| /* |
| * kernel/cpuset.c |
| * |
| * Processor and Memory placement constraints for sets of tasks. |
| * |
| * Copyright (C) 2003 BULL SA. |
| * Copyright (C) 2004-2007 Silicon Graphics, Inc. |
| * Copyright (C) 2006 Google, Inc |
| * |
| * Portions derived from Patrick Mochel's sysfs code. |
| * sysfs is Copyright (c) 2001-3 Patrick Mochel |
| * |
| * 2003-10-10 Written by Simon Derr. |
| * 2003-10-22 Updates by Stephen Hemminger. |
| * 2004 May-July Rework by Paul Jackson. |
| * 2006 Rework by Paul Menage to use generic cgroups |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file COPYING in the main directory of the Linux |
| * distribution for more details. |
| */ |
| |
| #include <linux/cpu.h> |
| #include <linux/cpumask.h> |
| #include <linux/cpuset.h> |
| #include <linux/err.h> |
| #include <linux/errno.h> |
| #include <linux/file.h> |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| #include <linux/kernel.h> |
| #include <linux/kmod.h> |
| #include <linux/list.h> |
| #include <linux/mempolicy.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/mount.h> |
| #include <linux/namei.h> |
| #include <linux/pagemap.h> |
| #include <linux/prio_heap.h> |
| #include <linux/proc_fs.h> |
| #include <linux/rcupdate.h> |
| #include <linux/sched.h> |
| #include <linux/seq_file.h> |
| #include <linux/security.h> |
| #include <linux/slab.h> |
| #include <linux/spinlock.h> |
| #include <linux/stat.h> |
| #include <linux/string.h> |
| #include <linux/time.h> |
| #include <linux/backing-dev.h> |
| #include <linux/sort.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/atomic.h> |
| #include <linux/mutex.h> |
| #include <linux/kfifo.h> |
| |
| /* |
| * Tracks how many cpusets are currently defined in system. |
| * When there is only one cpuset (the root cpuset) we can |
| * short circuit some hooks. |
| */ |
| int number_of_cpusets __read_mostly; |
| |
| /* Retrieve the cpuset from a cgroup */ |
| struct cgroup_subsys cpuset_subsys; |
| struct cpuset; |
| |
| /* See "Frequency meter" comments, below. */ |
| |
| struct fmeter { |
| int cnt; /* unprocessed events count */ |
| int val; /* most recent output value */ |
| time_t time; /* clock (secs) when val computed */ |
| spinlock_t lock; /* guards read or write of above */ |
| }; |
| |
| struct cpuset { |
| struct cgroup_subsys_state css; |
| |
| unsigned long flags; /* "unsigned long" so bitops work */ |
| cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */ |
| nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */ |
| |
| struct cpuset *parent; /* my parent */ |
| |
| /* |
| * Copy of global cpuset_mems_generation as of the most |
| * recent time this cpuset changed its mems_allowed. |
| */ |
| int mems_generation; |
| |
| struct fmeter fmeter; /* memory_pressure filter */ |
| |
| /* partition number for rebuild_sched_domains() */ |
| int pn; |
| }; |
| |
| /* Retrieve the cpuset for a cgroup */ |
| static inline struct cpuset *cgroup_cs(struct cgroup *cont) |
| { |
| return container_of(cgroup_subsys_state(cont, cpuset_subsys_id), |
| struct cpuset, css); |
| } |
| |
| /* Retrieve the cpuset for a task */ |
| static inline struct cpuset *task_cs(struct task_struct *task) |
| { |
| return container_of(task_subsys_state(task, cpuset_subsys_id), |
| struct cpuset, css); |
| } |
| |
| |
| /* bits in struct cpuset flags field */ |
| typedef enum { |
| CS_CPU_EXCLUSIVE, |
| CS_MEM_EXCLUSIVE, |
| CS_MEMORY_MIGRATE, |
| CS_SCHED_LOAD_BALANCE, |
| CS_SPREAD_PAGE, |
| CS_SPREAD_SLAB, |
| } cpuset_flagbits_t; |
| |
| /* convenient tests for these bits */ |
| static inline int is_cpu_exclusive(const struct cpuset *cs) |
| { |
| return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); |
| } |
| |
| static inline int is_mem_exclusive(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); |
| } |
| |
| static inline int is_sched_load_balance(const struct cpuset *cs) |
| { |
| return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
| } |
| |
| static inline int is_memory_migrate(const struct cpuset *cs) |
| { |
| return test_bit(CS_MEMORY_MIGRATE, &cs->flags); |
| } |
| |
| static inline int is_spread_page(const struct cpuset *cs) |
| { |
| return test_bit(CS_SPREAD_PAGE, &cs->flags); |
| } |
| |
| static inline int is_spread_slab(const struct cpuset *cs) |
| { |
| return test_bit(CS_SPREAD_SLAB, &cs->flags); |
| } |
| |
| /* |
| * Increment this integer everytime any cpuset changes its |
| * mems_allowed value. Users of cpusets can track this generation |
| * number, and avoid having to lock and reload mems_allowed unless |
| * the cpuset they're using changes generation. |
| * |
| * A single, global generation is needed because attach_task() could |
| * reattach a task to a different cpuset, which must not have its |
| * generation numbers aliased with those of that tasks previous cpuset. |
| * |
| * Generations are needed for mems_allowed because one task cannot |
| * modify anothers memory placement. So we must enable every task, |
| * on every visit to __alloc_pages(), to efficiently check whether |
| * its current->cpuset->mems_allowed has changed, requiring an update |
| * of its current->mems_allowed. |
| * |
| * Since cpuset_mems_generation is guarded by manage_mutex, |
| * there is no need to mark it atomic. |
| */ |
| static int cpuset_mems_generation; |
| |
| static struct cpuset top_cpuset = { |
| .flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)), |
| .cpus_allowed = CPU_MASK_ALL, |
| .mems_allowed = NODE_MASK_ALL, |
| }; |
| |
| /* |
| * We have two global cpuset mutexes below. They can nest. |
| * It is ok to first take manage_mutex, then nest callback_mutex. We also |
| * require taking task_lock() when dereferencing a tasks cpuset pointer. |
| * See "The task_lock() exception", at the end of this comment. |
| * |
| * A task must hold both mutexes to modify cpusets. If a task |
| * holds manage_mutex, then it blocks others wanting that mutex, |
| * ensuring that it is the only task able to also acquire callback_mutex |
| * and be able to modify cpusets. It can perform various checks on |
| * the cpuset structure first, knowing nothing will change. It can |
| * also allocate memory while just holding manage_mutex. While it is |
| * performing these checks, various callback routines can briefly |
| * acquire callback_mutex to query cpusets. Once it is ready to make |
| * the changes, it takes callback_mutex, blocking everyone else. |
| * |
| * Calls to the kernel memory allocator can not be made while holding |
| * callback_mutex, as that would risk double tripping on callback_mutex |
| * from one of the callbacks into the cpuset code from within |
| * __alloc_pages(). |
| * |
| * If a task is only holding callback_mutex, then it has read-only |
| * access to cpusets. |
| * |
| * The task_struct fields mems_allowed and mems_generation may only |
| * be accessed in the context of that task, so require no locks. |
| * |
| * Any task can increment and decrement the count field without lock. |
| * So in general, code holding manage_mutex or callback_mutex can't rely |
| * on the count field not changing. However, if the count goes to |
| * zero, then only attach_task(), which holds both mutexes, can |
| * increment it again. Because a count of zero means that no tasks |
| * are currently attached, therefore there is no way a task attached |
| * to that cpuset can fork (the other way to increment the count). |
| * So code holding manage_mutex or callback_mutex can safely assume that |
| * if the count is zero, it will stay zero. Similarly, if a task |
| * holds manage_mutex or callback_mutex on a cpuset with zero count, it |
| * knows that the cpuset won't be removed, as cpuset_rmdir() needs |
| * both of those mutexes. |
| * |
| * The cpuset_common_file_write handler for operations that modify |
| * the cpuset hierarchy holds manage_mutex across the entire operation, |
| * single threading all such cpuset modifications across the system. |
| * |
| * The cpuset_common_file_read() handlers only hold callback_mutex across |
| * small pieces of code, such as when reading out possibly multi-word |
| * cpumasks and nodemasks. |
| * |
| * The fork and exit callbacks cpuset_fork() and cpuset_exit(), don't |
| * (usually) take either mutex. These are the two most performance |
| * critical pieces of code here. The exception occurs on cpuset_exit(), |
| * when a task in a notify_on_release cpuset exits. Then manage_mutex |
| * is taken, and if the cpuset count is zero, a usermode call made |
| * to /sbin/cpuset_release_agent with the name of the cpuset (path |
| * relative to the root of cpuset file system) as the argument. |
| * |
| * A cpuset can only be deleted if both its 'count' of using tasks |
| * is zero, and its list of 'children' cpusets is empty. Since all |
| * tasks in the system use _some_ cpuset, and since there is always at |
| * least one task in the system (init), therefore, top_cpuset |
| * always has either children cpusets and/or using tasks. So we don't |
| * need a special hack to ensure that top_cpuset cannot be deleted. |
| * |
| * The above "Tale of Two Semaphores" would be complete, but for: |
| * |
