct node *node) |
| { |
| struct hstate *h; |
| struct node_hstate *nhs = &node_hstates[node->dev.id]; |
| |
| if (!nhs->hugepages_kobj) |
| return; /* no hstate attributes */ |
| |
| for_each_hstate(h) { |
| int idx = hstate_index(h); |
| if (nhs->hstate_kobjs[idx]) { |
| kobject_put(nhs->hstate_kobjs[idx]); |
| nhs->hstate_kobjs[idx] = NULL; |
| } |
| } |
| |
| kobject_put(nhs->hugepages_kobj); |
| nhs->hugepages_kobj = NULL; |
| } |
| |
| |
| /* |
| * Register hstate attributes for a single node device. |
| * No-op if attributes already registered. |
| */ |
| static void hugetlb_register_node(struct node *node) |
| { |
| struct hstate *h; |
| struct node_hstate *nhs = &node_hstates[node->dev.id]; |
| int err; |
| |
| if (nhs->hugepages_kobj) |
| return; /* already allocated */ |
| |
| nhs->hugepages_kobj = kobject_create_and_add("hugepages", |
| &node->dev.kobj); |
| if (!nhs->hugepages_kobj) |
| return; |
| |
| for_each_hstate(h) { |
| err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, |
| nhs->hstate_kobjs, |
| &per_node_hstate_attr_group); |
| if (err) { |
| pr_err("Hugetlb: Unable to add hstate %s for node %d\n", |
| h->name, node->dev.id); |
| hugetlb_unregister_node(node); |
| break; |
| } |
| } |
| } |
| |
| /* |
| * hugetlb init time: register hstate attributes for all registered node |
| * devices of nodes that have memory. All on-line nodes should have |
| * registered their associated device by this time. |
| */ |
| static void __init hugetlb_register_all_nodes(void) |
| { |
| int nid; |
| |
| for_each_node_state(nid, N_MEMORY) { |
| struct node *node = node_devices[nid]; |
| if (node->dev.id == nid) |
| hugetlb_register_node(node); |
| } |
| |
| /* |
| * Let the node device driver know we're here so it can |
| * [un]register hstate attributes on node hotplug. |
| */ |
| register_hugetlbfs_with_node(hugetlb_register_node, |
| hugetlb_unregister_node); |
| } |
| #else /* !CONFIG_NUMA */ |
| |
| static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
| { |
| BUG(); |
| if (nidp) |
| *nidp = -1; |
| return NULL; |
| } |
| |
| static void hugetlb_register_all_nodes(void) { } |
| |
| #endif |
| |
| static int __init hugetlb_init(void) |
| { |
| int i; |
| |
| if (!hugepages_supported()) |
| return 0; |
| |
| if (!size_to_hstate(default_hstate_size)) { |
| if (default_hstate_size != 0) { |
| pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n", |
| default_hstate_size, HPAGE_SIZE); |
| } |
| |
| default_hstate_size = HPAGE_SIZE; |
| if (!size_to_hstate(default_hstate_size)) |
| hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
| } |
| default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); |
| if (default_hstate_max_huge_pages) { |
| if (!default_hstate.max_huge_pages) |
| default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
| } |
| |
| hugetlb_init_hstates(); |
| gather_bootmem_prealloc(); |
| report_hugepages(); |
| |
| hugetlb_sysfs_init(); |
| hugetlb_register_all_nodes(); |
| hugetlb_cgroup_file_init(); |
| |
| #ifdef CONFIG_SMP |
| num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); |
| #else |
| num_fault_mutexes = 1; |
| #endif |
| hugetlb_fault_mutex_table = |
| kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL); |
| BUG_ON(!hugetlb_fault_mutex_table); |
| |
| for (i = 0; i < num_fault_mutexes; i++) |
| mutex_init(&hugetlb_fault_mutex_table[i]); |
| return 0; |
| } |
| subsys_initcall(hugetlb_init); |
| |
| /* Should be called on processing a hugepagesz=... option */ |
| void __init hugetlb_bad_size(void) |
| { |
| parsed_valid_hugepagesz = false; |
| } |
| |
| void __init hugetlb_add_hstate(unsigned int order) |
| { |
| struct hstate *h; |
| unsigned long i; |
| |
| if (size_to_hstate(PAGE_SIZE << order)) { |
| pr_warn("hugepagesz= specified twice, ignoring\n"); |
| return; |
| } |
| BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); |
| BUG_ON(order == 0); |
| h = &hstates[hugetlb_max_hstate++]; |
| h->order = order; |
| h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
| h->nr_huge_pages = 0; |
| h->free_huge_pages = 0; |
| for (i = 0; i < MAX_NUMNODES; ++i) |
| INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
| INIT_LIST_HEAD(&h->hugepage_activelist); |
| h->next_nid_to_alloc = first_memory_node; |
| h->next_nid_to_free = first_memory_node; |
| snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", |
| huge_page_size(h)/1024); |
| |
| parsed_hstate = h; |
| } |
| |
| static int __init hugetlb_nrpages_setup(char *s) |
| { |
| unsigned long *mhp; |
| static unsigned long *last_mhp; |
| |
| if (!parsed_valid_hugepagesz) { |
| pr_warn("hugepages = %s preceded by " |
| "an unsupported hugepagesz, ignoring\n", s); |
| parsed_valid_hugepagesz = true; |
| return 1; |
| } |
| /* |
| * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, |
| * so this hugepages= parameter goes to the "default hstate". |
| */ |
| else if (!hugetlb_max_hstate) |
| mhp = &default_hstate_max_huge_pages; |
| else |
| mhp = &parsed_hstate->max_huge_pages; |
| |
| if (mhp == last_mhp) { |
| pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n"); |
| return 1; |
| } |
| |
| if (sscanf(s, "%lu", mhp) <= 0) |
| *mhp = 0; |
| |
| /* |
| * Global state is always initialized later in hugetlb_init. |
| * But we need to allocate >= MAX_ORDER hstates here early to still |
| * use the bootmem allocator. |
| */ |
| if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) |
| hugetlb_hstate_alloc_pages(parsed_hstate); |
| |
| last_mhp = mhp; |
| |
| return 1; |
| } |
| __setup("hugepages=", hugetlb_nrpages_setup); |
| |
| static int __init hugetlb_default_setup(char *s) |
| { |
| default_hstate_size = memparse(s, &s); |
| return 1; |
| } |
| __setup("default_hugepagesz=", hugetlb_default_setup); |
| |
| static unsigned int cpuset_mems_nr(unsigned int *array) |
| { |
| int node; |
| unsigned int nr = 0; |
| |
| for_each_node_mask(node, cpuset_current_mems_allowed) |
| nr += array[node]; |
| |
| return nr; |
| } |
| |
| #ifdef CONFIG_SYSCTL |
| static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write, |
| void *buffer, size_t *length, |
| loff_t *ppos, unsigned long *out) |
| { |
| struct ctl_table dup_table; |
| |
| /* |
| * In order to avoid races with __do_proc_doulongvec_minmax(), we |
| * can duplicate the @table and alter the duplicate of it. |
| */ |
| dup_table = *table; |
| dup_table.data = out; |
| |
| return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos); |
| } |
| |
| static int hugetlb_sysctl_handler_common(bool obey_mempolicy, |
| struct ctl_table *table, int write, |
| void __user *buffer, size_t *length, loff_t *ppos) |
| { |
| struct hstate *h = &default_hstate; |
| unsigned long tmp = h->max_huge_pages; |
| int ret; |
| |
| if (!hugepages_supported()) |
| return -EOPNOTSUPP; |
| |
| ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos, |
| &tmp); |
| if (ret) |
| goto out; |
| |
| if (write) |
| ret = __nr_hugepages_store_common(obey_mempolicy, h, |
| NUMA_NO_NODE, tmp, *length); |
| out: |
| return ret; |
| } |
| |
| int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *length, loff_t *ppos) |
| { |
| |
| return hugetlb_sysctl_handler_common(false, table, write, |
| buffer, length, ppos); |
| } |
| |
| #ifdef CONFIG_NUMA |
| int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, |
| void __user *buffer, size_t *length, loff_t *ppos) |
| { |
| return hugetlb_sysctl_handler_common(true, table, write, |
| buffer, length, ppos); |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
| void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| struct hstate *h = &default_hstate; |
| unsigned long tmp; |
| int ret; |
| |
| if (!hugepages_supported()) |
| return -EOPNOTSUPP; |
| |
| tmp = h->nr_overcommit_huge_pages; |
| |
| if (write && hstate_is_gigantic(h)) |
| return -EINVAL; |
| |
| ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos, |
| &tmp); |
| if (ret) |
| goto out; |
| |
| if (write) { |
| spin_lock(&hugetlb_lock); |
| h->nr_overcommit_huge_pages = tmp; |
| spin_unlock(&hugetlb_lock); |
| } |
| out: |
| return ret; |
| } |
| |
| #endif /* CONFIG_SYSCTL */ |
| |
| void hugetlb_report_meminfo(struct seq_file *m) |
| { |
| struct hstate *h = &default_hstate; |
| if (!hugepages_supported()) |
| return; |
| seq_printf(m, |
