diff options
Diffstat (limited to 'kernel/cpuset.c')
| -rw-r--r-- | kernel/cpuset.c | 2753 |
1 files changed, 0 insertions, 2753 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c deleted file mode 100644 index e5657788fedd..000000000000 --- a/kernel/cpuset.c +++ /dev/null @@ -1,2753 +0,0 @@ -/* - * 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 - * 2008 Rework of the scheduler domains and CPU hotplug handling - * by Max Krasnyansky - * - * 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/memory.h> -#include <linux/export.h> -#include <linux/mount.h> -#include <linux/namei.h> -#include <linux/pagemap.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 <linux/atomic.h> -#include <linux/mutex.h> -#include <linux/workqueue.h> -#include <linux/cgroup.h> -#include <linux/wait.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; - -/* Forward declare cgroup structures */ -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_var_t cpus_allowed; /* CPUs allowed to tasks in cpuset */ - nodemask_t mems_allowed; /* Memory Nodes allowed to tasks */ - - /* - * This is old Memory Nodes tasks took on. - * - * - top_cpuset.old_mems_allowed is initialized to mems_allowed. - * - A new cpuset's old_mems_allowed is initialized when some - * task is moved into it. - * - old_mems_allowed is used in cpuset_migrate_mm() when we change - * cpuset.mems_allowed and have tasks' nodemask updated, and - * then old_mems_allowed is updated to mems_allowed. - */ - nodemask_t old_mems_allowed; - - struct fmeter fmeter; /* memory_pressure filter */ - - /* - * Tasks are being attached to this cpuset. Used to prevent - * zeroing cpus/mems_allowed between ->can_attach() and ->attach(). - */ - int attach_in_progress; - - /* partition number for rebuild_sched_domains() */ - int pn; - - /* for custom sched domain */ - int relax_domain_level; -}; - -/* Retrieve the cpuset for a cgroup */ -static inline struct cpuset *cgroup_cs(struct cgroup *cgrp) -{ - return container_of(cgroup_subsys_state(cgrp, 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); -} - -static inline struct cpuset *parent_cs(const struct cpuset *cs) -{ - struct cgroup *pcgrp = cs->css.cgroup->parent; - - if (pcgrp) - return cgroup_cs(pcgrp); - return NULL; -} - -#ifdef CONFIG_NUMA -static inline bool task_has_mempolicy(struct task_struct *task) -{ - return task->mempolicy; -} -#else -static inline bool task_has_mempolicy(struct task_struct *task) -{ - return false; -} -#endif - - -/* bits in struct cpuset flags field */ -typedef enum { - CS_ONLINE, - CS_CPU_EXCLUSIVE, - CS_MEM_EXCLUSIVE, - CS_MEM_HARDWALL, - CS_MEMORY_MIGRATE, - CS_SCHED_LOAD_BALANCE, - CS_SPREAD_PAGE, - CS_SPREAD_SLAB, -} cpuset_flagbits_t; - -/* convenient tests for these bits */ -static inline bool is_cpuset_online(const struct cpuset *cs) -{ - return test_bit(CS_ONLINE, &cs->flags); -} - -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_mem_hardwall(const struct cpuset *cs) -{ - return test_bit(CS_MEM_HARDWALL, &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); -} - -static struct cpuset top_cpuset = { - .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | - (1 << CS_MEM_EXCLUSIVE)), -}; - -/** - * cpuset_for_each_child - traverse online children of a cpuset - * @child_cs: loop cursor pointing to the current child - * @pos_cgrp: used for iteration - * @parent_cs: target cpuset to walk children of - * - * Walk @child_cs through the online children of @parent_cs. Must be used - * with RCU read locked. - */ -#define cpuset_for_each_child(child_cs, pos_cgrp, parent_cs) \ - cgroup_for_each_child((pos_cgrp), (parent_cs)->css.cgroup) \ - if (is_cpuset_online(((child_cs) = cgroup_cs((pos_cgrp))))) - -/** - * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants - * @des_cs: loop cursor pointing to the current descendant - * @pos_cgrp: used for iteration - * @root_cs: target cpuset to walk ancestor of - * - * Walk @des_cs through the online descendants of @root_cs. Must be used - * with RCU read locked. The