x86, mm: introduce vmem_altmap to augment vmemmap_populate()
In support of providing struct page for large persistent memory
capacities, use struct vmem_altmap to change the default policy for
allocating memory for the memmap array. The default vmemmap_populate()
allocates page table storage area from the page allocator. Given
persistent memory capacities relative to DRAM it may not be feasible to
store the memmap in 'System Memory'. Instead vmem_altmap represents
pre-allocated "device pages" to satisfy vmemmap_alloc_block_buf()
requests.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 8829482..5488d21 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -30,6 +30,7 @@
#include <linux/module.h>
#include <linux/memory.h>
#include <linux/memory_hotplug.h>
+#include <linux/memremap.h>
#include <linux/nmi.h>
#include <linux/gfp.h>
#include <linux/kcore.h>
@@ -714,6 +715,12 @@
{
unsigned long magic;
unsigned int nr_pages = 1 << order;
+ struct vmem_altmap *altmap = to_vmem_altmap((unsigned long) page);
+
+ if (altmap) {
+ vmem_altmap_free(altmap, nr_pages);
+ return;
+ }
/* bootmem page has reserved flag */
if (PageReserved(page)) {
@@ -1017,13 +1024,19 @@
{
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct page *page = pfn_to_page(start_pfn);
+ struct vmem_altmap *altmap;
struct zone *zone;
int ret;
- zone = page_zone(pfn_to_page(start_pfn));
- kernel_physical_mapping_remove(start, start + size);
+ /* With altmap the first mapped page is offset from @start */
+ altmap = to_vmem_altmap((unsigned long) page);
+ if (altmap)
+ page += vmem_altmap_offset(altmap);
+ zone = page_zone(page);
ret = __remove_pages(zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
+ kernel_physical_mapping_remove(start, start + size);
return ret;
}
@@ -1235,7 +1248,7 @@
static int __meminitdata node_start;
static int __meminit vmemmap_populate_hugepages(unsigned long start,
- unsigned long end, int node)
+ unsigned long end, int node, struct vmem_altmap *altmap)
{
unsigned long addr;
unsigned long next;
@@ -1258,7 +1271,7 @@
if (pmd_none(*pmd)) {
void *p;
- p = vmemmap_alloc_block_buf(PMD_SIZE, node);
+ p = __vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
if (p) {
pte_t entry;
@@ -1279,7 +1292,8 @@
addr_end = addr + PMD_SIZE;
p_end = p + PMD_SIZE;
continue;
- }
+ } else if (altmap)
+ return -ENOMEM; /* no fallback */
} else if (pmd_large(*pmd)) {
vmemmap_verify((pte_t *)pmd, node, addr, next);
continue;
@@ -1293,11 +1307,16 @@
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
{
+ struct vmem_altmap *altmap = to_vmem_altmap(start);
int err;
if (cpu_has_pse)
- err = vmemmap_populate_hugepages(start, end, node);
- else
+ err = vmemmap_populate_hugepages(start, end, node, altmap);
+ else if (altmap) {
+ pr_err_once("%s: no cpu support for altmap allocations\n",
+ __func__);
+ err = -ENOMEM;
+ } else
err = vmemmap_populate_basepages(start, end, node);
if (!err)
sync_global_pgds(start, end - 1, 0);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 904629b..be3f854 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -178,7 +178,8 @@
pmem->pfn_flags = PFN_DEV;
if (pmem_should_map_pages(dev)) {
- pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res);
+ pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res,
+ NULL);
pmem->pfn_flags |= PFN_MAP;
} else
pmem->virt_addr = (void __pmem *) devm_memremap(dev,
@@ -387,7 +388,8 @@
/* establish pfn range for lookup, and switch to direct map */
pmem = dev_get_drvdata(dev);
devm_memunmap(dev, (void __force *) pmem->virt_addr);
- pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res);
+ pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res,
+ NULL);
pmem->pfn_flags |= PFN_MAP;
if (IS_ERR(pmem->virt_addr)) {
rc = PTR_ERR(pmem->virt_addr);
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 2ea574f..4340599 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -275,7 +275,8 @@
extern bool is_memblock_offlined(struct memory_block *mem);
extern void remove_memory(int nid, u64 start, u64 size);
extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn);
-extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
+extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
+ unsigned long map_offset);
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index d90721c..aa3e82a 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -4,21 +4,53 @@
struct resource;
struct device;
+
+/**
+ * struct vmem_altmap - pre-allocated storage for vmemmap_populate
+ * @base_pfn: base of the entire dev_pagemap mapping
+ * @reserve: pages mapped, but reserved for driver use (relative to @base)
+ * @free: free pages set aside in the mapping for memmap storage
+ * @align: pages reserved to meet allocation alignments
+ * @alloc: track pages consumed, private to vmemmap_populate()
+ */
+struct vmem_altmap {
+ const unsigned long base_pfn;
+ const unsigned long reserve;
+ unsigned long free;
+ unsigned long align;
+ unsigned long alloc;
+};
+
+unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
+void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
+
+#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_ZONE_DEVICE)
+struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start);
+#else
+static inline struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
+{
+ return NULL;
+}
+#endif
+
/**
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
+ * @altmap: pre-allocated/reserved memory for vmemmap allocations
* @dev: host device of the mapping for debug
*/
struct dev_pagemap {
- /* TODO: vmem_altmap and percpu_ref count */
+ struct vmem_altmap *altmap;
+ const struct resource *res;
struct device *dev;
};
#ifdef CONFIG_ZONE_DEVICE
-void *devm_memremap_pages(struct device *dev, struct resource *res);
+void *devm_memremap_pages(struct device *dev, struct resource *res,
+ struct vmem_altmap *altmap);
struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
#else
static inline void *devm_memremap_pages(struct device *dev,
- struct resource *res)
+ struct resource *res, struct vmem_altmap *altmap)
{
/*
* Fail attempts to call devm_memremap_pages() without
@@ -34,5 +66,4 @@
return NULL;
}
#endif
-
#endif /* _LINUX_MEMREMAP_H_ */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d9fe12d..8bb0907 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2217,7 +2217,14 @@
pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
void *vmemmap_alloc_block(unsigned long size, int node);
-void *vmemmap_alloc_block_buf(unsigned long size, int node);
+struct vmem_altmap;
+void *__vmemmap_alloc_block_buf(unsigned long size, int node,
+ struct vmem_altmap *altmap);
+static inline void *vmemmap_alloc_block_buf(unsigned long size, int node)
+{
+ return __vmemmap_alloc_block_buf(size, node, NULL);
+}
+
void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
int vmemmap_populate_basepages(unsigned long start, unsigned long end,
int node);
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 61cfbf4..562f647 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -166,6 +166,7 @@
struct resource res;
struct percpu_ref *ref;
struct dev_pagemap pgmap;
+ struct vmem_altmap altmap;
};
static void pgmap_radix_release(struct resource *res)
@@ -183,6 +184,7 @@
struct page_map *page_map = data;
struct resource *res = &page_map->res;
resource_size_t align_start, align_size;
+ struct dev_pagemap *pgmap = &page_map->pgmap;
pgmap_radix_release(res);
@@ -190,6 +192,8 @@
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(resource_size(res), SECTION_SIZE);
arch_remove_memory(align_start, align_size);
+ dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
+ "%s: failed to free all reserved pages\n", __func__);
}
/* assumes rcu_read_lock() held at entry */
@@ -203,11 +207,23 @@
return page_map ? &page_map->pgmap : NULL;
}
-void *devm_memremap_pages(struct device *dev, struct resource *res)
+/**
+ * devm_memremap_pages - remap and provide memmap backing for the given resource
+ * @dev: hosting device for @res
+ * @res: "host memory" address range
+ * @altmap: optional descriptor for allocating the memmap from @res
+ *
+ * Note, the expectation is that @res is a host memory range that could
+ * feasibly be treated as a "System RAM" range, i.e. not a device mmio
+ * range, but this is not enforced.