| "HugePages_Total: %5lu\n" |
| "HugePages_Free: %5lu\n" |
| "HugePages_Rsvd: %5lu\n" |
| "HugePages_Surp: %5lu\n" |
| "Hugepagesize: %8lu kB\n", |
| h->nr_huge_pages, |
| h->free_huge_pages, |
| h->resv_huge_pages, |
| h->surplus_huge_pages, |
| 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
| } |
| |
| int hugetlb_report_node_meminfo(int nid, char *buf) |
| { |
| struct hstate *h = &default_hstate; |
| if (!hugepages_supported()) |
| return 0; |
| return sprintf(buf, |
| "Node %d HugePages_Total: %5u\n" |
| "Node %d HugePages_Free: %5u\n" |
| "Node %d HugePages_Surp: %5u\n", |
| nid, h->nr_huge_pages_node[nid], |
| nid, h->free_huge_pages_node[nid], |
| nid, h->surplus_huge_pages_node[nid]); |
| } |
| |
| void hugetlb_show_meminfo(void) |
| { |
| struct hstate *h; |
| int nid; |
| |
| if (!hugepages_supported()) |
| return; |
| |
| for_each_node_state(nid, N_MEMORY) |
| for_each_hstate(h) |
| pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", |
| nid, |
| h->nr_huge_pages_node[nid], |
| h->free_huge_pages_node[nid], |
| h->surplus_huge_pages_node[nid], |
| 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
| } |
| |
| void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm) |
| { |
| seq_printf(m, "HugetlbPages:\t%8lu kB\n", |
| atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10)); |
| } |
| |
| /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
| unsigned long hugetlb_total_pages(void) |
| { |
| struct hstate *h; |
| unsigned long nr_total_pages = 0; |
| |
| for_each_hstate(h) |
| nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); |
| return nr_total_pages; |
| } |
| |
| static int hugetlb_acct_memory(struct hstate *h, long delta) |
| { |
| int ret = -ENOMEM; |
| |
| spin_lock(&hugetlb_lock); |
| /* |
| * When cpuset is configured, it breaks the strict hugetlb page |
| * reservation as the accounting is done on a global variable. Such |
| * reservation is completely rubbish in the presence of cpuset because |
| * the reservation is not checked against page availability for the |
| * current cpuset. Application can still potentially OOM'ed by kernel |
| * with lack of free htlb page in cpuset that the task is in. |
| * Attempt to enforce strict accounting with cpuset is almost |
| * impossible (or too ugly) because cpuset is too fluid that |
| * task or memory node can be dynamically moved between cpusets. |
| * |
| * The change of semantics for shared hugetlb mapping with cpuset is |
| * undesirable. However, in order to preserve some of the semantics, |
| * we fall back to check against current free page availability as |
| * a best attempt and hopefully to minimize the impact of changing |
| * semantics that cpuset has. |
| */ |
| if (delta > 0) { |
| if (gather_surplus_pages(h, delta) < 0) |
| goto out; |
| |
| if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
| return_unused_surplus_pages(h, delta); |
| goto out; |
| } |
| } |
| |
| ret = 0; |
| if (delta < 0) |
| return_unused_surplus_pages(h, (unsigned long) -delta); |
| |
| out: |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
| { |
| struct resv_map *resv = vma_resv_map(vma); |
| |
| /* |
| * This new VMA should share its siblings reservation map if present. |
| * The VMA will only ever have a valid reservation map pointer where |
| * it is being copied for another still existing VMA. As that VMA |
| * has a reference to the reservation map it cannot disappear until |
| * after this open call completes. It is therefore safe to take a |
| * new reference here without additional locking. |
| */ |
| if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| kref_get(&resv->refs); |
| } |
| |
| static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
| { |
| struct hstate *h = hstate_vma(vma); |
| struct resv_map *resv = vma_resv_map(vma); |
| struct hugepage_subpool *spool = subpool_vma(vma); |
| unsigned long reserve, start, end; |
| long gbl_reserve; |
| |
| if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| return; |
| |
| start = vma_hugecache_offset(h, vma, vma->vm_start); |
| end = vma_hugecache_offset(h, vma, vma->vm_end); |
| |
| reserve = (end - start) - region_count(resv, start, end); |
| |
| kref_put(&resv->refs, resv_map_release); |
| |
| if (reserve) { |
| /* |
| * Decrement reserve counts. The global reserve count may be |
| * adjusted if the subpool has a minimum size. |
| */ |
| gbl_reserve = hugepage_subpool_put_pages(spool, reserve); |
| hugetlb_acct_memory(h, -gbl_reserve); |
| } |
| } |
| |
| static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr) |
| { |
| if (addr & ~(huge_page_mask(hstate_vma(vma)))) |
| return -EINVAL; |
| return 0; |
| } |
| |
| /* |
| * We cannot handle pagefaults against hugetlb pages at all. They cause |
| * handle_mm_fault() to try to instantiate regular-sized pages in the |
| * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
| * this far. |
| */ |
| static int hugetlb_vm_op_fault(struct vm_fault *vmf) |
| { |
| BUG(); |
| return 0; |
| } |
| |
| const struct vm_operations_struct hugetlb_vm_ops = { |
| .fault = hugetlb_vm_op_fault, |
| .open = hugetlb_vm_op_open, |
| .close = hugetlb_vm_op_close, |
| .split = hugetlb_vm_op_split, |
| }; |
| |
| static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
| int writable) |
| { |
| pte_t entry; |
| |
| if (writable) { |
| entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, |
| vma->vm_page_prot))); |
| } else { |
| entry = huge_pte_wrprotect(mk_huge_pte(page, |
| vma->vm_page_prot)); |
| } |
| entry = pte_mkyoung(entry); |
| entry = pte_mkhuge(entry); |
| entry = arch_make_huge_pte(entry, vma, page, writable); |
| |
| return entry; |
| } |
| |
| static void set_huge_ptep_writable(struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep) |
| { |
| pte_t entry; |
| |
| entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); |
| if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) |
| update_mmu_cache(vma, address, ptep); |
| } |
| |
| bool is_hugetlb_entry_migration(pte_t pte) |
| { |
| swp_entry_t swp; |
| |
| if (huge_pte_none(pte) || pte_present(pte)) |
| return false; |
| swp = pte_to_swp_entry(pte); |
| if (non_swap_entry(swp) && is_migration_entry(swp)) |
| return true; |
| else |
| return false; |
| } |
| |
| static int is_hugetlb_entry_hwpoisoned(pte_t pte) |
| { |
| swp_entry_t swp; |
| |
| if (huge_pte_none(pte) || pte_present(pte)) |
| return 0; |
| swp = pte_to_swp_entry(pte); |
| if (non_swap_entry(swp) && is_hwpoison_entry(swp)) |
| return 1; |
| else |
| return 0; |
| } |
| |
| int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
| struct vm_area_struct *vma) |
| { |
| pte_t *src_pte, *dst_pte, entry, dst_entry; |
| struct page *ptepage; |
| unsigned long addr; |
| int cow; |
| struct hstate *h = hstate_vma(vma); |
| unsigned long sz = huge_page_size(h); |
| unsigned long mmun_start; /* For mmu_notifiers */ |
| unsigned long mmun_end; /* For mmu_notifiers */ |
| int ret = 0; |
| |
| cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
| |
| mmun_start = vma->vm_start; |
| mmun_end = vma->vm_end; |
| if (cow) |
| mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); |
| |
| for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
| spinlock_t *src_ptl, *dst_ptl; |
| src_pte = huge_pte_offset(src, addr, sz); |
| if (!src_pte) |
| continue; |
| dst_pte = huge_pte_alloc(dst, vma, addr, sz); |
| if (!dst_pte) { |
| ret = -ENOMEM; |
| break; |
| } |
| |
| /* |
| * If the pagetables are shared don't copy or take references. |
| * dst_pte == src_pte is the common case of src/dest sharing. |
| * |
| * However, src could have 'unshared' and dst shares with |
| * another vma. If dst_pte !none, this implies sharing. |
| * Check here before taking page table lock, and once again |
| * after taking the lock below. |
| */ |
| dst_entry = huge_ptep_get(dst_pte); |
| if ((dst_pte == src_pte) || !huge_pte_none(dst_entry)) |
| continue; |
| |
| dst_ptl = huge_pte_lock(h, dst, dst_pte); |
| src_ptl = huge_pte_lockptr(h, src, src_pte); |
| spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
| entry = huge_ptep_get(src_pte); |
| dst_entry = huge_ptep_get(dst_pte); |
| if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) { |
| /* |
| * Skip if src entry none. Also, skip in the |