| * The task_lock() exception |
| * |
| * The need for this exception arises from the action of attach_task(), |
| * which overwrites one tasks cpuset pointer with another. It does |
| * so using both mutexes, however there are several performance |
| * critical places that need to reference task->cpuset without the |
| * expense of grabbing a system global mutex. Therefore except as |
| * noted below, when dereferencing or, as in attach_task(), modifying |
| * a tasks cpuset pointer we use task_lock(), which acts on a spinlock |
| * (task->alloc_lock) already in the task_struct routinely used for |
| * such matters. |
| * |
| * P.S. One more locking exception. RCU is used to guard the |
| * update of a tasks cpuset pointer by attach_task() and the |
| * access of task->cpuset->mems_generation via that pointer in |
| * the routine cpuset_update_task_memory_state(). |
| */ |
| |
| static DEFINE_MUTEX(callback_mutex); |
| |
| /* This is ugly, but preserves the userspace API for existing cpuset |
| * users. If someone tries to mount the "cpuset" filesystem, we |
| * silently switch it to mount "cgroup" instead */ |
| static int cpuset_get_sb(struct file_system_type *fs_type, |
| int flags, const char *unused_dev_name, |
| void *data, struct vfsmount *mnt) |
| { |
| struct file_system_type *cgroup_fs = get_fs_type("cgroup"); |
| int ret = -ENODEV; |
| if (cgroup_fs) { |
| char mountopts[] = |
| "cpuset,noprefix," |
| "release_agent=/sbin/cpuset_release_agent"; |
| ret = cgroup_fs->get_sb(cgroup_fs, flags, |
| unused_dev_name, mountopts, mnt); |
| put_filesystem(cgroup_fs); |
| } |
| return ret; |
| } |
| |
| static struct file_system_type cpuset_fs_type = { |
| .name = "cpuset", |
| .get_sb = cpuset_get_sb, |
| }; |
| |
| /* |
| * Return in *pmask the portion of a cpusets's cpus_allowed that |
| * are online. If none are online, walk up the cpuset hierarchy |
| * until we find one that does have some online cpus. If we get |
| * all the way to the top and still haven't found any online cpus, |
| * return cpu_online_map. Or if passed a NULL cs from an exit'ing |
| * task, return cpu_online_map. |
| * |
| * One way or another, we guarantee to return some non-empty subset |
| * of cpu_online_map. |
| * |
| * Call with callback_mutex held. |
| */ |
| |
| static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask) |
| { |
| while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map)) |
| cs = cs->parent; |
| if (cs) |
| cpus_and(*pmask, cs->cpus_allowed, cpu_online_map); |
| else |
| *pmask = cpu_online_map; |
| BUG_ON(!cpus_intersects(*pmask, cpu_online_map)); |
| } |
| |
| /* |
| * Return in *pmask the portion of a cpusets's mems_allowed that |
| * are online, with memory. If none are online with memory, walk |
| * up the cpuset hierarchy until we find one that does have some |
| * online mems. If we get all the way to the top and still haven't |
| * found any online mems, return node_states[N_HIGH_MEMORY]. |
| * |
| * One way or another, we guarantee to return some non-empty subset |
| * of node_states[N_HIGH_MEMORY]. |
| * |
| * Call with callback_mutex held. |
| */ |
| |
| static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask) |
| { |
| while (cs && !nodes_intersects(cs->mems_allowed, |
| node_states[N_HIGH_MEMORY])) |
| cs = cs->parent; |
| if (cs) |
| nodes_and(*pmask, cs->mems_allowed, |
| node_states[N_HIGH_MEMORY]); |
| else |
| *pmask = node_states[N_HIGH_MEMORY]; |
| BUG_ON(!nodes_intersects(*pmask, node_states[N_HIGH_MEMORY])); |
| } |
| |
| /** |
| * cpuset_update_task_memory_state - update task memory placement |
| * |
| * If the current tasks cpusets mems_allowed changed behind our |
| * backs, update current->mems_allowed, mems_generation and task NUMA |
| * mempolicy to the new value. |
| * |
| * Task mempolicy is updated by rebinding it relative to the |
| * current->cpuset if a task has its memory placement changed. |
| * Do not call this routine if in_interrupt(). |
| * |
| * Call without callback_mutex or task_lock() held. May be |
| * called with or without manage_mutex held. Thanks in part to |
| * 'the_top_cpuset_hack', the tasks cpuset pointer will never |
| * be NULL. This routine also might acquire callback_mutex and |
| * current->mm->mmap_sem during call. |
| * |
| * Reading current->cpuset->mems_generation doesn't need task_lock |
| * to guard the current->cpuset derefence, because it is guarded |
| * from concurrent freeing of current->cpuset by attach_task(), |
| * using RCU. |
| * |
| * The rcu_dereference() is technically probably not needed, |
| * as I don't actually mind if I see a new cpuset pointer but |
| * an old value of mems_generation. However this really only |
| * matters on alpha systems using cpusets heavily. If I dropped |
| * that rcu_dereference(), it would save them a memory barrier. |
| * For all other arch's, rcu_dereference is a no-op anyway, and for |
| * alpha systems not using cpusets, another planned optimization, |
| * avoiding the rcu critical section for tasks in the root cpuset |
| * which is statically allocated, so can't vanish, will make this |
| * irrelevant. Better to use RCU as intended, than to engage in |
| * some cute trick to save a memory barrier that is impossible to |
| * test, for alpha systems using cpusets heavily, which might not |
| * even exist. |
| * |
| * This routine is needed to update the per-task mems_allowed data, |
| * within the tasks context, when it is trying to allocate memory |
| * (in various mm/mempolicy.c routines) and notices that some other |
| * task has been modifying its cpuset. |
| */ |
| |
| void cpuset_update_task_memory_state(void) |
| { |
| int my_cpusets_mem_gen; |
| struct task_struct *tsk = current; |
| struct cpuset *cs; |
| |
| if (task_cs(tsk) == &top_cpuset) { |
| /* Don't need rcu for top_cpuset. It's never freed. */ |
| my_cpusets_mem_gen = top_cpuset.mems_generation; |
| } else { |
| rcu_read_lock(); |
| my_cpusets_mem_gen = task_cs(current)->mems_generation; |
| rcu_read_unlock(); |
| } |
| |
| if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) { |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| cs = task_cs(tsk); /* Maybe changed when task not locked */ |
| guarantee_online_mems(cs, &tsk->mems_allowed); |
| tsk->cpuset_mems_generation = cs->mems_generation; |
| if (is_spread_page(cs)) |
| tsk->flags |= PF_SPREAD_PAGE; |
| else |
| tsk->flags &= ~PF_SPREAD_PAGE; |
| if (is_spread_slab(cs)) |
| tsk->flags |= PF_SPREAD_SLAB; |
| else |
| tsk->flags &= ~PF_SPREAD_SLAB; |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| mpol_rebind_task(tsk, &tsk->mems_allowed); |
| } |
| } |
| |
| /* |
| * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? |
| * |
| * One cpuset is a subset of another if all its allowed CPUs and |
| * Memory Nodes are a subset of the other, and its exclusive flags |
| * are only set if the other's are set. Call holding manage_mutex. |
| */ |
| |
| static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) |
| { |
| return cpus_subset(p->cpus_allowed, q->cpus_allowed) && |
| nodes_subset(p->mems_allowed, q->mems_allowed) && |
| is_cpu_exclusive(p) <= is_cpu_exclusive(q) && |
| is_mem_exclusive(p) <= is_mem_exclusive(q); |
| } |
| |
| /* |
| * validate_change() - Used to validate that any proposed cpuset change |
| * follows the structural rules for cpusets. |
| * |
| * If we replaced the flag and mask values of the current cpuset |
| * (cur) with those values in the trial cpuset (trial), would |
| * our various subset and exclusive rules still be valid? Presumes |
| * manage_mutex held. |
| * |
| * 'cur' is the address of an actual, in-use cpuset. Operations |
| * such as list traversal that depend on the actual address of the |
| * cpuset in the list must use cur below, not trial. |
| * |
| * 'trial' is the address of bulk structure copy of cur, with |
| * perhaps one or more of the fields cpus_allowed, mems_allowed, |
| * or flags changed to new, trial values. |
| * |
| * Return 0 if valid, -errno if not. |
| */ |
| |
| static int validate_change(const struct cpuset *cur, const struct cpuset *trial) |
| { |
| struct cgroup *cont; |
| struct cpuset *c, *par; |
| |
| /* Each of our child cpusets must be a subset of us */ |
| list_for_each_entry(cont, &cur->css.cgroup->children, sibling) { |
| if (!is_cpuset_subset(cgroup_cs(cont), trial)) |
| return -EBUSY; |
| } |
| |
| /* Remaining checks don't apply to root cpuset */ |
| if (cur == &top_cpuset) |
| return 0; |
| |
| par = cur->parent; |
| |
| /* We must be a subset of our parent cpuset */ |
| if (!is_cpuset_subset(trial, par)) |
| return -EACCES; |
| |
| /* If either I or some sibling (!= me) is exclusive, we can't overlap */ |
| list_for_each_entry(cont, &par->css.cgroup->children, sibling) { |
| c = cgroup_cs(cont); |
| if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && |
| c != cur && |
| cpus_intersects(trial->cpus_allowed, c->cpus_allowed)) |
| return -EINVAL; |
| if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && |
| c != cur && |
| nodes_intersects(trial->mems_allowed, c->mems_allowed)) |
| return -EINVAL; |
| } |
| |
| /* Cpusets with tasks can't have empty cpus_allowed or mems_allowed */ |