+ */
+void *devm_memremap_pages(struct device *dev, struct resource *res,
+ struct vmem_altmap *altmap)
{
int is_ram = region_intersects(res->start, resource_size(res),
"System RAM");
resource_size_t key, align_start, align_size;
+ struct dev_pagemap *pgmap;
struct page_map *page_map;
int error, nid;
@@ -220,14 +236,27 @@
if (is_ram == REGION_INTERSECTS)
return __va(res->start);
+ if (altmap && !IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) {
+ dev_err(dev, "%s: altmap requires CONFIG_SPARSEMEM_VMEMMAP=y\n",
+ __func__);
+ return ERR_PTR(-ENXIO);
+ }
+
page_map = devres_alloc_node(devm_memremap_pages_release,
sizeof(*page_map), GFP_KERNEL, dev_to_node(dev));
if (!page_map)
return ERR_PTR(-ENOMEM);
+ pgmap = &page_map->pgmap;
memcpy(&page_map->res, res, sizeof(*res));
- page_map->pgmap.dev = dev;
+ pgmap->dev = dev;
+ if (altmap) {
+ memcpy(&page_map->altmap, altmap, sizeof(*altmap));
+ pgmap->altmap = &page_map->altmap;
+ }
+ pgmap->res = &page_map->res;
+
mutex_lock(&pgmap_lock);
error = 0;
for (key = res->start; key <= res->end; key += SECTION_SIZE) {
@@ -273,4 +302,43 @@
return ERR_PTR(error);
}
EXPORT_SYMBOL(devm_memremap_pages);
+
+unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
+{
+ /* number of pfns from base where pfn_to_page() is valid */
+ return altmap->reserve + altmap->free;
+}
+
+void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
+{
+ altmap->alloc -= nr_pfns;
+}
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
+{
+ /*
+ * 'memmap_start' is the virtual address for the first "struct
+ * page" in this range of the vmemmap array. In the case of
+ * CONFIG_SPARSE_VMEMMAP a page_to_pfn conversion is simple
+ * pointer arithmetic, so we can perform this to_vmem_altmap()
+ * conversion without concern for the initialization state of
+ * the struct page fields.
+ */
+ struct page *page = (struct page *) memmap_start;
+ struct dev_pagemap *pgmap;
+
+ /*
+ * Uncoditionally retrieve a dev_pagemap associated with the
+ * given physical address, this is only for use in the
+ * arch_{add|remove}_memory() for setting up and tearing down
+ * the memmap.
+ */
+ rcu_read_lock();
+ pgmap = find_dev_pagemap(__pfn_to_phys(page_to_pfn(page)));
+ rcu_read_unlock();
+
+ return pgmap ? pgmap->altmap : NULL;
+}
+#endif /* CONFIG_SPARSEMEM_VMEMMAP */
#endif /* CONFIG_ZONE_DEVICE */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 92f9595..4af58a3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -17,6 +17,7 @@
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/memory.h>
+#include <linux/memremap.h>
#include <linux/memory_hotplug.h>
#include <linux/highmem.h>
#include <linux/vmalloc.h>
@@ -506,10 +507,25 @@
unsigned long i;
int err = 0;
int start_sec, end_sec;
+ struct vmem_altmap *altmap;
+
/* during initialize mem_map, align hot-added range to section */
start_sec = pfn_to_section_nr(phys_start_pfn);
end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
+ altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
+ if (altmap) {
+ /*
+ * Validate altmap is within bounds of the total request
+ */
+ if (altmap->base_pfn != phys_start_pfn
+ || vmem_altmap_offset(altmap) > nr_pages) {
+ pr_warn_once("memory add fail, invalid altmap\n");
+ return -EINVAL;
+ }
+ altmap->alloc = 0;
+ }
+
for (i = start_sec; i <= end_sec; i++) {
err = __add_section(nid, zone, section_nr_to_pfn(i));
@@ -731,7 +747,8 @@