| * unlikely case dst entry !none as this implies |
| * sharing with another vma. |
| */ |
| ; |
| } else if (unlikely(is_hugetlb_entry_migration(entry) || |
| is_hugetlb_entry_hwpoisoned(entry))) { |
| swp_entry_t swp_entry = pte_to_swp_entry(entry); |
| |
| if (is_write_migration_entry(swp_entry) && cow) { |
| /* |
| * COW mappings require pages in both |
| * parent and child to be set to read. |
| */ |
| make_migration_entry_read(&swp_entry); |
| entry = swp_entry_to_pte(swp_entry); |
| set_huge_swap_pte_at(src, addr, src_pte, |
| entry, sz); |
| } |
| set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz); |
| } else { |
| if (cow) { |
| huge_ptep_set_wrprotect(src, addr, src_pte); |
| mmu_notifier_invalidate_range(src, mmun_start, |
| mmun_end); |
| } |
| entry = huge_ptep_get(src_pte); |
| ptepage = pte_page(entry); |
| get_page(ptepage); |
| page_dup_rmap(ptepage, true); |
| set_huge_pte_at(dst, addr, dst_pte, entry); |
| hugetlb_count_add(pages_per_huge_page(h), dst); |
| } |
| spin_unlock(src_ptl); |
| spin_unlock(dst_ptl); |
| } |
| |
| if (cow) |
| mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); |
| |
| return ret; |
| } |
| |
| void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
| unsigned long start, unsigned long end, |
| struct page *ref_page) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long address; |
| pte_t *ptep; |
| pte_t pte; |
| spinlock_t *ptl; |
| struct page *page; |
| struct hstate *h = hstate_vma(vma); |
| unsigned long sz = huge_page_size(h); |
| unsigned long mmun_start = start; /* For mmu_notifiers */ |
| unsigned long mmun_end = end; /* For mmu_notifiers */ |
| bool force_flush = false; |
| |
| WARN_ON(!is_vm_hugetlb_page(vma)); |
| BUG_ON(start & ~huge_page_mask(h)); |
| BUG_ON(end & ~huge_page_mask(h)); |
| |
| /* |
| * This is a hugetlb vma, all the pte entries should point |
| * to huge page. |
| */ |
| tlb_remove_check_page_size_change(tlb, sz); |
| tlb_start_vma(tlb, vma); |
| |
| /* |
| * If sharing possible, alert mmu notifiers of worst case. |
| */ |
| adjust_range_if_pmd_sharing_possible(vma, &mmun_start, &mmun_end); |
| mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
| address = start; |
| for (; address < end; address += sz) { |
| ptep = huge_pte_offset(mm, address, sz); |
| if (!ptep) |
| continue; |
| |
| ptl = huge_pte_lock(h, mm, ptep); |
| if (huge_pmd_unshare(mm, &address, ptep)) { |
| spin_unlock(ptl); |
| tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE); |
| force_flush = true; |
| continue; |
| } |
| |
| pte = huge_ptep_get(ptep); |
| if (huge_pte_none(pte)) { |
| spin_unlock(ptl); |
| continue; |
| } |
| |
| /* |
| * Migrating hugepage or HWPoisoned hugepage is already |
| * unmapped and its refcount is dropped, so just clear pte here. |
| */ |
| if (unlikely(!pte_present(pte))) { |
| huge_pte_clear(mm, address, ptep, sz); |
| spin_unlock(ptl); |
| continue; |
| } |
| |
| page = pte_page(pte); |
| /* |
| * If a reference page is supplied, it is because a specific |
| * page is being unmapped, not a range. Ensure the page we |
| * are about to unmap is the actual page of interest. |
| */ |
| if (ref_page) { |
| if (page != ref_page) { |
| spin_unlock(ptl); |
| continue; |
| } |
| /* |
| * Mark the VMA as having unmapped its page so that |
| * future faults in this VMA will fail rather than |
| * looking like data was lost |
| */ |
| set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
| } |
| |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| tlb_remove_huge_tlb_entry(h, tlb, ptep, address); |
| if (huge_pte_dirty(pte)) |
| set_page_dirty(page); |
| |
| hugetlb_count_sub(pages_per_huge_page(h), mm); |
| page_remove_rmap(page, true); |
| |
| spin_unlock(ptl); |
| tlb_remove_page_size(tlb, page, huge_page_size(h)); |
| /* |
| * Bail out after unmapping reference page if supplied |
| */ |
| if (ref_page) |
| break; |
| } |
| mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
| tlb_end_vma(tlb, vma); |
| |
| /* |
| * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We |
| * could defer the flush until now, since by holding i_mmap_rwsem we |
| * guaranteed that the last refernece would not be dropped. But we must |
| * do the flushing before we return, as otherwise i_mmap_rwsem will be |
| * dropped and the last reference to the shared PMDs page might be |
| * dropped as well. |
| * |
| * In theory we could defer the freeing of the PMD pages as well, but |
| * huge_pmd_unshare() relies on the exact page_count for the PMD page to |
| * detect sharing, so we cannot defer the release of the page either. |
| * Instead, do flush now. |
| */ |
| if (force_flush) |
| tlb_flush_mmu(tlb); |
| } |
| |
| void __unmap_hugepage_range_final(struct mmu_gather *tlb, |
| struct vm_area_struct *vma, unsigned long start, |
| unsigned long end, struct page *ref_page) |
| { |
| __unmap_hugepage_range(tlb, vma, start, end, ref_page); |
| |
| /* |
| * Clear this flag so that x86's huge_pmd_share page_table_shareable |
| * test will fail on a vma being torn down, and not grab a page table |
| * on its way out. We're lucky that the flag has such an appropriate |
| * name, and can in fact be safely cleared here. We could clear it |
| * before the __unmap_hugepage_range above, but all that's necessary |
| * is to clear it before releasing the i_mmap_rwsem. This works |
| * because in the context this is called, the VMA is about to be |
| * destroyed and the i_mmap_rwsem is held. |
| */ |
| vma->vm_flags &= ~VM_MAYSHARE; |
| } |
| |
| void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| unsigned long end, struct page *ref_page) |
| { |
| struct mm_struct *mm; |
| struct mmu_gather tlb; |
| unsigned long tlb_start = start; |
| unsigned long tlb_end = end; |
| |
| /* |
| * If shared PMDs were possibly used within this vma range, adjust |
| * start/end for worst case tlb flushing. |
| * Note that we can not be sure if PMDs are shared until we try to |
| * unmap pages. However, we want to make sure TLB flushing covers |
| * the largest possible range. |
| */ |
| adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end); |
| |
| mm = vma->vm_mm; |
| |
| tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end); |
| __unmap_hugepage_range(&tlb, vma, start, end, ref_page); |
| tlb_finish_mmu(&tlb, tlb_start, tlb_end); |
| } |
| |
| /* |
| * This is called when the original mapper is failing to COW a MAP_PRIVATE |
| * mappping it owns the reserve page for. The intention is to unmap the page |
| * from other VMAs and let the children be SIGKILLed if they are faulting the |
| * same region. |
| */ |
| static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
| struct page *page, unsigned long address) |
| { |
| struct hstate *h = hstate_vma(vma); |
| struct vm_area_struct *iter_vma; |
| struct address_space *mapping; |
| pgoff_t pgoff; |
| |
| /* |
| * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
| * from page cache lookup which is in HPAGE_SIZE units. |
| */ |
| address = address & huge_page_mask(h); |
| pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + |
| vma->vm_pgoff; |
| mapping = vma->vm_file->f_mapping; |
| |
| /* |
| * Take the mapping lock for the duration of the table walk. As |
| * this mapping should be shared between all the VMAs, |
| * __unmap_hugepage_range() is called as the lock is already held |
| */ |
| i_mmap_lock_write(mapping); |
| vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { |
| /* Do not unmap the current VMA */ |
| if (iter_vma == vma) |
| continue; |
| |
| /* |
| * Shared VMAs have their own reserves and do not affect |
| * MAP_PRIVATE accounting but it is possible that a shared |
| * VMA is using the same page so check and skip such VMAs. |
| */ |
| if (iter_vma->vm_flags & VM_MAYSHARE) |
| continue; |
| |
| /* |
| * Unmap the page from other VMAs without their own reserves. |
| * They get marked to be SIGKILLed if they fault in these |
| * areas. This is because a future no-page fault on this VMA |
| * could insert a zeroed page instead of the data existing |
| * from the time of fork. This would look like data corruption |
| */ |
| if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
| unmap_hugepage_range(iter_vma, address, |
| address + huge_page_size(h), page); |
| } |