| if (cgroup_task_count(cur->css.cgroup)) { |
| if (cpus_empty(trial->cpus_allowed) || |
| nodes_empty(trial->mems_allowed)) { |
| return -ENOSPC; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Helper routine for rebuild_sched_domains(). |
| * Do cpusets a, b have overlapping cpus_allowed masks? |
| */ |
| |
| static int cpusets_overlap(struct cpuset *a, struct cpuset *b) |
| { |
| return cpus_intersects(a->cpus_allowed, b->cpus_allowed); |
| } |
| |
| /* |
| * rebuild_sched_domains() |
| * |
| * If the flag 'sched_load_balance' of any cpuset with non-empty |
| * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset |
| * which has that flag enabled, or if any cpuset with a non-empty |
| * 'cpus' is removed, then call this routine to rebuild the |
| * scheduler's dynamic sched domains. |
| * |
| * This routine builds a partial partition of the systems CPUs |
| * (the set of non-overlappping cpumask_t's in the array 'part' |
| * below), and passes that partial partition to the kernel/sched.c |
| * partition_sched_domains() routine, which will rebuild the |
| * schedulers load balancing domains (sched domains) as specified |
| * by that partial partition. A 'partial partition' is a set of |
| * non-overlapping subsets whose union is a subset of that set. |
| * |
| * See "What is sched_load_balance" in Documentation/cpusets.txt |
| * for a background explanation of this. |
| * |
| * Does not return errors, on the theory that the callers of this |
| * routine would rather not worry about failures to rebuild sched |
| * domains when operating in the severe memory shortage situations |
| * that could cause allocation failures below. |
| * |
| * Call with cgroup_mutex held. May take callback_mutex during |
| * call due to the kfifo_alloc() and kmalloc() calls. May nest |
| * a call to the lock_cpu_hotplug()/unlock_cpu_hotplug() pair. |
| * Must not be called holding callback_mutex, because we must not |
| * call lock_cpu_hotplug() while holding callback_mutex. Elsewhere |
| * the kernel nests callback_mutex inside lock_cpu_hotplug() calls. |
| * So the reverse nesting would risk an ABBA deadlock. |
| * |
| * The three key local variables below are: |
| * q - a kfifo queue of cpuset pointers, used to implement a |
| * top-down scan of all cpusets. This scan loads a pointer |
| * to each cpuset marked is_sched_load_balance into the |
| * array 'csa'. For our purposes, rebuilding the schedulers |
| * sched domains, we can ignore !is_sched_load_balance cpusets. |
| * csa - (for CpuSet Array) Array of pointers to all the cpusets |
| * that need to be load balanced, for convenient iterative |
| * access by the subsequent code that finds the best partition, |
| * i.e the set of domains (subsets) of CPUs such that the |
| * cpus_allowed of every cpuset marked is_sched_load_balance |
| * is a subset of one of these domains, while there are as |
| * many such domains as possible, each as small as possible. |
| * doms - Conversion of 'csa' to an array of cpumasks, for passing to |
| * the kernel/sched.c routine partition_sched_domains() in a |
| * convenient format, that can be easily compared to the prior |
| * value to determine what partition elements (sched domains) |
| * were changed (added or removed.) |
| * |
| * Finding the best partition (set of domains): |
| * The triple nested loops below over i, j, k scan over the |
| * load balanced cpusets (using the array of cpuset pointers in |
| * csa[]) looking for pairs of cpusets that have overlapping |
| * cpus_allowed, but which don't have the same 'pn' partition |
| * number and gives them in the same partition number. It keeps |
| * looping on the 'restart' label until it can no longer find |
| * any such pairs. |
| * |
| * The union of the cpus_allowed masks from the set of |
| * all cpusets having the same 'pn' value then form the one |
| * element of the partition (one sched domain) to be passed to |
| * partition_sched_domains(). |
| */ |
| |
| static void rebuild_sched_domains(void) |
| { |
| struct kfifo *q; /* queue of cpusets to be scanned */ |
| struct cpuset *cp; /* scans q */ |
| struct cpuset **csa; /* array of all cpuset ptrs */ |
| int csn; /* how many cpuset ptrs in csa so far */ |
| int i, j, k; /* indices for partition finding loops */ |
| cpumask_t *doms; /* resulting partition; i.e. sched domains */ |
| int ndoms; /* number of sched domains in result */ |
| int nslot; /* next empty doms[] cpumask_t slot */ |
| |
| q = NULL; |
| csa = NULL; |
| doms = NULL; |
| |
| /* Special case for the 99% of systems with one, full, sched domain */ |
| if (is_sched_load_balance(&top_cpuset)) { |
| ndoms = 1; |
| doms = kmalloc(sizeof(cpumask_t), GFP_KERNEL); |
| if (!doms) |
| goto rebuild; |
| *doms = top_cpuset.cpus_allowed; |
| goto rebuild; |
| } |
| |
| q = kfifo_alloc(number_of_cpusets * sizeof(cp), GFP_KERNEL, NULL); |
| if (IS_ERR(q)) |
| goto done; |
| csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL); |
| if (!csa) |
| goto done; |
| csn = 0; |
| |
| cp = &top_cpuset; |
| __kfifo_put(q, (void *)&cp, sizeof(cp)); |
| while (__kfifo_get(q, (void *)&cp, sizeof(cp))) { |
| struct cgroup *cont; |
| struct cpuset *child; /* scans child cpusets of cp */ |
| if (is_sched_load_balance(cp)) |
| csa[csn++] = cp; |
| list_for_each_entry(cont, &cp->css.cgroup->children, sibling) { |
| child = cgroup_cs(cont); |
| __kfifo_put(q, (void *)&child, sizeof(cp)); |
| } |
| } |
| |
| for (i = 0; i < csn; i++) |
| csa[i]->pn = i; |
| ndoms = csn; |
| |
| restart: |
| /* Find the best partition (set of sched domains) */ |
| for (i = 0; i < csn; i++) { |
| struct cpuset *a = csa[i]; |
| int apn = a->pn; |
| |
| for (j = 0; j < csn; j++) { |
| struct cpuset *b = csa[j]; |
| int bpn = b->pn; |
| |
| if (apn != bpn && cpusets_overlap(a, b)) { |
| for (k = 0; k < csn; k++) { |
| struct cpuset *c = csa[k]; |
| |
| if (c->pn == bpn) |
| c->pn = apn; |
| } |
| ndoms--; /* one less element */ |
| goto restart; |
| } |
| } |
| } |
| |
| /* Convert <csn, csa> to <ndoms, doms> */ |
| doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL); |
| if (!doms) |
| goto rebuild; |
| |
| for (nslot = 0, i = 0; i < csn; i++) { |
| struct cpuset *a = csa[i]; |
| int apn = a->pn; |
| |
| if (apn >= 0) { |
| cpumask_t *dp = doms + nslot; |
| |
| if (nslot == ndoms) { |
| static int warnings = 10; |
| if (warnings) { |
| printk(KERN_WARNING |
| "rebuild_sched_domains confused:" |
| " nslot %d, ndoms %d, csn %d, i %d," |
| " apn %d\n", |
| nslot, ndoms, csn, i, apn); |
| warnings--; |
| } |
| continue; |
| } |
| |
| cpus_clear(*dp); |
| for (j = i; j < csn; j++) { |
| struct cpuset *b = csa[j]; |
| |
| if (apn == b->pn) { |
| cpus_or(*dp, *dp, b->cpus_allowed); |
| b->pn = -1; |
| } |
| } |
| nslot++; |
| } |
| } |
| BUG_ON(nslot != ndoms); |
| |
| rebuild: |
| /* Have scheduler rebuild sched domains */ |
| lock_cpu_hotplug(); |
| partition_sched_domains(ndoms, doms); |
| unlock_cpu_hotplug(); |
| |
| done: |
| if (q && !IS_ERR(q)) |
| kfifo_free(q); |
| kfree(csa); |
| /* Don't kfree(doms) -- partition_sched_domains() does that. */ |
| } |
| |
| static inline int started_after_time(struct task_struct *t1, |
| struct timespec *time, |
| struct task_struct *t2) |
| { |
| int start_diff = timespec_compare(&t1->start_time, time); |
| if (start_diff > 0) { |
| return 1; |
| } else if (start_diff < 0) { |
| return 0; |
| } else { |
| /* |
| * Arbitrarily, if two processes started at the same |
| * time, we'll say that the lower pointer value |
| * started first. Note that t2 may have exited by now |
| * so this may not be a valid pointer any longer, but |
| * that's fine - it still serves to distinguish |
| * between two tasks started (effectively) |
| * simultaneously. |
| */ |
| return t1 > t2; |
| } |
| } |
| |
| static inline int started_after(void *p1, void *p2) |
| { |
| struct task_struct *t1 = p1; |
| struct task_struct *t2 = p2; |
| return started_after_time(t1, &t2->start_time, t2); |
| } |
| |
| /* |
| * Call with manage_mutex held. May take callback_mutex during call. |
| */ |
| |
| static int update_cpumask(struct cpuset *cs, char *buf) |
| { |
| struct cpuset trialcs; |
| int retval, i; |
| int is_load_balanced; |
| struct cgroup_iter it; |
| struct cgroup *cgrp = cs->css.cgroup; |
| struct task_struct *p, *dropped; |
| /* Never dereference latest_task, since it's not refcounted */ |
| struct task_struct *latest_task = NULL; |
| struct ptr_heap heap; |
| struct timespec latest_time = { 0, 0 }; |
| |
| /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */ |
| if (cs == &top_cpuset) |
| return -EACCES; |
| |
| trialcs = *cs; |
| |
| /* |
| * An empty cpus_allowed is ok iff there are no tasks in the cpuset. |
| * Since cpulist_parse() fails on an empty mask, we special case |
| * that parsing. The validate_change() call ensures that cpusets |
| * with tasks have cpus. |
| */ |
| buf = strstrip(buf); |
| if (!*buf) { |
| cpus_clear(trialcs.cpus_allowed); |
| } else { |
| retval = cpulist_parse(buf, trialcs.cpus_allowed); |
| if (retval < 0) |
| return retval; |
| } |
| cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map); |