pgdat_resize_unlock(zone->zone_pgdat, &flags);
}
-static int __remove_section(struct zone *zone, struct mem_section *ms)
+static int __remove_section(struct zone *zone, struct mem_section *ms,
+ unsigned long map_offset)
{
unsigned long start_pfn;
int scn_nr;
@@ -748,7 +765,7 @@
start_pfn = section_nr_to_pfn(scn_nr);
__remove_zone(zone, start_pfn);
- sparse_remove_one_section(zone, ms);
+ sparse_remove_one_section(zone, ms, map_offset);
return 0;
}
@@ -767,9 +784,32 @@
unsigned long nr_pages)
{
unsigned long i;
- int sections_to_remove;
- resource_size_t start, size;
- int ret = 0;
+ unsigned long map_offset = 0;
+ int sections_to_remove, ret = 0;
+
+ /* In the ZONE_DEVICE case device driver owns the memory region */
+ if (is_dev_zone(zone)) {
+ struct page *page = pfn_to_page(phys_start_pfn);
+ struct vmem_altmap *altmap;
+
+ altmap = to_vmem_altmap((unsigned long) page);
+ if (altmap)
+ map_offset = vmem_altmap_offset(altmap);
+ } else {
+ resource_size_t start, size;
+
+ start = phys_start_pfn << PAGE_SHIFT;
+ size = nr_pages * PAGE_SIZE;
+
+ ret = release_mem_region_adjustable(&iomem_resource, start,
+ size);
+ if (ret) {
+ resource_size_t endres = start + size - 1;
+
+ pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
+ &start, &endres, ret);
+ }
+ }
/*
* We can only remove entire sections
@@ -777,23 +817,12 @@
BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
BUG_ON(nr_pages % PAGES_PER_SECTION);
- start = phys_start_pfn << PAGE_SHIFT;
- size = nr_pages * PAGE_SIZE;
-
- /* in the ZONE_DEVICE case device driver owns the memory region */
- if (!is_dev_zone(zone))
- ret = release_mem_region_adjustable(&iomem_resource, start, size);
- if (ret) {
- resource_size_t endres = start + size - 1;
-
- pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
- &start, &endres, ret);
- }
-
sections_to_remove = nr_pages / PAGES_PER_SECTION;
for (i = 0; i < sections_to_remove; i++) {
unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
- ret = __remove_section(zone, __pfn_to_section(pfn));
+
+ ret = __remove_section(zone, __pfn_to_section(pfn), map_offset);
+ map_offset = 0;
if (ret)
break;
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2540971..7ca3fe6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -43,6 +43,7 @@
#include <linux/vmalloc.h>
#include <linux/vmstat.h>
#include <linux/mempolicy.h>
+#include <linux/memremap.h>
#include <linux/stop_machine.h>
#include <linux/sort.h>
#include <linux/pfn.h>
@@ -4485,8 +4486,9 @@
void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
unsigned long start_pfn, enum memmap_context context)
{
- pg_data_t *pgdat = NODE_DATA(nid);
+ struct vmem_altmap *altmap = to_vmem_altmap(__pfn_to_phys(start_pfn));
unsigned long end_pfn = start_pfn + size;
+ pg_data_t *pgdat = NODE_DATA(nid);
unsigned long pfn;
struct zone *z;
unsigned long nr_initialised = 0;
@@ -4494,6 +4496,13 @@
if (highest_memmap_pfn < end_pfn - 1)
highest_memmap_pfn = end_pfn - 1;
+ /*
+ * Honor reservation requested by the driver for this ZONE_DEVICE
+ * memory
+ */
+ if (altmap && start_pfn == altmap->base_pfn)
+ start_pfn += altmap->reserve;
+
z = &pgdat->node_zones[zone];
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
/*
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 4cba9c27..b60802b 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -20,6 +20,7 @@
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/bootmem.h>