| i_mmap_unlock_write(mapping); |
| } |
| |
| /* |
| * Hugetlb_cow() should be called with page lock of the original hugepage held. |
| * Called with hugetlb_instantiation_mutex held and pte_page locked so we |
| * cannot race with other handlers or page migration. |
| * Keep the pte_same checks anyway to make transition from the mutex easier. |
| */ |
| static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, |
| struct page *pagecache_page, spinlock_t *ptl) |
| { |
| pte_t pte; |
| struct hstate *h = hstate_vma(vma); |
| struct page *old_page, *new_page; |
| int ret = 0, outside_reserve = 0; |
| unsigned long mmun_start; /* For mmu_notifiers */ |
| unsigned long mmun_end; /* For mmu_notifiers */ |
| |
| pte = huge_ptep_get(ptep); |
| old_page = pte_page(pte); |
| |
| retry_avoidcopy: |
| /* If no-one else is actually using this page, avoid the copy |
| * and just make the page writable */ |
| if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { |
| page_move_anon_rmap(old_page, vma); |
| set_huge_ptep_writable(vma, address, ptep); |
| return 0; |
| } |
| |
| /* |
| * If the process that created a MAP_PRIVATE mapping is about to |
| * perform a COW due to a shared page count, attempt to satisfy |
| * the allocation without using the existing reserves. The pagecache |
| * page is used to determine if the reserve at this address was |
| * consumed or not. If reserves were used, a partial faulted mapping |
| * at the time of fork() could consume its reserves on COW instead |
| * of the full address range. |
| */ |
| if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
| old_page != pagecache_page) |
| outside_reserve = 1; |
| |
| get_page(old_page); |
| |
| /* |
| * Drop page table lock as buddy allocator may be called. It will |
| * be acquired again before returning to the caller, as expected. |
| */ |
| spin_unlock(ptl); |
| new_page = alloc_huge_page(vma, address, outside_reserve); |
| |
| if (IS_ERR(new_page)) { |
| /* |
| * If a process owning a MAP_PRIVATE mapping fails to COW, |
| * it is due to references held by a child and an insufficient |
| * huge page pool. To guarantee the original mappers |
| * reliability, unmap the page from child processes. The child |
| * may get SIGKILLed if it later faults. |
| */ |
| if (outside_reserve) { |
| put_page(old_page); |
| BUG_ON(huge_pte_none(pte)); |
| unmap_ref_private(mm, vma, old_page, address); |
| BUG_ON(huge_pte_none(pte)); |
| spin_lock(ptl); |
| ptep = huge_pte_offset(mm, address & huge_page_mask(h), |
| huge_page_size(h)); |
| if (likely(ptep && |
| pte_same(huge_ptep_get(ptep), pte))) |
| goto retry_avoidcopy; |
| /* |
| * race occurs while re-acquiring page table |
| * lock, and our job is done. |
| */ |
| return 0; |
| } |
| |
| ret = (PTR_ERR(new_page) == -ENOMEM) ? |
| VM_FAULT_OOM : VM_FAULT_SIGBUS; |
| goto out_release_old; |
| } |
| |
| /* |
| * When the original hugepage is shared one, it does not have |
| * anon_vma prepared. |
| */ |
| if (unlikely(anon_vma_prepare(vma))) { |
| ret = VM_FAULT_OOM; |
| goto out_release_all; |
| } |
| |
| copy_user_huge_page(new_page, old_page, address, vma, |
| pages_per_huge_page(h)); |
| __SetPageUptodate(new_page); |
| |
| mmun_start = address & huge_page_mask(h); |
| mmun_end = mmun_start + huge_page_size(h); |
| mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
| |
| /* |
| * Retake the page table lock to check for racing updates |
| * before the page tables are altered |
| */ |
| spin_lock(ptl); |
| ptep = huge_pte_offset(mm, address & huge_page_mask(h), |
| huge_page_size(h)); |
| if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { |
| ClearPagePrivate(new_page); |
| |
| /* Break COW */ |
| huge_ptep_clear_flush(vma, address, ptep); |
| mmu_notifier_invalidate_range(mm, mmun_start, mmun_end); |
| set_huge_pte_at(mm, address, ptep, |
| make_huge_pte(vma, new_page, 1)); |
| page_remove_rmap(old_page, true); |
| hugepage_add_new_anon_rmap(new_page, vma, address); |
| set_page_huge_active(new_page); |
| /* Make the old page be freed below */ |
| new_page = old_page; |
| } |
| spin_unlock(ptl); |
| mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
| out_release_all: |
| restore_reserve_on_error(h, vma, address, new_page); |
| put_page(new_page); |
| out_release_old: |
| put_page(old_page); |
| |
| spin_lock(ptl); /* Caller expects lock to be held */ |
| return ret; |
| } |
| |
| /* Return the pagecache page at a given address within a VMA */ |
| static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address) |
| { |
| struct address_space *mapping; |
| pgoff_t idx; |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = vma_hugecache_offset(h, vma, address); |
| |
| return find_lock_page(mapping, idx); |
| } |
| |
| /* |
| * Return whether there is a pagecache page to back given address within VMA. |
| * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. |
| */ |
| static bool hugetlbfs_pagecache_present(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address) |
| { |
| struct address_space *mapping; |
| pgoff_t idx; |
| struct page *page; |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = vma_hugecache_offset(h, vma, address); |
| |
| page = find_get_page(mapping, idx); |
| if (page) |
| put_page(page); |
| return page != NULL; |
| } |
| |
| int huge_add_to_page_cache(struct page *page, struct address_space *mapping, |
| pgoff_t idx) |
| { |
| struct inode *inode = mapping->host; |
| struct hstate *h = hstate_inode(inode); |
| int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
| |
| if (err) |
| return err; |
| ClearPagePrivate(page); |
| |
| /* |
| * set page dirty so that it will not be removed from cache/file |
| * by non-hugetlbfs specific code paths. |
| */ |
| set_page_dirty(page); |
| |
| spin_lock(&inode->i_lock); |
| inode->i_blocks += blocks_per_huge_page(h); |
| spin_unlock(&inode->i_lock); |
| return 0; |
| } |
| |
| static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| struct address_space *mapping, pgoff_t idx, |
| unsigned long address, pte_t *ptep, unsigned int flags) |
| { |
| struct hstate *h = hstate_vma(vma); |
| int ret = VM_FAULT_SIGBUS; |
| int anon_rmap = 0; |
| unsigned long size; |
| struct page *page; |
| pte_t new_pte; |
| spinlock_t *ptl; |
| bool new_page = false; |
| |
| /* |
| * Currently, we are forced to kill the process in the event the |
| * original mapper has unmapped pages from the child due to a failed |
| * COW. Warn that such a situation has occurred as it may not be obvious |
| */ |
| if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
| pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n", |
| current->pid); |
| return ret; |
| } |
| |
| /* |
| * Use page lock to guard against racing truncation |
| * before we get page_table_lock. |
| */ |
| retry: |
| page = find_lock_page(mapping, idx); |
| if (!page) { |
| size = i_size_read(mapping->host) >> huge_page_shift(h); |
| if (idx >= size) |
| goto out; |
| |
| /* |
| * Check for page in userfault range |
| */ |
| if (userfaultfd_missing(vma)) { |
| u32 hash; |
| struct vm_fault vmf = { |
| .vma = vma, |
| .address = address, |
| .flags = flags, |
| /* |
| * Hard to debug if it ends up being |
| * used by a callee that assumes |
| * something about the other |
| * uninitialized fields... same as in |
| * memory.c |
| */ |
| }; |
| |
| /* |
| * hugetlb_fault_mutex must be dropped before |
| * handling userfault. Reacquire after handling |
| * fault to make calling code simpler. |
| */ |
| hash = hugetlb_fault_mutex_hash(h, mapping, idx); |
| mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| ret = handle_userfault(&vmf, VM_UFFD_MISSING); |
| mutex_lock(&hugetlb_fault_mutex_table[hash]); |
| goto out; |
| } |
| |
| page = alloc_huge_page(vma, address, 0); |
| if (IS_ERR(page)) { |
| ret = PTR_ERR(page); |
| if (ret == -ENOMEM) |
| ret = VM_FAULT_OOM; |
| else |
| ret = VM_FAULT_SIGBUS; |
| goto out; |
| } |
| clear_huge_page(page, address, pages_per_huge_page(h)); |
| __SetPageUptodate(page); |
| new_page = true; |
| |
| if (vma->vm_flags & VM_MAYSHARE) { |
| int err = huge_add_to_page_cache(page, mapping, idx); |
| if (err) { |
| put_page(page); |
| if (err == -EEXIST) |
| goto retry; |
| goto out; |
| } |
| } else { |
| lock_page(page); |
| if (unlikely(anon_vma_prepare(vma))) { |