| retval = validate_change(cs, &trialcs); |
| if (retval < 0) |
| return retval; |
| |
| /* Nothing to do if the cpus didn't change */ |
| if (cpus_equal(cs->cpus_allowed, trialcs.cpus_allowed)) |
| return 0; |
| retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after); |
| if (retval) |
| return retval; |
| |
| is_load_balanced = is_sched_load_balance(&trialcs); |
| |
| mutex_lock(&callback_mutex); |
| cs->cpus_allowed = trialcs.cpus_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| again: |
| /* |
| * Scan tasks in the cpuset, and update the cpumasks of any |
| * that need an update. Since we can't call set_cpus_allowed() |
| * while holding tasklist_lock, gather tasks to be processed |
| * in a heap structure. If the statically-sized heap fills up, |
| * overflow tasks that started later, and in future iterations |
| * only consider tasks that started after the latest task in |
| * the previous pass. This guarantees forward progress and |
| * that we don't miss any tasks |
| */ |
| heap.size = 0; |
| cgroup_iter_start(cgrp, &it); |
| while ((p = cgroup_iter_next(cgrp, &it))) { |
| /* Only affect tasks that don't have the right cpus_allowed */ |
| if (cpus_equal(p->cpus_allowed, cs->cpus_allowed)) |
| continue; |
| /* |
| * Only process tasks that started after the last task |
| * we processed |
| */ |
| if (!started_after_time(p, &latest_time, latest_task)) |
| continue; |
| dropped = heap_insert(&heap, p); |
| if (dropped == NULL) { |
| get_task_struct(p); |
| } else if (dropped != p) { |
| get_task_struct(p); |
| put_task_struct(dropped); |
| } |
| } |
| cgroup_iter_end(cgrp, &it); |
| if (heap.size) { |
| for (i = 0; i < heap.size; i++) { |
| struct task_struct *p = heap.ptrs[i]; |
| if (i == 0) { |
| latest_time = p->start_time; |
| latest_task = p; |
| } |
| set_cpus_allowed(p, cs->cpus_allowed); |
| put_task_struct(p); |
| } |
| /* |
| * If we had to process any tasks at all, scan again |
| * in case some of them were in the middle of forking |
| * children that didn't notice the new cpumask |
| * restriction. Not the most efficient way to do it, |
| * but it avoids having to take callback_mutex in the |
| * fork path |
| */ |
| goto again; |
| } |
| heap_free(&heap); |
| if (is_load_balanced) |
| rebuild_sched_domains(); |
| |
| return 0; |
| } |
| |
| /* |
| * cpuset_migrate_mm |
| * |
| * Migrate memory region from one set of nodes to another. |
| * |
| * Temporarilly set tasks mems_allowed to target nodes of migration, |
| * so that the migration code can allocate pages on these nodes. |
| * |
| * Call holding manage_mutex, so our current->cpuset won't change |
| * during this call, as manage_mutex holds off any attach_task() |
| * calls. Therefore we don't need to take task_lock around the |
| * call to guarantee_online_mems(), as we know no one is changing |
| * our tasks cpuset. |
| * |
| * Hold callback_mutex around the two modifications of our tasks |
| * mems_allowed to synchronize with cpuset_mems_allowed(). |
| * |
| * While the mm_struct we are migrating is typically from some |
| * other task, the task_struct mems_allowed that we are hacking |
| * is for our current task, which must allocate new pages for that |
| * migrating memory region. |
| * |
| * We call cpuset_update_task_memory_state() before hacking |
| * our tasks mems_allowed, so that we are assured of being in |
| * sync with our tasks cpuset, and in particular, callbacks to |
| * cpuset_update_task_memory_state() from nested page allocations |
| * won't see any mismatch of our cpuset and task mems_generation |
| * values, so won't overwrite our hacked tasks mems_allowed |
| * nodemask. |
| */ |
| |
| static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, |
| const nodemask_t *to) |
| { |
| struct task_struct *tsk = current; |
| |
| cpuset_update_task_memory_state(); |
| |
| mutex_lock(&callback_mutex); |
| tsk->mems_allowed = *to; |
| mutex_unlock(&callback_mutex); |
| |
| do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL); |
| |
| mutex_lock(&callback_mutex); |
| guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed); |
| mutex_unlock(&callback_mutex); |
| } |
| |
| /* |
| * Handle user request to change the 'mems' memory placement |
| * of a cpuset. Needs to validate the request, update the |
| * cpusets mems_allowed and mems_generation, and for each |
| * task in the cpuset, rebind any vma mempolicies and if |
| * the cpuset is marked 'memory_migrate', migrate the tasks |
| * pages to the new memory. |
| * |
| * Call with manage_mutex held. May take callback_mutex during call. |
| * Will take tasklist_lock, scan tasklist for tasks in cpuset cs, |
| * lock each such tasks mm->mmap_sem, scan its vma's and rebind |
| * their mempolicies to the cpusets new mems_allowed. |
| */ |
| |
| static void *cpuset_being_rebound; |
| |
| static int update_nodemask(struct cpuset *cs, char *buf) |
| { |
| struct cpuset trialcs; |
| nodemask_t oldmem; |
| struct task_struct *p; |
| struct mm_struct **mmarray; |
| int i, n, ntasks; |
| int migrate; |
| int fudge; |
| int retval; |
| struct cgroup_iter it; |
| |
| /* |
| * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY]; |
| * it's read-only |
| */ |
| if (cs == &top_cpuset) |
| return -EACCES; |
| |
| trialcs = *cs; |
| |
| /* |
| * An empty mems_allowed is ok iff there are no tasks in the cpuset. |
| * Since nodelist_parse() fails on an empty mask, we special case |
| * that parsing. The validate_change() call ensures that cpusets |
| * with tasks have memory. |
| */ |
| buf = strstrip(buf); |
| if (!*buf) { |
| nodes_clear(trialcs.mems_allowed); |
| } else { |
| retval = nodelist_parse(buf, trialcs.mems_allowed); |
| if (retval < 0) |
| goto done; |
| } |
| nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, |
| node_states[N_HIGH_MEMORY]); |
| oldmem = cs->mems_allowed; |
| if (nodes_equal(oldmem, trialcs.mems_allowed)) { |
| retval = 0; /* Too easy - nothing to do */ |
| goto done; |
| } |
| retval = validate_change(cs, &trialcs); |
| if (retval < 0) |
| goto done; |
| |
| mutex_lock(&callback_mutex); |
| cs->mems_allowed = trialcs.mems_allowed; |
| cs->mems_generation = cpuset_mems_generation++; |
| mutex_unlock(&callback_mutex); |
| |
| cpuset_being_rebound = cs; /* causes mpol_copy() rebind */ |
| |
| fudge = 10; /* spare mmarray[] slots */ |
| fudge += cpus_weight(cs->cpus_allowed); /* imagine one fork-bomb/cpu */ |
| retval = -ENOMEM; |
| |
| /* |
| * Allocate mmarray[] to hold mm reference for each task |
| * in cpuset cs. Can't kmalloc GFP_KERNEL while holding |
| * tasklist_lock. We could use GFP_ATOMIC, but with a |
| * few more lines of code, we can retry until we get a big |
| * enough mmarray[] w/o using GFP_ATOMIC. |
| */ |
| while (1) { |
| ntasks = cgroup_task_count(cs->css.cgroup); /* guess */ |
| ntasks += fudge; |
| mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL); |
| if (!mmarray) |
| goto done; |
| read_lock(&tasklist_lock); /* block fork */ |
| if (cgroup_task_count(cs->css.cgroup) <= ntasks) |
| break; /* got enough */ |
| read_unlock(&tasklist_lock); /* try again */ |
| kfree(mmarray); |
| } |
| |
| n = 0; |
| |
| /* Load up mmarray[] with mm reference for each task in cpuset. */ |
| cgroup_iter_start(cs->css.cgroup, &it); |
| while ((p = cgroup_iter_next(cs->css.cgroup, &it))) { |
| struct mm_struct *mm; |
| |
| if (n >= ntasks) { |
| printk(KERN_WARNING |
| "Cpuset mempolicy rebind incomplete.\n"); |
| break; |
| } |
| mm = get_task_mm(p); |
| if (!mm) |
| continue; |
| mmarray[n++] = mm; |
| } |
| cgroup_iter_end(cs->css.cgroup, &it); |
| read_unlock(&tasklist_lock); |
| |
| /* |
| * Now that we've dropped the tasklist spinlock, we can |
| * rebind the vma mempolicies of each mm in mmarray[] to their |
| * new cpuset, and release that mm. The mpol_rebind_mm() |
| * call takes mmap_sem, which we couldn't take while holding |
| * tasklist_lock. Forks can happen again now - the mpol_copy() |
| * cpuset_being_rebound check will catch such forks, and rebind |
| * their vma mempolicies too. Because we still hold the global |
| * cpuset manage_mutex, we know that no other rebind effort will |
| * be contending for the global variable cpuset_being_rebound. |
| * It's ok if we rebind the same mm twice; mpol_rebind_mm() |
| * is idempotent. Also migrate pages in each mm to new nodes. |
| */ |
| migrate = is_memory_migrate(cs); |
| for (i = 0; i < n; i++) { |
| struct mm_struct *mm = mmarray[i]; |
| |
| mpol_rebind_mm(mm, &cs->mems_allowed); |
| if (migrate) |
| cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed); |
| mmput(mm); |
| } |
| |
| /* We're done rebinding vma's to this cpusets new mems_allowed. */ |
| kfree(mmarray); |
| cpuset_being_rebound = NULL; |
| retval = 0; |
| done: |
| return retval; |
| } |
| |
| int current_cpuset_is_being_rebound(void) |
| { |
| return task_cs(current) == cpuset_being_rebound; |
| } |
| |
| /* |
| * Call with manage_mutex held. |
| */ |
| |
| static int update_memory_pressure_enabled(struct cpuset *cs, char *buf) |
| { |
| if (simple_strtoul(buf, NULL, 10) != 0) |
| cpuset_memory_pressure_enabled = 1; |
| else |
| cpuset_memory_pressure_enabled = 0; |
| return 0; |