+#include <linux/memremap.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
@@ -70,7 +71,7 @@
}
/* need to make sure size is all the same during early stage */
-void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node)
+static void * __meminit alloc_block_buf(unsigned long size, int node)
{
void *ptr;
@@ -87,6 +88,77 @@
return ptr;
}
+static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
+{
+ return altmap->base_pfn + altmap->reserve + altmap->alloc
+ + altmap->align;
+}
+
+static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
+{
+ unsigned long allocated = altmap->alloc + altmap->align;
+
+ if (altmap->free > allocated)
+ return altmap->free - allocated;
+ return 0;
+}
+
+/**
+ * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation
+ * @altmap - reserved page pool for the allocation
+ * @nr_pfns - size (in pages) of the allocation
+ *
+ * Allocations are aligned to the size of the request
+ */
+static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap,
+ unsigned long nr_pfns)
+{
+ unsigned long pfn = vmem_altmap_next_pfn(altmap);
+ unsigned long nr_align;
+
+ nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
+ nr_align = ALIGN(pfn, nr_align) - pfn;
+
+ if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
+ return ULONG_MAX;
+ altmap->alloc += nr_pfns;
+ altmap->align += nr_align;
+ return pfn + nr_align;
+}
+
+static void * __meminit altmap_alloc_block_buf(unsigned long size,
+ struct vmem_altmap *altmap)
+{
+ unsigned long pfn, nr_pfns;
+ void *ptr;
+
+ if (size & ~PAGE_MASK) {
+ pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
+ __func__, size);
+ return NULL;
+ }
+
+ nr_pfns = size >> PAGE_SHIFT;
+ pfn = vmem_altmap_alloc(altmap, nr_pfns);
+ if (pfn < ULONG_MAX)
+ ptr = __va(__pfn_to_phys(pfn));
+ else
+ ptr = NULL;
+ pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
+ __func__, pfn, altmap->alloc, altmap->align, nr_pfns);
+
+ return ptr;
+}
+
+/* need to make sure size is all the same during early stage */
+void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node,
+ struct vmem_altmap *altmap)
+{
+ if (altmap)
+ return altmap_alloc_block_buf(size, altmap);
+ return alloc_block_buf(size, node);
+}
+
void __meminit vmemmap_verify(pte_t *pte, int node,
unsigned long start, unsigned long end)
{
@@ -103,7 +175,7 @@
pte_t *pte = pte_offset_kernel(pmd, addr);
if (pte_none(*pte)) {
pte_t entry;
- void *p = vmemmap_alloc_block_buf(PAGE_SIZE, node);
+ void *p = alloc_block_buf(PAGE_SIZE, node);
if (!p)
return NULL;
entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
diff --git a/mm/sparse.c b/mm/sparse.c
index d1b48b6..3717cee 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -748,7 +748,7 @@
if (!memmap)
return;
- for (i = 0; i < PAGES_PER_SECTION; i++) {
+ for (i = 0; i < nr_pages; i++) {
if (PageHWPoison(&memmap[i])) {
atomic_long_sub(1, &num_poisoned_pages);
ClearPageHWPoison(&memmap[i]);
@@ -788,7 +788,8 @@
free_map_bootmem(memmap);
}
-void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
+void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
+ unsigned long map_offset)
{
struct page *memmap = NULL;
unsigned long *usemap = NULL, flags;
@@ -804,7 +805,8 @@
}
pgdat_resize_unlock(pgdat, &flags);
- clear_hwpoisoned_pages(memmap, PAGES_PER_SECTION);
+ clear_hwpoisoned_pages(memmap + map_offset,
+ PAGES_PER_SECTION - map_offset);
free_section_usemap(memmap, usemap);
}
#endif /* CONFIG_MEMORY_HOTREMOVE */