caller may modify @pos_cgrp by calling - * cgroup_rightmost_descendant() to skip subtree. - */ -#define cpuset_for_each_descendant_pre(des_cs, pos_cgrp, root_cs) \ - cgroup_for_each_descendant_pre((pos_cgrp), (root_cs)->css.cgroup) \ - if (is_cpuset_online(((des_cs) = cgroup_cs((pos_cgrp))))) - -/* - * There are two global mutexes guarding cpuset structures - cpuset_mutex - * and callback_mutex. The latter may nest inside the former. We also - * require taking task_lock() when dereferencing a task's 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 - * cpuset_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 cpuset_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. - * - * Now, the task_struct fields mems_allowed and mempolicy may be changed - * by other task, we use alloc_lock in the task_struct fields to protect - * them. - * - * 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. - * - * Accessing a task's cpuset should be done in accordance with the - * guidelines for accessing subsystem state in kernel/cgroup.c - */ - -static DEFINE_MUTEX(cpuset_mutex); -static DEFINE_MUTEX(callback_mutex); - -/* - * CPU / memory hotplug is handled asynchronously. - */ -static void cpuset_hotplug_workfn(struct work_struct *work); -static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn); - -static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq); - -/* - * 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 struct dentry *cpuset_mount(struct file_system_type *fs_type, - int flags, const char *unused_dev_name, void *data) -{ - struct file_system_type *cgroup_fs = get_fs_type("cgroup"); - struct dentry *ret = ERR_PTR(-ENODEV); - if (cgroup_fs) { - char mountopts[] = - "cpuset,noprefix," - "release_agent=/sbin/cpuset_release_agent"; - ret = cgroup_fs->mount(cgroup_fs, flags, - unused_dev_name, mountopts); - put_filesystem(cgroup_fs); - } - return ret; -} - -static struct file_system_type cpuset_fs_type = { - .name = "cpuset", - .mount = cpuset_mount, -}; - -/* - * 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. The top - * cpuset always has some cpus online. - * - * One way or another, we guarantee to return some non-empty subset - * of cpu_online_mask. - * - * Call with callback_mutex held. - */ -static void guarantee_online_cpus(const struct cpuset *cs, - struct cpumask *pmask) -{ - while (!cpumask_intersects(cs->cpus_allowed, cpu_online_mask)) - cs = parent_cs(cs); - cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask); -} - -/* - * 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. The top cpuset always has some mems online. - * - * One way or another, we guarantee to return some non-empty subset - * of node_states[N_MEMORY]. - * - * Call with callback_mutex held. - */ -static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask) -{ - while (!nodes_intersects(cs->mems_allowed, node_states[N_MEMORY])) - cs = parent_cs(cs); - nodes_and(*pmask, cs->mems_allowed, node_states[N_MEMORY]); -} - -/* - * update task's spread flag if cpuset's page/slab spread flag is set - * - * Called with callback_mutex/cpuset_mutex held - */ -static void cpuset_update_task_spread_flag(struct cpuset *cs, - struct task_struct *tsk) -{ - 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; -} - -/* - * 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 cpuset_mutex. - */ - -static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) -{ - return cpumask_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); -} - -/** - * alloc_trial_cpuset - allocate a trial cpuset - * @cs: the cpuset that the trial cpuset duplicates - */ -static struct cpuset *alloc_trial_cpuset(const struct cpuset *cs) -{ - struct cpuset *trial; - - trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL); - if (!trial) - return NULL; - - if (!alloc_cpumask_var(&trial->cpus_allowed, GFP_KERNEL)) { - kfree(trial); - return NULL; - } - cpumask_copy(trial->cpus_allowed, cs->cpus_allowed); - - return trial; -} - -/** - * free_trial_cpuset - free the trial cpuset - * @trial: the trial cpuset to be freed - */ -static void free_trial_cpuset(struct cpuset *trial) -{ - free_cpumask_var(trial->cpus_allowed); - kfree(trial); -} - -/* - * 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 - * cpuset_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 *cgrp; - struct cpuset *c, *par; - int ret; - - rcu_read_lock(); - - /* Each of our child cpusets must be a subset of us */ - ret = -EBUSY; - cpuset_for_each_child(c, cgrp, cur) - if (!is_cpuset_subset(c, trial)) - goto out; - - /* Remaining checks don't apply to root cpuset */ - ret = 0; - if (cur == &top_cpuset) - goto out; - - par = parent_cs(cur); - - /* We must be a subset of our parent cpuset */ - ret = -EACCES; - if (!is_cpuset_subset(trial, par)) - goto out; - - /* - * If either I or some sibling (!= me) is exclusive, we can't - * overlap - */ - ret = -EINVAL; - cpuset_for_each_child(c, cgrp, par) { - if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && - c != cur && - cpumask_intersects(trial->cpus_allowed, c->cpus_allowed)) - goto out; - if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && - c != cur && - nodes_intersects(trial->mems_allowed, c->mems_allowed)) - goto out; - } - - /* - * Cpusets with tasks - existing or newly being attached - can't - * have empty cpus_allowed or mems_allowed. - */ - ret = -ENOSPC; - if ((cgroup_task_count(cur->css.cgroup) || cur->attach_in_progress) && - (cpumask_empty(trial->cpus_allowed) && - nodes_empty(trial->mems_allowed))) - goto out; - - ret = 0; -out: - rcu_read_unlock(); - return ret; -} - -#ifdef CONFIG_SMP -/* - * Helper routine for generate_sched_domains(). - * Do cpusets a, b have overlapping cpus_allowed masks? - */ -static int cpusets_overlap(struct cpuset *a, struct cpuset *b) -{ - return cpumask_intersects(a->cpus_allowed, b->cpus_allowed); -} - -static void -update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) -{ - if (dattr->relax_domain_level < c->relax_domain_level) - dattr->relax_domain_level = c->relax_domain_level; - return; -} - -static void update_domain_attr_tree(struct sched_domain_attr *dattr, - struct cpuset *root_cs) -{ - struct cpuset *cp; - struct cgroup *pos_cgrp; - - rcu_read_lock(); - cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) { - /* skip the whole subtree if @cp doesn't have any CPU */ - if (cpumask_empty(cp->cpus_allowed)) { - pos_cgrp = cgroup_rightmost_descendant(pos_cgrp); - continue; - } - - if (is_sched_load_balance(cp)) - update_domain_attr(dattr, cp); - } - rcu_read_unlock(); -} - -/* - * generate_sched_domains() - * - * This function builds a partial partition of the systems CPUs - * A 'partial partition' is a set of non-overlapping subsets whose - * union is a subset of that set. - * The output of this function needs to be passed to kernel/sched/core.c - * partition_sched_domains() routine, which will rebuild the scheduler's - * load balancing domains (sched domains) as specified by that partial - * partition. - * - * See "What is sched_load_balance" in Documentation/cgroups/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. - * - * Must be called with cpuset_mutex held. - * - * The three key local variables below are: - * q - a linked-list 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/core.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 int generate_sched_domains(cpumask_var_t **domains, - struct sched_domain_attr **attributes) -{ - 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_var_t *doms; /* resulting partition; i.e. sched domains */ - struct sched_domain_attr *dattr; /* attributes for custom domains */ - int ndoms = 0; /* number of sched domains in result */ - int nslot; /* next empty doms[] struct cpumask slot */ - struct cgroup *pos_cgrp; - - doms = NULL; - dattr = NULL; - csa = NULL; - - /* Special case for the 99% of systems with one, full, sched domain */ - if (is_sched_load_balance(&top_cpuset)) { - ndoms = 1; - doms = alloc_sched_domains(ndoms); - if (!doms) - goto done; - - dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); - if (dattr) { - *dattr = SD_ATTR_INIT; - update_domain_attr_tree(dattr, &top_cpuset); - } - cpumask_copy(doms[0], top_cpuset.cpus_allowed); - - goto done; - } - - csa = kmalloc(number_of_cpusets * sizeof(cp), GFP_KERNEL); - if (!csa) - goto done; - csn = 0; - - rcu_read_lock(); - cpuset_for_each_descendant_pre(cp, pos_cgrp, &top_cpuset) { - /* - * Continue traversing beyond @cp iff @cp has some CPUs and - * isn't load balancing. The former is obvious. The - * latter: All child cpusets contain a subset of the - * parent's cpus, so just skip them, and then we call - * update_domain_attr_tree() to calc relax_domain_level of - * the corresponding sched domain. - */ - if (!cpumask_empty(cp->cpus_allowed) && - !is_sched_load_balance(cp)) - continue; - - if (is_sched_load_balance(cp)) - csa[csn++] = cp; - - /* skip @cp's subtree */ - pos_cgrp = cgroup_rightmost_descendant(pos_cgrp); - } - rcu_read_unlock(); - - 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; - } - } - } - - /* - * Now we know how many domains to create. - * Convert <csn, csa> to <ndoms, doms> and populate cpu masks. - */ - doms = alloc_sched_domains(ndoms); - if (!doms) - goto done; - - /* - * The rest of the code, including the scheduler, can deal with - * dattr==NULL case. No need to abort if alloc fails. - */ - dattr = kmalloc(ndoms * sizeof(struct sched_domain_attr), GFP_KERNEL); - - for (nslot = 0, i = 0; i < csn; i++) { - struct cpuset *a = csa[i]; - struct cpumask *dp; - int apn = a->pn; - - if (apn < 0) { - /* Skip completed partitions */ - continue; - } - - 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; - } - - cpumask_clear(dp); - if (dattr) - *(dattr + nslot) = SD_ATTR_INIT; - for (j = i; j < csn; j++) { - struct cpuset *b = csa[j]; - - if (apn == b->pn) { - cpumask_or(dp, dp, b->cpus_allowed); - if (dattr) - update_domain_attr_tree(dattr + nslot, b); - - /* Done with this partition */ - b->pn = -1; - } - } - nslot++; - } - BUG_ON(nslot != ndoms); - -done: - kfree(csa); - - /* - * Fallback to the default domain if kmalloc() failed. - * See comments in partition_sched_domains(). - */ - if (doms == NULL) - ndoms = 1; - - *domains = doms; - *attributes = dattr; - return ndoms; -} - -/* - * Rebuild scheduler 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. - * - * Call with cpuset_mutex held. Takes get_online_cpus(). - */ -static void rebuild_sched_domains_locked(void) -{ - struct sched_domain_attr *attr; - cpumask_var_t *doms; - int ndoms; - - lockdep_assert_held(&cpuset_mutex); - get_online_cpus(); - - /* - * We have raced with CPU hotplug. Don't do anything to avoid - * passing doms with offlined cpu to partition_sched_domains(). - * Anyways, hotplug work item will rebuild sched domains. - */ - if (!cpumask_equal(top_cpuset.cpus_allowed, cpu_active_mask)) - goto out; - - /* Generate domain masks and attrs */ - ndoms = generate_sched_domains(&doms, &attr); - - /* Have scheduler rebuild the domains */ - partition_sched_domains(ndoms, doms, attr); -out: - put_online_cpus(); -} -#else /* !CONFIG_SMP */ -static void rebuild_sched_domains_locked(void) -{ -} -#endif /* CONFIG_SMP */ - -void rebuild_sched_domains(void) -{ - mutex_lock(&cpuset_mutex); - rebuild_sched_domains_locked(); - mutex_unlock(&cpuset_mutex); -} - -/* - * effective_cpumask_cpuset - return nearest ancestor with non-empty cpus - * @cs: the cpuset in interest - * - * A cpuset's effective cpumask is the cpumask of the nearest ancestor - * with non-empty cpus. We use effective cpumask whenever: - * - we update tasks' cpus_allowed. (they take on the ancestor's cpumask - * if the cpuset they reside in has no cpus) - * - we want to retrieve task_cs(tsk)'s cpus_allowed. - * - * Called with cpuset_mutex held. cpuset_cpus_allowed_fallback() is an - * exception. See comments there. - */ -static struct cpuset *effective_cpumask_cpuset(struct cpuset *cs) -{ - while (cpumask_empty(cs->cpus_allowed)) - cs = parent_cs(cs); - return cs; -} - -/* - * effective_nodemask_cpuset - return nearest ancestor with non-empty mems - * @cs: the cpuset in interest - * - * A cpuset's effective nodemask is the nodemask of the nearest ancestor - * with non-empty memss. We use effective nodemask whenever: - * - we update tasks' mems_allowed. (they take on the ancestor's nodemask - * if the cpuset they reside in has no mems) - * - we want to retrieve task_cs(tsk)'s mems_allowed. - * - * Called with cpuset_mutex held. - */ -static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs) -{ - while (nodes_empty(cs->mems_allowed)) - cs = parent_cs(cs); - return cs; -} - -/** - * cpuset_change_cpumask - make a task's cpus_allowed the same as its cpuset's - * @tsk: task to test - * @scan: struct cgroup_scanner containing the cgroup of the task - * - * Called by cgroup_scan_tasks() for each task in a cgroup whose - * cpus_allowed mask needs to be changed. - * - * We don't need to re-check for the cgroup/cpuset membership, since we're - * holding cpuset_mutex at this point. - */ -static void cpuset_change_cpumask(struct task_struct *tsk, - struct cgroup_scanner *scan) -{ - struct cpuset *cpus_cs; - - cpus_cs = effective_cpumask_cpuset(cgroup_cs(scan->cg)); - set_cpus_allowed_ptr(tsk, cpus_cs->cpus_allowed); -} - -/** - * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. - * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed - * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks() - * - * Called with cpuset_mutex held - * - * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, - * calling callback functions for each. - * - * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0 - * if @heap != NULL. - */ -static void update_tasks_cpumask(struct cpuset *cs, struct ptr_heap *heap) -{ - struct cgroup_scanner scan; - - scan.cg = cs->css.cgroup; - scan.test_task = NULL; - scan.process_task = cpuset_change_cpumask; - scan.heap = heap; - cgroup_scan_tasks(&scan); -} - -/* - * update_tasks_cpumask_hier - Update the cpumasks of tasks in the hierarchy. - * @root_cs: the root cpuset of the hierarchy - * @update_root: update root cpuset or not? - * @heap: the heap used by cgroup_scan_tasks() - * - * This will update cpumasks of tasks in @root_cs and all other empty cpusets - * which take on cpumask of @root_cs. - * - * Called with cpuset_mutex held - */ -static void update_tasks_cpumask_hier(struct cpuset *root_cs, - bool update_root, struct ptr_heap *heap) -{ - struct cpuset *cp; - struct cgroup *pos_cgrp; - - if (update_root) - update_tasks_cpumask(root_cs, heap); - - rcu_read_lock(); - cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) { - /* skip the whole subtree if @cp have some CPU */ - if (!cpumask_empty(cp->cpus_allowed)) { - pos_cgrp = cgroup_rightmost_descendant(pos_cgrp); - continue; - } - if (!css_tryget(&cp->css)) - continue; - rcu_read_unlock(); - - update_tasks_cpumask(cp, heap); - - rcu_read_lock(); - css_put(&cp->css); - } - rcu_read_unlock(); -} - -/** - * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it - * @cs: the cpuset to consider - * @buf: buffer of cpu numbers written to this cpuset - */ -static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, - const char *buf) -{ - struct ptr_heap heap; - int retval; - int is_load_balanced; - - /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */ - if (cs == &top_cpuset) - return -EACCES; - - /* - * An empty cpus_allowed is ok only if the cpuset has no tasks. - * Since cpulist_parse() fails on an empty mask, we special case - * that parsing. The validate_change() call ensures that cpusets - * with tasks have cpus. - */ - if (!