| } |
| |
| /* |
| * update_flag - read a 0 or a 1 in a file and update associated flag |
| * bit: the bit to update (CS_CPU_EXCLUSIVE, CS_MEM_EXCLUSIVE, |
| * CS_SCHED_LOAD_BALANCE, |
| * CS_NOTIFY_ON_RELEASE, CS_MEMORY_MIGRATE, |
| * CS_SPREAD_PAGE, CS_SPREAD_SLAB) |
| * cs: the cpuset to update |
| * buf: the buffer where we read the 0 or 1 |
| * |
| * Call with manage_mutex held. |
| */ |
| |
| static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, char *buf) |
| { |
| int turning_on; |
| struct cpuset trialcs; |
| int err; |
| int cpus_nonempty, balance_flag_changed; |
| |
| turning_on = (simple_strtoul(buf, NULL, 10) != 0); |
| |
| trialcs = *cs; |
| if (turning_on) |
| set_bit(bit, &trialcs.flags); |
| else |
| clear_bit(bit, &trialcs.flags); |
| |
| err = validate_change(cs, &trialcs); |
| if (err < 0) |
| return err; |
| |
| cpus_nonempty = !cpus_empty(trialcs.cpus_allowed); |
| balance_flag_changed = (is_sched_load_balance(cs) != |
| is_sched_load_balance(&trialcs)); |
| |
| mutex_lock(&callback_mutex); |
| cs->flags = trialcs.flags; |
| mutex_unlock(&callback_mutex); |
| |
| if (cpus_nonempty && balance_flag_changed) |
| rebuild_sched_domains(); |
| |
| return 0; |
| } |
| |
| /* |
| * Frequency meter - How fast is some event occurring? |
| * |
| * These routines manage a digitally filtered, constant time based, |
| * event frequency meter. There are four routines: |
| * fmeter_init() - initialize a frequency meter. |
| * fmeter_markevent() - called each time the event happens. |
| * fmeter_getrate() - returns the recent rate of such events. |
| * fmeter_update() - internal routine used to update fmeter. |
| * |
| * A common data structure is passed to each of these routines, |
| * which is used to keep track of the state required to manage the |
| * frequency meter and its digital filter. |
| * |
| * The filter works on the number of events marked per unit time. |
| * The filter is single-pole low-pass recursive (IIR). The time unit |
| * is 1 second. Arithmetic is done using 32-bit integers scaled to |
| * simulate 3 decimal digits of precision (multiplied by 1000). |
| * |
| * With an FM_COEF of 933, and a time base of 1 second, the filter |
| * has a half-life of 10 seconds, meaning that if the events quit |
| * happening, then the rate returned from the fmeter_getrate() |
| * will be cut in half each 10 seconds, until it converges to zero. |
| * |
| * It is not worth doing a real infinitely recursive filter. If more |
| * than FM_MAXTICKS ticks have elapsed since the last filter event, |
| * just compute FM_MAXTICKS ticks worth, by which point the level |
| * will be stable. |
| * |
| * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid |
| * arithmetic overflow in the fmeter_update() routine. |
| * |
| * Given the simple 32 bit integer arithmetic used, this meter works |
| * best for reporting rates between one per millisecond (msec) and |
| * one per 32 (approx) seconds. At constant rates faster than one |
| * per msec it maxes out at values just under 1,000,000. At constant |
| * rates between one per msec, and one per second it will stabilize |
| * to a value N*1000, where N is the rate of events per second. |
| * At constant rates between one per second and one per 32 seconds, |
| * it will be choppy, moving up on the seconds that have an event, |
| * and then decaying until the next event. At rates slower than |
| * about one in 32 seconds, it decays all the way back to zero between |
| * each event. |
| */ |
| |
| #define FM_COEF 933 /* coefficient for half-life of 10 secs */ |
| #define FM_MAXTICKS ((time_t)99) /* useless computing more ticks than this */ |
| #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ |
| #define FM_SCALE 1000 /* faux fixed point scale */ |
| |
| /* Initialize a frequency meter */ |
| static void fmeter_init(struct fmeter *fmp) |
| { |
| fmp->cnt = 0; |
| fmp->val = 0; |
| fmp->time = 0; |
| spin_lock_init(&fmp->lock); |
| } |
| |
| /* Internal meter update - process cnt events and update value */ |
| static void fmeter_update(struct fmeter *fmp) |
| { |
| time_t now = get_seconds(); |
| time_t ticks = now - fmp->time; |
| |
| if (ticks == 0) |
| return; |
| |
| ticks = min(FM_MAXTICKS, ticks); |
| while (ticks-- > 0) |
| fmp->val = (FM_COEF * fmp->val) / FM_SCALE; |
| fmp->time = now; |
| |
| fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; |
| fmp->cnt = 0; |
| } |
| |
| /* Process any previous ticks, then bump cnt by one (times scale). */ |
| static void fmeter_markevent(struct fmeter *fmp) |
| { |
| spin_lock(&fmp->lock); |
| fmeter_update(fmp); |
| fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); |
| spin_unlock(&fmp->lock); |
| } |
| |
| /* Process any previous ticks, then return current value. */ |
| static int fmeter_getrate(struct fmeter *fmp) |
| { |
| int val; |
| |
| spin_lock(&fmp->lock); |
| fmeter_update(fmp); |
| val = fmp->val; |
| spin_unlock(&fmp->lock); |
| return val; |
| } |
| |
| static int cpuset_can_attach(struct cgroup_subsys *ss, |
| struct cgroup *cont, struct task_struct *tsk) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| |
| if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)) |
| return -ENOSPC; |
| |
| return security_task_setscheduler(tsk, 0, NULL); |
| } |
| |
| static void cpuset_attach(struct cgroup_subsys *ss, |
| struct cgroup *cont, struct cgroup *oldcont, |
| struct task_struct *tsk) |
| { |
| cpumask_t cpus; |
| nodemask_t from, to; |
| struct mm_struct *mm; |
| struct cpuset *cs = cgroup_cs(cont); |
| struct cpuset *oldcs = cgroup_cs(oldcont); |
| |
| mutex_lock(&callback_mutex); |
| guarantee_online_cpus(cs, &cpus); |
| set_cpus_allowed(tsk, cpus); |
| mutex_unlock(&callback_mutex); |
| |
| from = oldcs->mems_allowed; |
| to = cs->mems_allowed; |
| mm = get_task_mm(tsk); |
| if (mm) { |
| mpol_rebind_mm(mm, &to); |
| if (is_memory_migrate(cs)) |
| cpuset_migrate_mm(mm, &from, &to); |
| mmput(mm); |
| } |
| |
| } |
| |
| /* The various types of files and directories in a cpuset file system */ |
| |
| typedef enum { |
| FILE_MEMORY_MIGRATE, |
| FILE_CPULIST, |
| FILE_MEMLIST, |
| FILE_CPU_EXCLUSIVE, |
| FILE_MEM_EXCLUSIVE, |
| FILE_SCHED_LOAD_BALANCE, |
| FILE_MEMORY_PRESSURE_ENABLED, |
| FILE_MEMORY_PRESSURE, |
| FILE_SPREAD_PAGE, |
| FILE_SPREAD_SLAB, |
| } cpuset_filetype_t; |
| |
| static ssize_t cpuset_common_file_write(struct cgroup *cont, |
| struct cftype *cft, |
| struct file *file, |
| const char __user *userbuf, |
| size_t nbytes, loff_t *unused_ppos) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| cpuset_filetype_t type = cft->private; |
| char *buffer; |
| int retval = 0; |
| |
| /* Crude upper limit on largest legitimate cpulist user might write. */ |
| if (nbytes > 100U + 6 * max(NR_CPUS, MAX_NUMNODES)) |
| return -E2BIG; |
| |
| /* +1 for nul-terminator */ |
| if ((buffer = kmalloc(nbytes + 1, GFP_KERNEL)) == 0) |
| return -ENOMEM; |
| |
| if (copy_from_user(buffer, userbuf, nbytes)) { |
| retval = -EFAULT; |
| goto out1; |
| } |
| buffer[nbytes] = 0; /* nul-terminate */ |
| |
| cgroup_lock(); |
| |
| if (cgroup_is_removed(cont)) { |
| retval = -ENODEV; |
| goto out2; |
| } |
| |
| switch (type) { |
| case FILE_CPULIST: |
| retval = update_cpumask(cs, buffer); |
| break; |
| case FILE_MEMLIST: |
| retval = update_nodemask(cs, buffer); |
| break; |
| case FILE_CPU_EXCLUSIVE: |
| retval = update_flag(CS_CPU_EXCLUSIVE, cs, buffer); |
| break; |
| case FILE_MEM_EXCLUSIVE: |
| retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer); |
| break; |
| case FILE_SCHED_LOAD_BALANCE: |
| retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, buffer); |
| break; |
| case FILE_MEMORY_MIGRATE: |
| retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer); |
| break; |
| case FILE_MEMORY_PRESSURE_ENABLED: |
| retval = update_memory_pressure_enabled(cs, buffer); |
| break; |
| case FILE_MEMORY_PRESSURE: |
| retval = -EACCES; |
| break; |
| case FILE_SPREAD_PAGE: |
| retval = update_flag(CS_SPREAD_PAGE, cs, buffer); |
| cs->mems_generation = cpuset_mems_generation++; |
| break; |
| case FILE_SPREAD_SLAB: |
| retval = update_flag(CS_SPREAD_SLAB, cs, buffer); |
| cs->mems_generation = cpuset_mems_generation++; |
| break; |
| default: |
| retval = -EINVAL; |
| goto out2; |
| } |
| |
| if (retval == 0) |
| retval = nbytes; |
| out2: |
| cgroup_unlock(); |
| out1: |
| kfree(buffer); |
| return retval; |
| } |
| |
| /* |
| * These ascii lists should be read in a single call, by using a user |
| * buffer large enough to hold the entire map. If read in smaller |
| * chunks, there is no guarantee of atomicity. Since the display format |
| * used, list of ranges of sequential numbers, is variable length, |
| * and since these maps can change value dynamically, one could read |
| * gibberish by doing partial reads while a list was changing. |
| * A single large read to a buffer that crosses a page boundary is |
| * ok, because the result being copied to user land is not recomputed |
| * across a page fault. |
| */ |
| |
| static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs) |
| { |