| ret = VM_FAULT_OOM; |
| goto backout_unlocked; |
| } |
| anon_rmap = 1; |
| } |
| } else { |
| /* |
| * If memory error occurs between mmap() and fault, some process |
| * don't have hwpoisoned swap entry for errored virtual address. |
| * So we need to block hugepage fault by PG_hwpoison bit check. |
| */ |
| if (unlikely(PageHWPoison(page))) { |
| ret = VM_FAULT_HWPOISON_LARGE | |
| VM_FAULT_SET_HINDEX(hstate_index(h)); |
| goto backout_unlocked; |
| } |
| } |
| |
| /* |
| * If we are going to COW a private mapping later, we examine the |
| * pending reservations for this page now. This will ensure that |
| * any allocations necessary to record that reservation occur outside |
| * the spinlock. |
| */ |
| if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
| if (vma_needs_reservation(h, vma, address) < 0) { |
| ret = VM_FAULT_OOM; |
| goto backout_unlocked; |
| } |
| /* Just decrements count, does not deallocate */ |
| vma_end_reservation(h, vma, address); |
| } |
| |
| ptl = huge_pte_lock(h, mm, ptep); |
| size = i_size_read(mapping->host) >> huge_page_shift(h); |
| if (idx >= size) |
| goto backout; |
| |
| ret = 0; |
| if (!huge_pte_none(huge_ptep_get(ptep))) |
| goto backout; |
| |
| if (anon_rmap) { |
| ClearPagePrivate(page); |
| hugepage_add_new_anon_rmap(page, vma, address); |
| } else |
| page_dup_rmap(page, true); |
| new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
| && (vma->vm_flags & VM_SHARED))); |
| set_huge_pte_at(mm, address, ptep, new_pte); |
| |
| hugetlb_count_add(pages_per_huge_page(h), mm); |
| if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
| /* Optimization, do the COW without a second fault */ |
| ret = hugetlb_cow(mm, vma, address, ptep, page, ptl); |
| } |
| |
| spin_unlock(ptl); |
| |
| /* |
| * Only make newly allocated pages active. Existing pages found |
| * in the pagecache could be !page_huge_active() if they have been |
| * isolated for migration. |
| */ |
| if (new_page) |
| set_page_huge_active(page); |
| |
| unlock_page(page); |
| out: |
| return ret; |
| |
| backout: |
| spin_unlock(ptl); |
| backout_unlocked: |
| unlock_page(page); |
| restore_reserve_on_error(h, vma, address, page); |
| put_page(page); |
| goto out; |
| } |
| |
| #ifdef CONFIG_SMP |
| u32 hugetlb_fault_mutex_hash(struct hstate *h, struct address_space *mapping, |
| pgoff_t idx) |
| { |
| unsigned long key[2]; |
| u32 hash; |
| |
| key[0] = (unsigned long) mapping; |
| key[1] = idx; |
| |
| hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0); |
| |
| return hash & (num_fault_mutexes - 1); |
| } |
| #else |
| /* |
| * For uniprocesor systems we always use a single mutex, so just |
| * return 0 and avoid the hashing overhead. |
| */ |
| u32 hugetlb_fault_mutex_hash(struct hstate *h, struct address_space *mapping, |
| pgoff_t idx) |
| { |
| return 0; |
| } |
| #endif |
| |
| int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, unsigned int flags) |
| { |
| pte_t *ptep, entry; |
| spinlock_t *ptl; |
| int ret; |
| u32 hash; |
| pgoff_t idx; |
| struct page *page = NULL; |
| struct page *pagecache_page = NULL; |
| struct hstate *h = hstate_vma(vma); |
| struct address_space *mapping; |
| int need_wait_lock = 0; |
| |
| address &= huge_page_mask(h); |
| |
| ptep = huge_pte_offset(mm, address, huge_page_size(h)); |
| if (ptep) { |
| entry = huge_ptep_get(ptep); |
| if (unlikely(is_hugetlb_entry_migration(entry))) { |
| migration_entry_wait_huge(vma, mm, ptep); |
| return 0; |
| } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) |
| return VM_FAULT_HWPOISON_LARGE | |
| VM_FAULT_SET_HINDEX(hstate_index(h)); |
| } else { |
| ptep = huge_pte_alloc(mm, vma, address, huge_page_size(h)); |
| if (!ptep) |
| return VM_FAULT_OOM; |
| } |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = vma_hugecache_offset(h, vma, address); |
| |
| /* |
| * Serialize hugepage allocation and instantiation, so that we don't |
| * get spurious allocation failures if two CPUs race to instantiate |
| * the same page in the page cache. |
| */ |
| hash = hugetlb_fault_mutex_hash(h, mapping, idx); |
| mutex_lock(&hugetlb_fault_mutex_table[hash]); |
| |
| entry = huge_ptep_get(ptep); |
| if (huge_pte_none(entry)) { |
| ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags); |
| goto out_mutex; |
| } |
| |
| ret = 0; |
| |
| /* |
| * entry could be a migration/hwpoison entry at this point, so this |
| * check prevents the kernel from going below assuming that we have |
| * a active hugepage in pagecache. This goto expects the 2nd page fault, |
| * and is_hugetlb_entry_(migration|hwpoisoned) check will properly |
| * handle it. |
| */ |
| if (!pte_present(entry)) |
| goto out_mutex; |
| |
| /* |
| * If we are going to COW the mapping later, we examine the pending |
| * reservations for this page now. This will ensure that any |
| * allocations necessary to record that reservation occur outside the |
| * spinlock. For private mappings, we also lookup the pagecache |
| * page now as it is used to determine if a reservation has been |
| * consumed. |
| */ |
| if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { |
| if (vma_needs_reservation(h, vma, address) < 0) { |
| ret = VM_FAULT_OOM; |
| goto out_mutex; |
| } |
| /* Just decrements count, does not deallocate */ |
| vma_end_reservation(h, vma, address); |
| |
| if (!(vma->vm_flags & VM_MAYSHARE)) |
| pagecache_page = hugetlbfs_pagecache_page(h, |
| vma, address); |
| } |
| |
| ptl = huge_pte_lock(h, mm, ptep); |
| |
| /* Check for a racing update before calling hugetlb_cow */ |
| if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) |
| goto out_ptl; |
| |
| /* |
| * hugetlb_cow() requires page locks of pte_page(entry) and |
| * pagecache_page, so here we need take the former one |
| * when page != pagecache_page or !pagecache_page. |
| */ |
| page = pte_page(entry); |
| if (page != pagecache_page) |
| if (!trylock_page(page)) { |
| need_wait_lock = 1; |
| goto out_ptl; |
| } |
| |
| get_page(page); |
| |
| if (flags & FAULT_FLAG_WRITE) { |
| if (!huge_pte_write(entry)) { |
| ret = hugetlb_cow(mm, vma, address, ptep, |
| pagecache_page, ptl); |
| goto out_put_page; |
| } |
| entry = huge_pte_mkdirty(entry); |
| } |
| entry = pte_mkyoung(entry); |
| if (huge_ptep_set_access_flags(vma, address, ptep, entry, |
| flags & FAULT_FLAG_WRITE)) |
| update_mmu_cache(vma, address, ptep); |
| out_put_page: |
| if (page != pagecache_page) |
| unlock_page(page); |
| put_page(page); |
| out_ptl: |
| spin_unlock(ptl); |
| |
| if (pagecache_page) { |
| unlock_page(pagecache_page); |
| put_page(pagecache_page); |
| } |
| out_mutex: |
| mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| /* |
| * Generally it's safe to hold refcount during waiting page lock. But |
| * here we just wait to defer the next page fault to avoid busy loop and |
| * the page is not used after unlocked before returning from the current |
| * page fault. So we are safe from accessing freed page, even if we wait |
| * here without taking refcount. |
| */ |
| if (need_wait_lock) |
| wait_on_page_locked(page); |
| return ret; |
| } |
| |
| /* |
| * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with |
| * modifications for huge pages. |
| */ |
| int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, |
| pte_t *dst_pte, |
| struct vm_area_struct *dst_vma, |
| unsigned long dst_addr, |
| unsigned long src_addr, |
| struct page **pagep) |
| { |
| struct address_space *mapping; |
| pgoff_t idx; |
| unsigned long size; |
| int vm_shared = dst_vma->vm_flags & VM_SHARED; |
| struct hstate *h = hstate_vma(dst_vma); |
| pte_t _dst_pte; |
| spinlock_t *ptl; |
| int ret; |
| struct page *page; |
| |
| if (!*pagep) { |
| /* If a page already exists, then it's UFFDIO_COPY for |
| * a non-missing case. Return -EEXIST. |
| */ |
| if (vm_shared && |
| hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) { |
| ret = -EEXIST; |
| goto out; |
| } |
| |
| page = alloc_huge_page(dst_vma, dst_addr, 0); |
| if (IS_ERR(page)) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| ret = copy_huge_page_from_user(page, |
| (const void __user *) src_addr, |
| pages_per_huge_page(h), false); |
| |
| /* fallback to copy_from_user outside mmap_sem */ |
| if (unlikely(ret)) { |
| ret = -ENOENT; |