*buf) { - cpumask_clear(trialcs->cpus_allowed); - } else { - retval = cpulist_parse(buf, trialcs->cpus_allowed); - if (retval < 0) - return retval; - - if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask)) - return -EINVAL; - } - - /* Nothing to do if the cpus didn't change */ - if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) - return 0; - - retval = validate_change(cs, trialcs); - if (retval < 0) - return retval; - - retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); - if (retval) - return retval; - - is_load_balanced = is_sched_load_balance(trialcs); - - mutex_lock(&callback_mutex); - cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); - mutex_unlock(&callback_mutex); - - update_tasks_cpumask_hier(cs, true, &heap); - - heap_free(&heap); - - if (is_load_balanced) - rebuild_sched_domains_locked(); - 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 cpuset_mutex, so current's cpuset won't change - * during this call, as manage_mutex holds off any cpuset_attach() - * 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 task's cpuset. - * - * 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. - */ - -static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, - const nodemask_t *to) -{ - struct task_struct *tsk = current; - struct cpuset *mems_cs; - - tsk->mems_allowed = *to; - - do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL); - - mems_cs = effective_nodemask_cpuset(task_cs(tsk)); - guarantee_online_mems(mems_cs, &tsk->mems_allowed); -} - -/* - * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy - * @tsk: the task to change - * @newmems: new nodes that the task will be set - * - * In order to avoid seeing no nodes if the old and new nodes are disjoint, - * we structure updates as setting all new allowed nodes, then clearing newly - * disallowed ones. - */ -static void cpuset_change_task_nodemask(struct task_struct *tsk, - nodemask_t *newmems) -{ - bool need_loop; - - /* - * 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; - if (current->flags & PF_EXITING) /* Let dying task have memory */ - return; - - task_lock(tsk); - /* - * Determine if a loop is necessary if another thread is doing - * get_mems_allowed(). If at least one node remains unchanged and - * tsk does not have a mempolicy, then an empty nodemask will not be - * possible when mems_allowed is larger than a word. - */ - need_loop = task_has_mempolicy(tsk) || - !nodes_intersects(*newmems, tsk->mems_allowed); - - if (need_loop) - write_seqcount_begin(&tsk->mems_allowed_seq); - - nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); - mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1); - - mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2); - tsk->mems_allowed = *newmems; - - if (need_loop) - write_seqcount_end(&tsk->mems_allowed_seq); - - task_unlock(tsk); -} - -/* - * Update task's mems_allowed and rebind its mempolicy and vmas' mempolicy - * of it to cpuset's new mems_allowed, and migrate pages to new nodes if - * memory_migrate flag is set. Called with cpuset_mutex held. - */ -static void cpuset_change_nodemask(struct task_struct *p, - struct cgroup_scanner *scan) -{ - struct cpuset *cs = cgroup_cs(scan->cg); - struct mm_struct *mm; - int migrate; - nodemask_t *newmems = scan->data; - - cpuset_change_task_nodemask(p, newmems); - - mm = get_task_mm(p); - if (!mm) - return; - - migrate = is_memory_migrate(cs); - - mpol_rebind_mm(mm, &cs->mems_allowed); - if (migrate) - cpuset_migrate_mm(mm, &cs->old_mems_allowed, newmems); - mmput(mm); -} - -static void *cpuset_being_rebound; - -/** - * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset. - * @cs: the cpuset in which each task's mems_allowed mask needs to be changed - * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks() - * - * Called with cpuset_mutex held - * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0 - * if @heap != NULL. - */ -static void update_tasks_nodemask(struct cpuset *cs, struct ptr_heap *heap) -{ - static nodemask_t newmems; /* protected by cpuset_mutex */ - struct cgroup_scanner scan; - struct cpuset *mems_cs = effective_nodemask_cpuset(cs); - - cpuset_being_rebound = cs; /* causes mpol_dup() rebind */ - - guarantee_online_mems(mems_cs, &newmems); - - scan.cg = cs->css.cgroup; - scan.test_task = NULL; - scan.process_task = cpuset_change_nodemask; - scan.heap = heap; - scan.data = &newmems; - - /* - * The mpol_rebind_mm() call takes mmap_sem, which we