| cpumask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| mask = cs->cpus_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| return cpulist_scnprintf(page, PAGE_SIZE, mask); |
| } |
| |
| static int cpuset_sprintf_memlist(char *page, struct cpuset *cs) |
| { |
| nodemask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| mask = cs->mems_allowed; |
| mutex_unlock(&callback_mutex); |
| |
| return nodelist_scnprintf(page, PAGE_SIZE, mask); |
| } |
| |
| static ssize_t cpuset_common_file_read(struct cgroup *cont, |
| struct cftype *cft, |
| struct file *file, |
| char __user *buf, |
| size_t nbytes, loff_t *ppos) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| cpuset_filetype_t type = cft->private; |
| char *page; |
| ssize_t retval = 0; |
| char *s; |
| |
| if (!(page = (char *)__get_free_page(GFP_TEMPORARY))) |
| return -ENOMEM; |
| |
| s = page; |
| |
| switch (type) { |
| case FILE_CPULIST: |
| s += cpuset_sprintf_cpulist(s, cs); |
| break; |
| case FILE_MEMLIST: |
| s += cpuset_sprintf_memlist(s, cs); |
| break; |
| case FILE_CPU_EXCLUSIVE: |
| *s++ = is_cpu_exclusive(cs) ? '1' : '0'; |
| break; |
| case FILE_MEM_EXCLUSIVE: |
| *s++ = is_mem_exclusive(cs) ? '1' : '0'; |
| break; |
| case FILE_SCHED_LOAD_BALANCE: |
| *s++ = is_sched_load_balance(cs) ? '1' : '0'; |
| break; |
| case FILE_MEMORY_MIGRATE: |
| *s++ = is_memory_migrate(cs) ? '1' : '0'; |
| break; |
| case FILE_MEMORY_PRESSURE_ENABLED: |
| *s++ = cpuset_memory_pressure_enabled ? '1' : '0'; |
| break; |
| case FILE_MEMORY_PRESSURE: |
| s += sprintf(s, "%d", fmeter_getrate(&cs->fmeter)); |
| break; |
| case FILE_SPREAD_PAGE: |
| *s++ = is_spread_page(cs) ? '1' : '0'; |
| break; |
| case FILE_SPREAD_SLAB: |
| *s++ = is_spread_slab(cs) ? '1' : '0'; |
| break; |
| default: |
| retval = -EINVAL; |
| goto out; |
| } |
| *s++ = '\n'; |
| |
| retval = simple_read_from_buffer(buf, nbytes, ppos, page, s - page); |
| out: |
| free_page((unsigned long)page); |
| return retval; |
| } |
| |
| |
| |
| |
| |
| /* |
| * for the common functions, 'private' gives the type of file |
| */ |
| |
| static struct cftype cft_cpus = { |
| .name = "cpus", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_CPULIST, |
| }; |
| |
| static struct cftype cft_mems = { |
| .name = "mems", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_MEMLIST, |
| }; |
| |
| static struct cftype cft_cpu_exclusive = { |
| .name = "cpu_exclusive", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_CPU_EXCLUSIVE, |
| }; |
| |
| static struct cftype cft_mem_exclusive = { |
| .name = "mem_exclusive", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_MEM_EXCLUSIVE, |
| }; |
| |
| static struct cftype cft_sched_load_balance = { |
| .name = "sched_load_balance", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_SCHED_LOAD_BALANCE, |
| }; |
| |
| static struct cftype cft_memory_migrate = { |
| .name = "memory_migrate", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_MEMORY_MIGRATE, |
| }; |
| |
| static struct cftype cft_memory_pressure_enabled = { |
| .name = "memory_pressure_enabled", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_MEMORY_PRESSURE_ENABLED, |
| }; |
| |
| static struct cftype cft_memory_pressure = { |
| .name = "memory_pressure", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_MEMORY_PRESSURE, |
| }; |
| |
| static struct cftype cft_spread_page = { |
| .name = "memory_spread_page", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_SPREAD_PAGE, |
| }; |
| |
| static struct cftype cft_spread_slab = { |
| .name = "memory_spread_slab", |
| .read = cpuset_common_file_read, |
| .write = cpuset_common_file_write, |
| .private = FILE_SPREAD_SLAB, |
| }; |
| |
| static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont) |
| { |
| int err; |
| |
| if ((err = cgroup_add_file(cont, ss, &cft_cpus)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_mems)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_cpu_exclusive)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_mem_exclusive)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_memory_migrate)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_sched_load_balance)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0) |
| return err; |
| if ((err = cgroup_add_file(cont, ss, &cft_spread_slab)) < 0) |
| return err; |
| /* memory_pressure_enabled is in root cpuset only */ |
| if (err == 0 && !cont->parent) |
| err = cgroup_add_file(cont, ss, |
| &cft_memory_pressure_enabled); |
| return 0; |
| } |
| |
| /* |
| * post_clone() is called at the end of cgroup_clone(). |
| * 'cgroup' was just created automatically as a result of |
| * a cgroup_clone(), and the current task is about to |
| * be moved into 'cgroup'. |
| * |
| * Currently we refuse to set up the cgroup - thereby |
| * refusing the task to be entered, and as a result refusing |
| * the sys_unshare() or clone() which initiated it - if any |
| * sibling cpusets have exclusive cpus or mem. |
| * |
| * If this becomes a problem for some users who wish to |
| * allow that scenario, then cpuset_post_clone() could be |
| * changed to grant parent->cpus_allowed-sibling_cpus_exclusive |
| * (and likewise for mems) to the new cgroup. |
| */ |
| static void cpuset_post_clone(struct cgroup_subsys *ss, |
| struct cgroup *cgroup) |
| { |
| struct cgroup *parent, *child; |
| struct cpuset *cs, *parent_cs; |
| |
| parent = cgroup->parent; |
| list_for_each_entry(child, &parent->children, sibling) { |
| cs = cgroup_cs(child); |
| if (is_mem_exclusive(cs) || is_cpu_exclusive(cs)) |
| return; |
| } |
| cs = cgroup_cs(cgroup); |
| parent_cs = cgroup_cs(parent); |
| |
| cs->mems_allowed = parent_cs->mems_allowed; |
| cs->cpus_allowed = parent_cs->cpus_allowed; |
| return; |
| } |
| |
| /* |
| * cpuset_create - create a cpuset |
| * parent: cpuset that will be parent of the new cpuset. |
| * name: name of the new cpuset. Will be strcpy'ed. |
| * mode: mode to set on new inode |
| * |
| * Must be called with the mutex on the parent inode held |
| */ |
| |
| static struct cgroup_subsys_state *cpuset_create( |
| struct cgroup_subsys *ss, |
| struct cgroup *cont) |
| { |
| struct cpuset *cs; |
| struct cpuset *parent; |
| |
| if (!cont->parent) { |
| /* This is early initialization for the top cgroup */ |
| top_cpuset.mems_generation = cpuset_mems_generation++; |
| return &top_cpuset.css; |
| } |
| parent = cgroup_cs(cont->parent); |
| cs = kmalloc(sizeof(*cs), GFP_KERNEL); |
| if (!cs) |
| return ERR_PTR(-ENOMEM); |
| |
| cpuset_update_task_memory_state(); |
| cs->flags = 0; |
| if (is_spread_page(parent)) |
| set_bit(CS_SPREAD_PAGE, &cs->flags); |
| if (is_spread_slab(parent)) |
| set_bit(CS_SPREAD_SLAB, &cs->flags); |
| set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
| cs->cpus_allowed = CPU_MASK_NONE; |
| cs->mems_allowed = NODE_MASK_NONE; |
| cs->mems_generation = cpuset_mems_generation++; |
| fmeter_init(&cs->fmeter); |
| |
| cs->parent = parent; |
| number_of_cpusets++; |
| return &cs->css ; |
| } |
| |
| /* |
| * Locking note on the strange update_flag() call below: |
| * |
| * If the cpuset being removed has its flag 'sched_load_balance' |
| * enabled, then simulate turning sched_load_balance off, which |
| * will call rebuild_sched_domains(). The lock_cpu_hotplug() |
| * call in rebuild_sched_domains() must not be made while holding |
| * callback_mutex. Elsewhere the kernel nests callback_mutex inside |
| * lock_cpu_hotplug() calls. So the reverse nesting would risk an |
| * ABBA deadlock. |
| */ |
| |
| static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont) |
| { |
| struct cpuset *cs = cgroup_cs(cont); |
| |
| cpuset_update_task_memory_state(); |
| |
| if (is_sched_load_balance(cs)) |
| update_flag(CS_SCHED_LOAD_BALANCE, cs, "0"); |
| |
| number_of_cpusets--; |
| kfree(cs); |
| } |
| |
| struct cgroup_subsys cpuset_subsys = { |
| .name = "cpuset", |
| .create = cpuset_create, |
| .destroy = cpuset_destroy, |
| .can_attach = cpuset_can_attach, |
| .attach = cpuset_attach, |
| .populate = cpuset_populate, |
| .post_clone = cpuset_post_clone, |
| .subsys_id = cpuset_subsys_id, |
| .early_init = 1, |
| }; |
| |
| /* |
| * cpuset_init_early - just enough so that the calls to |
| * cpuset_update_task_memory_state() in early init code |
| * are harmless. |
| */ |
| |
| int __init cpuset_init_early(void) |
| { |
| top_cpuset.mems_generation = cpuset_mems_generation++; |
| return 0; |
| } |
| |
| |
| /** |
| * cpuset_init - initialize cpusets at system boot |
| * |
| * Description: Initialize top_cpuset and the cpuset internal file system, |
| **/ |
| |
| int __init cpuset_init(void) |
| { |
| int err = 0; |
| |
| top_cpuset.cpus_allowed = CPU_MASK_ALL; |
| top_cpuset.mems_allowed = NODE_MASK_ALL; |
| |
| fmeter_init(&top_cpuset.fmeter); |
| top_cpuset.mems_generation = cpuset_mems_generation++; |
| set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); |
| |
| err = register_filesystem(&cpuset_fs_type); |
| if (err < 0) |
| return err; |
| |
| number_of_cpusets = 1; |
| return 0; |
| } |
| |
| /* |
| * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs |
| * or memory nodes, we need to walk over the cpuset hierarchy, |
| * removing that CPU or node from all cpusets. If this removes the |