| *pagep = page; |
| /* don't free the page */ |
| goto out; |
| } |
| } else { |
| page = *pagep; |
| *pagep = NULL; |
| } |
| |
| /* |
| * The memory barrier inside __SetPageUptodate makes sure that |
| * preceding stores to the page contents become visible before |
| * the set_pte_at() write. |
| */ |
| __SetPageUptodate(page); |
| |
| mapping = dst_vma->vm_file->f_mapping; |
| idx = vma_hugecache_offset(h, dst_vma, dst_addr); |
| |
| /* |
| * If shared, add to page cache |
| */ |
| if (vm_shared) { |
| size = i_size_read(mapping->host) >> huge_page_shift(h); |
| ret = -EFAULT; |
| if (idx >= size) |
| goto out_release_nounlock; |
| |
| /* |
| * Serialization between remove_inode_hugepages() and |
| * huge_add_to_page_cache() below happens through the |
| * hugetlb_fault_mutex_table that here must be hold by |
| * the caller. |
| */ |
| ret = huge_add_to_page_cache(page, mapping, idx); |
| if (ret) |
| goto out_release_nounlock; |
| } |
| |
| ptl = huge_pte_lockptr(h, dst_mm, dst_pte); |
| spin_lock(ptl); |
| |
| /* |
| * Recheck the i_size after holding PT lock to make sure not |
| * to leave any page mapped (as page_mapped()) beyond the end |
| * of the i_size (remove_inode_hugepages() is strict about |
| * enforcing that). If we bail out here, we'll also leave a |
| * page in the radix tree in the vm_shared case beyond the end |
| * of the i_size, but remove_inode_hugepages() will take care |
| * of it as soon as we drop the hugetlb_fault_mutex_table. |
| */ |
| size = i_size_read(mapping->host) >> huge_page_shift(h); |
| ret = -EFAULT; |
| if (idx >= size) |
| goto out_release_unlock; |
| |
| ret = -EEXIST; |
| if (!huge_pte_none(huge_ptep_get(dst_pte))) |
| goto out_release_unlock; |
| |
| if (vm_shared) { |
| page_dup_rmap(page, true); |
| } else { |
| ClearPagePrivate(page); |
| hugepage_add_new_anon_rmap(page, dst_vma, dst_addr); |
| } |
| |
| _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE); |
| if (dst_vma->vm_flags & VM_WRITE) |
| _dst_pte = huge_pte_mkdirty(_dst_pte); |
| _dst_pte = pte_mkyoung(_dst_pte); |
| |
| set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); |
| |
| (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte, |
| dst_vma->vm_flags & VM_WRITE); |
| hugetlb_count_add(pages_per_huge_page(h), dst_mm); |
| |
| /* No need to invalidate - it was non-present before */ |
| update_mmu_cache(dst_vma, dst_addr, dst_pte); |
| |
| spin_unlock(ptl); |
| set_page_huge_active(page); |
| if (vm_shared) |
| unlock_page(page); |
| ret = 0; |
| out: |
| return ret; |
| out_release_unlock: |
| spin_unlock(ptl); |
| if (vm_shared) |
| unlock_page(page); |
| out_release_nounlock: |
| put_page(page); |
| goto out; |
| } |
| |
| long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| struct page **pages, struct vm_area_struct **vmas, |
| unsigned long *position, unsigned long *nr_pages, |
| long i, unsigned int flags, int *nonblocking) |
| { |
| unsigned long pfn_offset; |
| unsigned long vaddr = *position; |
| unsigned long remainder = *nr_pages; |
| struct hstate *h = hstate_vma(vma); |
| int err = -EFAULT; |
| |
| while (vaddr < vma->vm_end && remainder) { |
| pte_t *pte; |
| spinlock_t *ptl = NULL; |
| int absent; |
| struct page *page; |
| |
| /* |
| * If we have a pending SIGKILL, don't keep faulting pages and |
| * potentially allocating memory. |
| */ |
| if (unlikely(fatal_signal_pending(current))) { |
| remainder = 0; |
| break; |
| } |
| |
| /* |
| * Some archs (sparc64, sh*) have multiple pte_ts to |
| * each hugepage. We have to make sure we get the |
| * first, for the page indexing below to work. |
| * |
| * Note that page table lock is not held when pte is null. |
| */ |
| pte = huge_pte_offset(mm, vaddr & huge_page_mask(h), |
| huge_page_size(h)); |
| if (pte) |
| ptl = huge_pte_lock(h, mm, pte); |
| absent = !pte || huge_pte_none(huge_ptep_get(pte)); |
| |
| /* |
| * When coredumping, it suits get_dump_page if we just return |
| * an error where there's an empty slot with no huge pagecache |
| * to back it. This way, we avoid allocating a hugepage, and |
| * the sparse dumpfile avoids allocating disk blocks, but its |
| * huge holes still show up with zeroes where they need to be. |
| */ |
| if (absent && (flags & FOLL_DUMP) && |
| !hugetlbfs_pagecache_present(h, vma, vaddr)) { |
| if (pte) |
| spin_unlock(ptl); |
| remainder = 0; |
| break; |
| } |
| |
| /* |
| * We need call hugetlb_fault for both hugepages under migration |
| * (in which case hugetlb_fault waits for the migration,) and |
| * hwpoisoned hugepages (in which case we need to prevent the |
| * caller from accessing to them.) In order to do this, we use |
| * here is_swap_pte instead of is_hugetlb_entry_migration and |
| * is_hugetlb_entry_hwpoisoned. This is because it simply covers |
| * both cases, and because we can't follow correct pages |
| * directly from any kind of swap entries. |
| */ |
| if (absent || is_swap_pte(huge_ptep_get(pte)) || |
| ((flags & FOLL_WRITE) && |
| !huge_pte_write(huge_ptep_get(pte)))) { |
| int ret; |
| unsigned int fault_flags = 0; |
| |
| if (pte) |
| spin_unlock(ptl); |
| if (flags & FOLL_WRITE) |
| fault_flags |= FAULT_FLAG_WRITE; |
| if (nonblocking) |
| fault_flags |= FAULT_FLAG_ALLOW_RETRY; |
| if (flags & FOLL_NOWAIT) |
| fault_flags |= FAULT_FLAG_ALLOW_RETRY | |
| FAULT_FLAG_RETRY_NOWAIT; |
| if (flags & FOLL_TRIED) { |
| VM_WARN_ON_ONCE(fault_flags & |
| FAULT_FLAG_ALLOW_RETRY); |
| fault_flags |= FAULT_FLAG_TRIED; |
| } |
| ret = hugetlb_fault(mm, vma, vaddr, fault_flags); |
| if (ret & VM_FAULT_ERROR) { |
| err = vm_fault_to_errno(ret, flags); |
| remainder = 0; |
| break; |
| } |
| if (ret & VM_FAULT_RETRY) { |
| if (nonblocking) |
| *nonblocking = 0; |
| *nr_pages = 0; |
| /* |
| * VM_FAULT_RETRY must not return an |
| * error, it will return zero |
| * instead. |
| * |
| * No need to update "position" as the |
| * caller will not check it after |
| * *nr_pages is set to 0. |
| */ |
| return i; |
| } |
| continue; |
| } |
| |
| pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
| page = pte_page(huge_ptep_get(pte)); |
| |
| /* |
| * Instead of doing 'try_get_page()' below in the same_page |
| * loop, just check the count once here. |
| */ |
| if (unlikely(page_count(page) <= 0)) { |
| if (pages) { |
| spin_unlock(ptl); |
| remainder = 0; |
| err = -ENOMEM; |
| break; |
| } |
| } |
| same_page: |
| if (pages) { |
| pages[i] = mem_map_offset(page, pfn_offset); |
| get_page(pages[i]); |
| } |
| |
| if (vmas) |
| vmas[i] = vma; |
| |
| vaddr += PAGE_SIZE; |
| ++pfn_offset; |
| --remainder; |
| ++i; |
| if (vaddr < vma->vm_end && remainder && |
| pfn_offset < pages_per_huge_page(h)) { |
| /* |
| * We use pfn_offset to avoid touching the pageframes |
| * of this compound page. |
| */ |
| goto same_page; |
| } |
| spin_unlock(ptl); |
| } |
| *nr_pages = remainder; |
| /* |
| * setting position is actually required only if remainder is |
| * not zero but it's faster not to add a "if (remainder)" |
| * branch. |
| */ |
| *position = vaddr; |
| |
| return i ? i : err; |
| } |
| |
| #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE |
| /* |
| * ARCHes with special requirements for evicting HUGETLB backing TLB entries can |
| * implement this. |
| */ |
| #define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) |
| #endif |
| |
| unsigned long hugetlb_change_protection(struct vm_area_struct *vma, |
| unsigned long address, unsigned long end, pgprot_t newprot) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long start = address; |
| pte_t *ptep; |
| pte_t pte; |
| struct hstate *h = hstate_vma(vma); |
| unsigned long pages = 0; |
| unsigned long f_start = start; |
| unsigned long f_end = end; |
| bool shared_pmd = false; |
| |
| /* |
| * In the case of shared PMDs, the area to flush could be beyond |
| * start/end. Set f_start/f_end to cover the maximum possible |
| * range if PMD sharing is possible. |
| */ |
| adjust_range_if_pmd_sharing_possible(vma, &f_start, &f_end); |
| |
| BUG_ON(address >= end); |
| flush_cache_range(vma, f_start, f_end); |
| |
| mmu_notifier_invalidate_range_start(mm, f_start, f_end); |
| i_mmap_lock_write(vma->vm_file->f_mapping); |
| for (; address < end; address += huge_page_size(h)) { |
| spinlock_t *ptl; |