| * last CPU or node from a cpuset, then the guarantee_online_cpus() |
| * or guarantee_online_mems() code will use that emptied cpusets |
| * parent online CPUs or nodes. Cpusets that were already empty of |
| * CPUs or nodes are left empty. |
| * |
| * This routine is intentionally inefficient in a couple of regards. |
| * It will check all cpusets in a subtree even if the top cpuset of |
| * the subtree has no offline CPUs or nodes. It checks both CPUs and |
| * nodes, even though the caller could have been coded to know that |
| * only one of CPUs or nodes needed to be checked on a given call. |
| * This was done to minimize text size rather than cpu cycles. |
| * |
| * Call with both manage_mutex and callback_mutex held. |
| * |
| * Recursive, on depth of cpuset subtree. |
| */ |
| |
| static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur) |
| { |
| struct cgroup *cont; |
| struct cpuset *c; |
| |
| /* Each of our child cpusets mems must be online */ |
| list_for_each_entry(cont, &cur->css.cgroup->children, sibling) { |
| c = cgroup_cs(cont); |
| guarantee_online_cpus_mems_in_subtree(c); |
| if (!cpus_empty(c->cpus_allowed)) |
| guarantee_online_cpus(c, &c->cpus_allowed); |
| if (!nodes_empty(c->mems_allowed)) |
| guarantee_online_mems(c, &c->mems_allowed); |
| } |
| } |
| |
| /* |
| * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track |
| * cpu_online_map and node_states[N_HIGH_MEMORY]. Force the top cpuset to |
| * track what's online after any CPU or memory node hotplug or unplug |
| * event. |
| * |
| * To ensure that we don't remove a CPU or node from the top cpuset |
| * that is currently in use by a child cpuset (which would violate |
| * the rule that cpusets must be subsets of their parent), we first |
| * call the recursive routine guarantee_online_cpus_mems_in_subtree(). |
| * |
| * Since there are two callers of this routine, one for CPU hotplug |
| * events and one for memory node hotplug events, we could have coded |
| * two separate routines here. We code it as a single common routine |
| * in order to minimize text size. |
| */ |
| |
| static void common_cpu_mem_hotplug_unplug(void) |
| { |
| cgroup_lock(); |
| mutex_lock(&callback_mutex); |
| |
| guarantee_online_cpus_mems_in_subtree(&top_cpuset); |
| top_cpuset.cpus_allowed = cpu_online_map; |
| top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; |
| |
| mutex_unlock(&callback_mutex); |
| cgroup_unlock(); |
| } |
| |
| /* |
| * The top_cpuset tracks what CPUs and Memory Nodes are online, |
| * period. This is necessary in order to make cpusets transparent |
| * (of no affect) on systems that are actively using CPU hotplug |
| * but making no active use of cpusets. |
| * |
| * This routine ensures that top_cpuset.cpus_allowed tracks |
| * cpu_online_map on each CPU hotplug (cpuhp) event. |
| */ |
| |
| static int cpuset_handle_cpuhp(struct notifier_block *unused_nb, |
| unsigned long phase, void *unused_cpu) |
| { |
| if (phase == CPU_DYING || phase == CPU_DYING_FROZEN) |
| return NOTIFY_DONE; |
| |
| common_cpu_mem_hotplug_unplug(); |
| return 0; |
| } |
| |
| #ifdef CONFIG_MEMORY_HOTPLUG |
| /* |
| * Keep top_cpuset.mems_allowed tracking node_states[N_HIGH_MEMORY]. |
| * Call this routine anytime after you change |
| * node_states[N_HIGH_MEMORY]. |
| * See also the previous routine cpuset_handle_cpuhp(). |
| */ |
| |
| void cpuset_track_online_nodes(void) |
| { |
| common_cpu_mem_hotplug_unplug(); |
| } |
| #endif |
| |
| /** |
| * cpuset_init_smp - initialize cpus_allowed |
| * |
| * Description: Finish top cpuset after cpu, node maps are initialized |
| **/ |
| |
| void __init cpuset_init_smp(void) |
| { |
| top_cpuset.cpus_allowed = cpu_online_map; |
| top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; |
| |
| hotcpu_notifier(cpuset_handle_cpuhp, 0); |
| } |
| |
| /** |
| |
| * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. |
| * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. |
| * |
| * Description: Returns the cpumask_t cpus_allowed of the cpuset |
| * attached to the specified @tsk. Guaranteed to return some non-empty |
| * subset of cpu_online_map, even if this means going outside the |
| * tasks cpuset. |
| **/ |
| |
| cpumask_t cpuset_cpus_allowed(struct task_struct *tsk) |
| { |
| cpumask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| guarantee_online_cpus(task_cs(tsk), &mask); |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| |
| return mask; |
| } |
| |
| void cpuset_init_current_mems_allowed(void) |
| { |
| current->mems_allowed = NODE_MASK_ALL; |
| } |
| |
| /** |
| * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. |
| * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. |
| * |
| * Description: Returns the nodemask_t mems_allowed of the cpuset |
| * attached to the specified @tsk. Guaranteed to return some non-empty |
| * subset of node_states[N_HIGH_MEMORY], even if this means going outside the |
| * tasks cpuset. |
| **/ |
| |
| nodemask_t cpuset_mems_allowed(struct task_struct *tsk) |
| { |
| nodemask_t mask; |
| |
| mutex_lock(&callback_mutex); |
| task_lock(tsk); |
| guarantee_online_mems(task_cs(tsk), &mask); |
| task_unlock(tsk); |
| mutex_unlock(&callback_mutex); |
| |
| return mask; |
| } |
| |
| /** |
| * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed |
| * @zl: the zonelist to be checked |
| * |
| * Are any of the nodes on zonelist zl allowed in current->mems_allowed? |
| */ |
| int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl) |
| { |
| int i; |
| |
| for (i = 0; zl->zones[i]; i++) { |
| int nid = zone_to_nid(zl->zones[i]); |
| |
| if (node_isset(nid, current->mems_allowed)) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * nearest_exclusive_ancestor() - Returns the nearest mem_exclusive |
| * ancestor to the specified cpuset. Call holding callback_mutex. |
| * If no ancestor is mem_exclusive (an unusual configuration), then |
| * returns the root cpuset. |
| */ |
| static const struct cpuset *nearest_exclusive_ancestor(const struct cpuset *cs) |
| { |
| while (!is_mem_exclusive(cs) && cs->parent) |
| cs = cs->parent; |
| return cs; |
| } |
| |
| /** |
| * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node? |
| * @z: is this zone on an allowed node? |
| * @gfp_mask: memory allocation flags |
| * |
| * If we're in interrupt, yes, we can always allocate. If |
| * __GFP_THISNODE is set, yes, we can always allocate. If zone |
| * z's node is in our tasks mems_allowed, yes. If it's not a |
| * __GFP_HARDWALL request and this zone's nodes is in the nearest |
| * mem_exclusive cpuset ancestor to this tasks cpuset, yes. |
| * If the task has been OOM killed and has access to memory reserves |
| * as specified by the TIF_MEMDIE flag, yes. |
| * Otherwise, no. |
| * |
| * If __GFP_HARDWALL is set, cpuset_zone_allowed_softwall() |
| * reduces to cpuset_zone_allowed_hardwall(). Otherwise, |
| * cpuset_zone_allowed_softwall() might sleep, and might allow a zone |
| * from an enclosing cpuset. |
| * |
| * cpuset_zone_allowed_hardwall() only handles the simpler case of |
| * hardwall cpusets, and never sleeps. |
| * |
| * The __GFP_THISNODE placement logic is really handled elsewhere, |
| * by forcibly using a zonelist starting at a specified node, and by |
| * (in get_page_from_freelist()) refusing to consider the zones for |
| * any node on the zonelist except the first. By the time any such |
| * calls get to this routine, we should just shut up and say 'yes'. |
| * |
| * GFP_USER allocations are marked with the __GFP_HARDWALL bit, |
| * and do not allow allocations outside the current tasks cpuset |
| * unless the task has been OOM killed as is marked TIF_MEMDIE. |
| * GFP_KERNEL allocations are not so marked, so can escape to the |
| * nearest enclosing mem_exclusive ancestor cpuset. |
| * |
| * Scanning up parent cpusets requires callback_mutex. The |
| * __alloc_pages() routine only calls here with __GFP_HARDWALL bit |
| * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the |
| * current tasks mems_allowed came up empty on the first pass over |
| * the zonelist. So only GFP_KERNEL allocations, if all nodes in the |
| * cpuset are short of memory, might require taking the callback_mutex |
| * mutex. |
| * |
| * The first call here from mm/page_alloc:get_page_from_freelist() |
| * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, |
| * so no allocation on a node outside the cpuset is allowed (unless |
| * in interrupt, of course). |
| * |
| * The second pass through get_page_from_freelist() doesn't even call |
| * here for GFP_ATOMIC calls. For those calls, the __alloc_pages() |
| * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set |
| * in alloc_flags. That logic and the checks below have the combined |
| * affect that: |
| * in_interrupt - any node ok (current task context irrelevant) |
| * GFP_ATOMIC - any node ok |
| * TIF_MEMDIE - any node ok |
| * GFP_KERNEL - any node in enclosing mem_exclusive cpuset ok |
| * GFP_USER - only nodes in current tasks mems allowed ok. |
| * |
| * Rule: |
| * Don't call cpuset_zone_allowed_softwall if you can't sleep, unless you |