| ptep = huge_pte_offset(mm, address, huge_page_size(h)); |
| if (!ptep) |
| continue; |
| ptl = huge_pte_lock(h, mm, ptep); |
| if (huge_pmd_unshare(mm, &address, ptep)) { |
| pages++; |
| spin_unlock(ptl); |
| shared_pmd = true; |
| continue; |
| } |
| pte = huge_ptep_get(ptep); |
| if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { |
| spin_unlock(ptl); |
| continue; |
| } |
| if (unlikely(is_hugetlb_entry_migration(pte))) { |
| swp_entry_t entry = pte_to_swp_entry(pte); |
| |
| if (is_write_migration_entry(entry)) { |
| pte_t newpte; |
| |
| make_migration_entry_read(&entry); |
| newpte = swp_entry_to_pte(entry); |
| set_huge_swap_pte_at(mm, address, ptep, |
| newpte, huge_page_size(h)); |
| pages++; |
| } |
| spin_unlock(ptl); |
| continue; |
| } |
| if (!huge_pte_none(pte)) { |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| pte = pte_mkhuge(huge_pte_modify(pte, newprot)); |
| pte = arch_make_huge_pte(pte, vma, NULL, 0); |
| set_huge_pte_at(mm, address, ptep, pte); |
| pages++; |
| } |
| spin_unlock(ptl); |
| } |
| /* |
| * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare |
| * may have cleared our pud entry and done put_page on the page table: |
| * once we release i_mmap_rwsem, another task can do the final put_page |
| * and that page table be reused and filled with junk. If we actually |
| * did unshare a page of pmds, flush the range corresponding to the pud. |
| */ |
| if (shared_pmd) { |
| flush_hugetlb_tlb_range(vma, f_start, f_end); |
| mmu_notifier_invalidate_range(mm, f_start, f_end); |
| } else { |
| flush_hugetlb_tlb_range(vma, start, end); |
| mmu_notifier_invalidate_range(mm, start, end); |
| } |
| i_mmap_unlock_write(vma->vm_file->f_mapping); |
| mmu_notifier_invalidate_range_end(mm, f_start, f_end); |
| |
| return pages << h->order; |
| } |
| |
| int hugetlb_reserve_pages(struct inode *inode, |
| long from, long to, |
| struct vm_area_struct *vma, |
| vm_flags_t vm_flags) |
| { |
| long ret, chg; |
| struct hstate *h = hstate_inode(inode); |
| struct hugepage_subpool *spool = subpool_inode(inode); |
| struct resv_map *resv_map; |
| long gbl_reserve; |
| |
| /* This should never happen */ |
| if (from > to) { |
| VM_WARN(1, "%s called with a negative range\n", __func__); |
| return -EINVAL; |
| } |
| |
| /* |
| * Only apply hugepage reservation if asked. At fault time, an |
| * attempt will be made for VM_NORESERVE to allocate a page |
| * without using reserves |
| */ |
| if (vm_flags & VM_NORESERVE) |
| return 0; |
| |
| /* |
| * Shared mappings base their reservation on the number of pages that |
| * are already allocated on behalf of the file. Private mappings need |
| * to reserve the full area even if read-only as mprotect() may be |
| * called to make the mapping read-write. Assume !vma is a shm mapping |
| */ |
| if (!vma || vma->vm_flags & VM_MAYSHARE) { |
| resv_map = inode_resv_map(inode); |
| |
| chg = region_chg(resv_map, from, to); |
| |
| } else { |
| resv_map = resv_map_alloc(); |
| if (!resv_map) |
| return -ENOMEM; |
| |
| chg = to - from; |
| |
| set_vma_resv_map(vma, resv_map); |
| set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
| } |
| |
| if (chg < 0) { |
| ret = chg; |
| goto out_err; |
| } |
| |
| /* |
| * There must be enough pages in the subpool for the mapping. If |
| * the subpool has a minimum size, there may be some global |
| * reservations already in place (gbl_reserve). |
| */ |
| gbl_reserve = hugepage_subpool_get_pages(spool, chg); |
| if (gbl_reserve < 0) { |
| ret = -ENOSPC; |
| goto out_err; |
| } |
| |
| /* |
| * Check enough hugepages are available for the reservation. |
| * Hand the pages back to the subpool if there are not |
| */ |
| ret = hugetlb_acct_memory(h, gbl_reserve); |
| if (ret < 0) { |
| /* put back original number of pages, chg */ |
| (void)hugepage_subpool_put_pages(spool, chg); |
| goto out_err; |
| } |
| |
| /* |
| * Account for the reservations made. Shared mappings record regions |
| * that have reservations as they are shared by multiple VMAs. |
| * When the last VMA disappears, the region map says how much |
| * the reservation was and the page cache tells how much of |
| * the reservation was consumed. Private mappings are per-VMA and |
| * only the consumed reservations are tracked. When the VMA |
| * disappears, the original reservation is the VMA size and the |
| * consumed reservations are stored in the map. Hence, nothing |
| * else has to be done for private mappings here |
| */ |
| if (!vma || vma->vm_flags & VM_MAYSHARE) { |
| long add = region_add(resv_map, from, to); |
| |
| if (unlikely(chg > add)) { |
| /* |
| * pages in this range were added to the reserve |
| * map between region_chg and region_add. This |
| * indicates a race with alloc_huge_page. Adjust |
| * the subpool and reserve counts modified above |
| * based on the difference. |
| */ |
| long rsv_adjust; |
| |
| rsv_adjust = hugepage_subpool_put_pages(spool, |
| chg - add); |
| hugetlb_acct_memory(h, -rsv_adjust); |
| } |
| } |
| return 0; |
| out_err: |
| if (!vma || vma->vm_flags & VM_MAYSHARE) |
| /* Don't call region_abort if region_chg failed */ |
| if (chg >= 0) |
| region_abort(resv_map, from, to); |
| if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| kref_put(&resv_map->refs, resv_map_release); |
| return ret; |
| } |
| |
| long hugetlb_unreserve_pages(struct inode *inode, long start, long end, |
| long freed) |
| { |
| struct hstate *h = hstate_inode(inode); |
| struct resv_map *resv_map = inode_resv_map(inode); |
| long chg = 0; |
| struct hugepage_subpool *spool = subpool_inode(inode); |
| long gbl_reserve; |
| |
| if (resv_map) { |
| chg = region_del(resv_map, start, end); |
| /* |
| * region_del() can fail in the rare case where a region |
| * must be split and another region descriptor can not be |
| * allocated. If end == LONG_MAX, it will not fail. |
| */ |
| if (chg < 0) |
| return chg; |
| } |
| |
| spin_lock(&inode->i_lock); |
| inode->i_blocks -= (blocks_per_huge_page(h) * freed); |
| spin_unlock(&inode->i_lock); |
| |
| /* |
| * If the subpool has a minimum size, the number of global |
| * reservations to be released may be adjusted. |
| */ |
| gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed)); |
| hugetlb_acct_memory(h, -gbl_reserve); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE |
| static unsigned long page_table_shareable(struct vm_area_struct *svma, |
| struct vm_area_struct *vma, |
| unsigned long addr, pgoff_t idx) |
| { |
| unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + |
| svma->vm_start; |
| unsigned long sbase = saddr & PUD_MASK; |
| unsigned long s_end = sbase + PUD_SIZE; |
| |
| /* Allow segments to share if only one is marked locked */ |
| unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; |
| unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK; |
| |
| /* |
| * match the virtual addresses, permission and the alignment of the |
| * page table page. |
| */ |
| if (pmd_index(addr) != pmd_index(saddr) || |
| vm_flags != svm_flags || |
| sbase < svma->vm_start || svma->vm_end < s_end) |
| return 0; |
| |
| return saddr; |
| } |
| |
| static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr) |
| { |
| unsigned long base = addr & PUD_MASK; |
| unsigned long end = base + PUD_SIZE; |
| |
| /* |
| * check on proper vm_flags and page table alignment |
| */ |
| if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end)) |
| return true; |
| return false; |
| } |
| |
| bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) |
| { |
| #ifdef CONFIG_USERFAULTFD |
| if (uffd_disable_huge_pmd_share(vma)) |
| return false; |
| #endif |
| return vma_shareable(vma, addr); |
| } |
| |
| /* |
| * Determine if start,end range within vma could be mapped by shared pmd. |
| * If yes, adjust start and end to cover range associated with possible |
| * shared pmd mappings. |
| */ |
| void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, |
| unsigned long *start, unsigned long *end) |
| { |
| unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE), |
| v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE); |
| |
| /* |
| * vma need span at least one aligned PUD size and the start,end range |
| * must at least partialy within it. |
| */ |
| if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) || |