| * pass in the __GFP_HARDWALL flag set in gfp_flag, which disables |
| * the code that might scan up ancestor cpusets and sleep. |
| */ |
| |
| int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask) |
| { |
| int node; /* node that zone z is on */ |
| const struct cpuset *cs; /* current cpuset ancestors */ |
| int allowed; /* is allocation in zone z allowed? */ |
| |
| if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
| return 1; |
| node = zone_to_nid(z); |
| might_sleep_if(!(gfp_mask & __GFP_HARDWALL)); |
| if (node_isset(node, current->mems_allowed)) |
| return 1; |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return 1; |
| if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ |
| return 0; |
| |
| if (current->flags & PF_EXITING) /* Let dying task have memory */ |
| return 1; |
| |
| /* Not hardwall and node outside mems_allowed: scan up cpusets */ |
| mutex_lock(&callback_mutex); |
| |
| task_lock(current); |
| cs = nearest_exclusive_ancestor(task_cs(current)); |
| task_unlock(current); |
| |
| allowed = node_isset(node, cs->mems_allowed); |
| mutex_unlock(&callback_mutex); |
| return allowed; |
| } |
| |
| /* |
| * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node? |
| * @z: is this zone on an allowed node? |
| * @gfp_mask: memory allocation flags |
| * |
| * If we're in interrupt, yes, we can always allocate. |
| * If __GFP_THISNODE is set, yes, we can always allocate. If zone |
| * z's node is in our tasks mems_allowed, yes. If the task has been |
| * OOM killed and has access to memory reserves as specified by the |
| * TIF_MEMDIE flag, yes. Otherwise, no. |
| * |
| * The __GFP_THISNODE placement logic is really handled elsewhere, |
| * by forcibly using a zonelist starting at a specified node, and by |
| * (in get_page_from_freelist()) refusing to consider the zones for |
| * any node on the zonelist except the first. By the time any such |
| * calls get to this routine, we should just shut up and say 'yes'. |
| * |
| * Unlike the cpuset_zone_allowed_softwall() variant, above, |
| * this variant requires that the zone be in the current tasks |
| * mems_allowed or that we're in interrupt. It does not scan up the |
| * cpuset hierarchy for the nearest enclosing mem_exclusive cpuset. |
| * It never sleeps. |
| */ |
| |
| int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask) |
| { |
| int node; /* node that zone z is on */ |
| |
| if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) |
| return 1; |
| node = zone_to_nid(z); |
| if (node_isset(node, current->mems_allowed)) |
| return 1; |
| /* |
| * Allow tasks that have access to memory reserves because they have |
| * been OOM killed to get memory anywhere. |
| */ |
| if (unlikely(test_thread_flag(TIF_MEMDIE))) |
| return 1; |
| return 0; |
| } |
| |
| /** |
| * cpuset_lock - lock out any changes to cpuset structures |
| * |
| * The out of memory (oom) code needs to mutex_lock cpusets |
| * from being changed while it scans the tasklist looking for a |
| * task in an overlapping cpuset. Expose callback_mutex via this |
| * cpuset_lock() routine, so the oom code can lock it, before |
| * locking the task list. The tasklist_lock is a spinlock, so |
| * must be taken inside callback_mutex. |
| */ |
| |
| void cpuset_lock(void) |
| { |
| mutex_lock(&callback_mutex); |
| } |
| |
| /** |
| * cpuset_unlock - release lock on cpuset changes |
| * |
| * Undo the lock taken in a previous cpuset_lock() call. |
| */ |
| |
| void cpuset_unlock(void) |
| { |
| mutex_unlock(&callback_mutex); |
| } |
| |
| /** |
| * cpuset_mem_spread_node() - On which node to begin search for a page |
| * |
| * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for |
| * tasks in a cpuset with is_spread_page or is_spread_slab set), |
| * and if the memory allocation used cpuset_mem_spread_node() |
| * to determine on which node to start looking, as it will for |
| * certain page cache or slab cache pages such as used for file |
| * system buffers and inode caches, then instead of starting on the |
| * local node to look for a free page, rather spread the starting |
| * node around the tasks mems_allowed nodes. |
| * |
| * We don't have to worry about the returned node being offline |
| * because "it can't happen", and even if it did, it would be ok. |
| * |
| * The routines calling guarantee_online_mems() are careful to |
| * only set nodes in task->mems_allowed that are online. So it |
| * should not be possible for the following code to return an |
| * offline node. But if it did, that would be ok, as this routine |
| * is not returning the node where the allocation must be, only |
| * the node where the search should start. The zonelist passed to |
| * __alloc_pages() will include all nodes. If the slab allocator |
| * is passed an offline node, it will fall back to the local node. |
| * See kmem_cache_alloc_node(). |
| */ |
| |
| int cpuset_mem_spread_node(void) |
| { |
| int node; |
| |
| node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed); |
| if (node == MAX_NUMNODES) |
| node = first_node(current->mems_allowed); |
| current->cpuset_mem_spread_rotor = node; |
| return node; |
| } |
| EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); |
| |
| /** |
| * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? |
| * @tsk1: pointer to task_struct of some task. |
| * @tsk2: pointer to task_struct of some other task. |
| * |
| * Description: Return true if @tsk1's mems_allowed intersects the |
| * mems_allowed of @tsk2. Used by the OOM killer to determine if |
| * one of the task's memory usage might impact the memory available |
| * to the other. |
| **/ |
| |
| int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, |
| const struct task_struct *tsk2) |
| { |
| return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); |
| } |
| |
| /* |
| * Collection of memory_pressure is suppressed unless |
| * this flag is enabled by writing "1" to the special |
| * cpuset file 'memory_pressure_enabled' in the root cpuset. |
| */ |
| |
| int cpuset_memory_pressure_enabled __read_mostly; |
| |
| /** |
| * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. |
| * |
| * Keep a running average of the rate of synchronous (direct) |
| * page reclaim efforts initiated by tasks in each cpuset. |
| * |
| * This represents the rate at which some task in the cpuset |
| * ran low on memory on all nodes it was allowed to use, and |
| * had to enter the kernels page reclaim code in an effort to |
| * create more free memory by tossing clean pages or swapping |
| * or writing dirty pages. |
| * |
| * Display to user space in the per-cpuset read-only file |
| * "memory_pressure". Value displayed is an integer |
| * representing the recent rate of entry into the synchronous |
| * (direct) page reclaim by any task attached to the cpuset. |
| **/ |
| |
| void __cpuset_memory_pressure_bump(void) |
| { |
| task_lock(current); |
| fmeter_markevent(&task_cs(current)->fmeter); |
| task_unlock(current); |
| } |
| |
| #ifdef CONFIG_PROC_PID_CPUSET |
| /* |
| * proc_cpuset_show() |
| * - Print tasks cpuset path into seq_file. |
| * - Used for /proc/<pid>/cpuset. |
| * - No need to task_lock(tsk) on this tsk->cpuset reference, as it |
| * doesn't really matter if tsk->cpuset changes after we read it, |
| * and we take manage_mutex, keeping attach_task() from changing it |
| * anyway. No need to check that tsk->cpuset != NULL, thanks to |
| * the_top_cpuset_hack in cpuset_exit(), which sets an exiting tasks |
| * cpuset to top_cpuset. |
| */ |
| static int proc_cpuset_show(struct seq_file *m, void *unused_v) |
| { |
| struct pid *pid; |
| struct task_struct *tsk; |
| char *buf; |
| struct cgroup_subsys_state *css; |
| int retval; |
| |
| retval = -ENOMEM; |
| buf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
| if (!buf) |
| goto out; |
| |
| retval = -ESRCH; |
| pid = m->private; |
| tsk = get_pid_task(pid, PIDTYPE_PID); |
| if (!tsk) |
| goto out_free; |
| |
| retval = -EINVAL; |
| cgroup_lock(); |
| css = task_subsys_state(tsk, cpuset_subsys_id); |
| retval = cgroup_path(css->cgroup, buf, PAGE_SIZE); |
| if (retval < 0) |
| goto out_unlock; |
| seq_puts(m, buf); |
| seq_putc(m, '\n'); |
| out_unlock: |
| cgroup_unlock(); |
| put_task_struct(tsk); |
| out_free: |
| kfree(buf); |
| out: |
| return retval; |
| } |
| |
| static int cpuset_open(struct inode *inode, struct file *file) |
| { |
| struct pid *pid = PROC_I(inode)->pid; |
| return single_open(file, proc_cpuset_show, pid); |
| } |
| |
| const struct file_operations proc_cpuset_operations = { |
| .open = cpuset_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = single_release, |
| }; |
| #endif /* CONFIG_PROC_PID_CPUSET */ |
| |
| /* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */ |
| char *cpuset_task_status_allowed(struct task_struct *task, char *buffer) |
| { |
| buffer += sprintf(buffer, "Cpus_allowed:\t"); |
| buffer += cpumask_scnprintf(buffer, PAGE_SIZE, task->cpus_allowed); |
| buffer += sprintf(buffer, "\n"); |
| buffer += sprintf(buffer, "Mems_allowed:\t"); |
| buffer += nodemask_scnprintf(buffer, PAGE_SIZE, task->mems_allowed); |
| buffer += sprintf(buffer, "\n"); |
| return buffer; |
| } |