| (*end <= v_start) || (*start >= v_end)) |
| return; |
| |
| /* Extend the range to be PUD aligned for a worst case scenario */ |
| if (*start > v_start) |
| *start = ALIGN_DOWN(*start, PUD_SIZE); |
| |
| if (*end < v_end) |
| *end = ALIGN(*end, PUD_SIZE); |
| } |
| |
| /* |
| * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() |
| * and returns the corresponding pte. While this is not necessary for the |
| * !shared pmd case because we can allocate the pmd later as well, it makes the |
| * code much cleaner. pmd allocation is essential for the shared case because |
| * pud has to be populated inside the same i_mmap_rwsem section - otherwise |
| * racing tasks could either miss the sharing (see huge_pte_offset) or select a |
| * bad pmd for sharing. |
| */ |
| pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long addr, pud_t *pud) |
| { |
| struct address_space *mapping = vma->vm_file->f_mapping; |
| pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + |
| vma->vm_pgoff; |
| struct vm_area_struct *svma; |
| unsigned long saddr; |
| pte_t *spte = NULL; |
| pte_t *pte; |
| spinlock_t *ptl; |
| |
| i_mmap_lock_write(mapping); |
| vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { |
| if (svma == vma) |
| continue; |
| |
| saddr = page_table_shareable(svma, vma, addr, idx); |
| if (saddr) { |
| spte = huge_pte_offset(svma->vm_mm, saddr, |
| vma_mmu_pagesize(svma)); |
| if (spte) { |
| get_page(virt_to_page(spte)); |
| break; |
| } |
| } |
| } |
| |
| if (!spte) |
| goto out; |
| |
| ptl = huge_pte_lock(hstate_vma(vma), mm, spte); |
| if (pud_none(*pud)) { |
| pud_populate(mm, pud, |
| (pmd_t *)((unsigned long)spte & PAGE_MASK)); |
| mm_inc_nr_pmds(mm); |
| } else { |
| put_page(virt_to_page(spte)); |
| } |
| spin_unlock(ptl); |
| out: |
| pte = (pte_t *)pmd_alloc(mm, pud, addr); |
| i_mmap_unlock_write(mapping); |
| return pte; |
| } |
| |
| /* |
| * unmap huge page backed by shared pte. |
| * |
| * Hugetlb pte page is ref counted at the time of mapping. If pte is shared |
| * indicated by page_count > 1, unmap is achieved by clearing pud and |
| * decrementing the ref count. If count == 1, the pte page is not shared. |
| * |
| * called with page table lock held. |
| * |
| * returns: 1 successfully unmapped a shared pte page |
| * 0 the underlying pte page is not shared, or it is the last user |
| */ |
| int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) |
| { |
| pgd_t *pgd = pgd_offset(mm, *addr); |
| p4d_t *p4d = p4d_offset(pgd, *addr); |
| pud_t *pud = pud_offset(p4d, *addr); |
| |
| BUG_ON(page_count(virt_to_page(ptep)) == 0); |
| if (page_count(virt_to_page(ptep)) == 1) |
| return 0; |
| |
| pud_clear(pud); |
| put_page(virt_to_page(ptep)); |
| mm_dec_nr_pmds(mm); |
| /* |
| * This update of passed address optimizes loops sequentially |
| * processing addresses in increments of huge page size (PMD_SIZE |
| * in this case). By clearing the pud, a PUD_SIZE area is unmapped. |
| * Update address to the 'last page' in the cleared area so that |
| * calling loop can move to first page past this area. |
| */ |
| *addr |= PUD_SIZE - PMD_SIZE; |
| return 1; |
| } |
| |
| #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
| pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct vma, |
| unsigned long addr, pud_t *pud) |
| { |
| return NULL; |
| } |
| |
| int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) |
| { |
| return 0; |
| } |
| |
| void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, |
| unsigned long *start, unsigned long *end) |
| { |
| } |
| |
| bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) |
| { |
| return false; |
| } |
| #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
| |
| #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB |
| pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long addr, unsigned long sz) |
| { |
| pgd_t *pgd; |
| p4d_t *p4d; |
| pud_t *pud; |
| pte_t *pte = NULL; |
| |
| pgd = pgd_offset(mm, addr); |
| p4d = p4d_alloc(mm, pgd, addr); |
| if (!p4d) |
| return NULL; |
| pud = pud_alloc(mm, p4d, addr); |
| if (pud) { |
| if (sz == PUD_SIZE) { |
| pte = (pte_t *)pud; |
| } else { |
| BUG_ON(sz != PMD_SIZE); |
| if (want_pmd_share(vma, addr) && pud_none(*pud)) |
| pte = huge_pmd_share(mm, vma, addr, pud); |
| else |
| pte = (pte_t *)pmd_alloc(mm, pud, addr); |
| } |
| } |
| BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte)); |
| |
| return pte; |
| } |
| |
| /* |
| * huge_pte_offset() - Walk the page table to resolve the hugepage |
| * entry at address @addr |
| * |
| * Return: Pointer to page table or swap entry (PUD or PMD) for |
| * address @addr, or NULL if a p*d_none() entry is encountered and the |
| * size @sz doesn't match the hugepage size at this level of the page |
| * table. |
| */ |
| pte_t *huge_pte_offset(struct mm_struct *mm, |
| unsigned long addr, unsigned long sz) |
| { |
| pgd_t *pgd; |
| p4d_t *p4d; |
| pud_t *pud, pud_entry; |
| pmd_t *pmd, pmd_entry; |
| |
| pgd = pgd_offset(mm, addr); |
| if (!pgd_present(*pgd)) |
| return NULL; |
| p4d = p4d_offset(pgd, addr); |
| if (!p4d_present(*p4d)) |
| return NULL; |
| |
| pud = pud_offset(p4d, addr); |
| pud_entry = READ_ONCE(*pud); |
| if (sz != PUD_SIZE && pud_none(pud_entry)) |
| return NULL; |
| /* hugepage or swap? */ |
| if (pud_huge(pud_entry) || !pud_present(pud_entry)) |
| return (pte_t *)pud; |
| |
| pmd = pmd_offset(pud, addr); |
| pmd_entry = READ_ONCE(*pmd); |
| if (sz != PMD_SIZE && pmd_none(pmd_entry)) |
| return NULL; |
| /* hugepage or swap? */ |
| if (pmd_huge(pmd_entry) || !pmd_present(pmd_entry)) |
| return (pte_t *)pmd; |
| |
| return NULL; |
| } |
| |
| #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ |
| |
| /* |
| * These functions are overwritable if your architecture needs its own |
| * behavior. |
| */ |
| struct page * __weak |
| follow_huge_addr(struct mm_struct *mm, unsigned long address, |
| int write) |
| { |
| return ERR_PTR(-EINVAL); |
| } |
| |
| struct page * __weak |
| follow_huge_pd(struct vm_area_struct *vma, |
| unsigned long address, hugepd_t hpd, int flags, int pdshift) |
| { |
| WARN(1, "hugepd follow called with no support for hugepage directory format\n"); |
| return NULL; |
| } |
| |
| struct page * __weak |
| follow_huge_pmd(struct mm_struct *mm, unsigned long address, |
| pmd_t *pmd, int flags) |
| { |
| struct page *page = NULL; |
| spinlock_t *ptl; |
| pte_t pte; |
| retry: |
| ptl = pmd_lockptr(mm, pmd); |
| spin_lock(ptl); |
| /* |
| * make sure that the address range covered by this pmd is not |
| * unmapped from other threads. |
| */ |
| if (!pmd_huge(*pmd)) |
| goto out; |
| pte = huge_ptep_get((pte_t *)pmd); |
| if (pte_present(pte)) { |
| page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT); |
| if (flags & FOLL_GET) |
| get_page(page); |
| } else { |
| if (is_hugetlb_entry_migration(pte)) { |
| spin_unlock(ptl); |
| __migration_entry_wait(mm, (pte_t *)pmd, ptl); |
| goto retry; |
| } |
| /* |
| * hwpoisoned entry is treated as no_page_table in |
| * follow_page_mask(). |
| */ |
| } |
| out: |
| spin_unlock(ptl); |
| return page; |
| } |
| |
| struct page * __weak |
| follow_huge_pud(struct mm_struct *mm, unsigned long address, |
| pud_t *pud, int flags) |
| { |
| if (flags & FOLL_GET) |
| return NULL; |
| |
| return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT); |
| } |
| |
| struct page * __weak |
| follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags) |
| { |
| if (flags & FOLL_GET) |
| return NULL; |
| |
| return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT); |
| } |
| |
| bool isolate_huge_page(struct page *page, struct list_head *list) |
| { |
| bool ret = true; |
| |
| spin_lock(&hugetlb_lock); |
| if (!PageHeadHuge(page) || !page_huge_active(page) || |
| !get_page_unless_zero(page)) { |
| ret = false; |
| goto unlock; |
| } |
| clear_page_huge_active(page); |
| list_move_tail(&page->lru, list); |
| unlock: |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| void putback_active_hugepage(struct page *page) |
| { |
| VM_BUG_ON_PAGE(!PageHead(page), page); |
| spin_lock(&hugetlb_lock); |
| set_page_huge_active(page); |
| list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); |
| spin_unlock(&hugetlb_lock); |
| put_page(page); |
| } |