couldn't - * take while holding tasklist_lock. Forks can happen - the - * mpol_dup() cpuset_being_rebound check will catch such forks, - * and rebind their vma mempolicies too. Because we still hold - * the global cpuset_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. - */ - cgroup_scan_tasks(&scan); - - /* - * All the tasks' nodemasks have been updated, update - * cs->old_mems_allowed. - */ - cs->old_mems_allowed = newmems; - - /* We're done rebinding vmas to this cpuset's new mems_allowed. */ - cpuset_being_rebound = NULL; -} - -/* - * update_tasks_nodemask_hier - Update the nodemasks of tasks in the hierarchy. - * @cs: the root cpuset of the hierarchy - * @update_root: update the root cpuset or not? - * @heap: the heap used by cgroup_scan_tasks() - * - * This will update nodemasks of tasks in @root_cs and all other empty cpusets - * which take on nodemask of @root_cs. - * - * Called with cpuset_mutex held - */ -static void update_tasks_nodemask_hier(struct cpuset *root_cs, - bool update_root, struct ptr_heap *heap) -{ - struct cpuset *cp; - struct cgroup *pos_cgrp; - - if (update_root) - update_tasks_nodemask(root_cs, heap); - - rcu_read_lock(); - cpuset_for_each_descendant_pre(cp, pos_cgrp, root_cs) { - /* skip the whole subtree if @cp have some CPU */ - if (!nodes_empty(cp->mems_allowed)) { - pos_cgrp = cgroup_rightmost_descendant(pos_cgrp); - continue; - } - if (!css_tryget(&cp->css)) - continue; - rcu_read_unlock(); - - update_tasks_nodemask(cp, heap); - - rcu_read_lock(); - css_put(&cp->css); - } - rcu_read_unlock(); -} - -/* - * Handle user request to change the 'mems' memory placement - * of a cpuset. Needs to validate the request, update the - * cpusets mems_allowed, and for each task in the cpuset, - * update mems_allowed and rebind task's mempolicy and any vma - * mempolicies and if the cpuset is marked 'memory_migrate', - * migrate the tasks pages to the new memory. - * - * Call with cpuset_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 int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, - const char *buf) -{ - int retval; - struct ptr_heap heap; - - /* - * top_cpuset.mems_allowed tracks node_stats[N_MEMORY]; - * it's read-only - */ - if (cs == &top_cpuset) { - retval = -EACCES; - goto done; - } - - /* - * 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. - */ - if (!*buf) { - nodes_clear(trialcs->mems_allowed); - } else { - retval = nodelist_parse(buf, trialcs->mems_allowed); - if (retval < 0) - goto done; - - if (!nodes_subset(trialcs->mems_allowed, - node_states[N_MEMORY])) { - retval = -EINVAL; - goto done; - } - } - - if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) { - retval = 0; /* Too easy - nothing to do */ - goto done; - } - retval = validate_change(cs, trialcs); - if (retval < 0) - goto done; - - retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); - if (retval < 0) - goto done; - - mutex_lock(&callback_mutex); - cs->mems_allowed = trialcs->mems_allowed; - mutex_unlock(&callback_mutex); - - update_tasks_nodemask_hier(cs, true, &heap); - - heap_free(&heap); -done: - return retval; -} - -int current_cpuset_is_being_rebound(void) -{ - return task_cs(current) == cpuset_being_rebound; -} - -static int update_relax_domain_level(struct cpuset *cs, s64 val) -{ -#ifdef CONFIG_SMP - if (val < -1 || val >= sched_domain_level_max) - return -EINVAL; -#endif - - if (val != cs->relax_domain_level) { - cs->relax_domain_level = val; - if (!cpumask_empty(cs->cpus_allowed) && - is_sched_load_balance(cs)) - rebuild_sched_domains_locked(); - } - - return 0; -} - -/* - * cpuset_change_flag - make a task's spread flags the same as its cpuset's - * @tsk: task to be updated - * @scan: struct cgroup_scanner containing the cgroup of the task - * - * Called by cgroup_scan_tasks() for each task in a cgroup. - * - * We don't need to re-check for the cgroup/cpuset membership, since we're - * holding cpuset_mutex at this point. - */ -static void cpuset_change_flag(struct task_struct *tsk, - struct cgroup_scanner *scan) -{ - cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk); -} - -/* - * update_tasks_flags - update the spread flags of tasks in the cpuset. - * @cs: the cpuset in which each task's spread flags needs to be changed - * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks() - * - * Called with cpuset_mutex held - * - * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, - * calling callback functions for each. - * - * No return value. It's guaranteed that cgroup_scan_tasks() always returns 0 - * if @heap != NULL. - */ -static void update_tasks_flags(struct cpuset *cs, struct ptr_heap *heap) -{ - struct cgroup_scanner scan; - - scan.cg = cs->css.cgroup; - scan.test_task = NULL; - scan.process_task = cpuset_change_flag; - scan.heap = heap; - cgroup_scan_tasks(&scan); -} - -/* - * update_flag - read a 0 or a 1 in a file and update associated flag - * bit: the bit to update (see cpuset_flagbits_t) - * cs: the cpuset to update - * turning_on: whether the flag is being set or cleared - * - * Call with cpuset_mutex held. - */ - -static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, - int turning_on) -{ - struct cpuset *trialcs; - int balance_flag_changed; - int spread_flag_changed; - struct ptr_heap heap; - int err; - - trialcs = alloc_trial_cpuset(cs); - if (!trialcs) - return -ENOMEM; - - if (turning_on) - set_bit(bit, &trialcs->flags); - else - clear_bit(bit, &trialcs->flags); - - err = validate_change(cs, trialcs); - if (err < 0) - goto out; - - err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); - if (err < 0) - goto out; - - balance_flag_changed = (is_sched_load_balance(cs) != - is_sched_load_balance(trialcs)); - - spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) - || (is_spread_page(cs) != is_spread_page(trialcs))); - - mutex_lock(&callback_mutex); - cs->flags = trialcs->flags; - mutex_unlock(&callback_mutex); - - if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) - rebuild_sched_domains_locked(); - - if (spread_flag_changed) - update_tasks_flags(cs, &heap); - heap_free(&heap); -out: - free_trial_cpuset(trialcs); - return err; -} - -/* - * 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; -} - -/* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */ -static int cpuset_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) -{ - struct cpuset *cs = cgroup_cs(cgrp); - struct task_struct *task; - int ret; - - mutex_lock(&cpuset_mutex); - - /* - * We allow to move tasks into an empty cpuset if sane_behavior - * flag is set. - */ - ret = -ENOSPC; - if (!cgroup_sane_behavior(cgrp) && - (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))) - goto out_unlock; - - cgroup_taskset_for_each(task, cgrp, tset) { - /* - * Kthreads which disallow setaffinity shouldn't be moved - * to a new cpuset; we don't want to change their cpu - * affinity and isolating such threads by their set of - * allowed nodes is unnecessary. Thus, cpusets are not - * applicable for such threads. This prevents checking for - * success of set_cpus_allowed_ptr() on all attached tasks - * before cpus_allowed may be changed. - */ - ret = -EINVAL; - if (task->flags & PF_NO_SETAFFINITY) - goto out_unlock; - ret = security_task_setscheduler(task); - if (ret) - goto out_unlock; - } - - /* - * Mark attach is in progress. This makes validate_change() fail - * changes which zero cpus/mems_allowed. - */ - cs->attach_in_progress++; - ret = 0; -out_unlock: - mutex_unlock(&cpuset_mutex); - return ret; -} - -static void cpuset_cancel_attach(struct cgroup *cgrp, - struct cgroup_taskset *tset) -{ - mutex_lock(&cpuset_mutex); - cgroup_cs(cgrp)->attach_in_progress--; - mutex_unlock(&cpuset_mutex); -} - -/* - * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach() - * but we can't allocate it dynamically there. Define it global and - * allocate from cpuset_init(). - */ -static cpumask_var_t cpus_attach; - -static void cpuset_attach(struct cgroup *cgrp, struct cgroup_taskset *tset) -{ - /* static buf protected by cpuset_mutex */ - static nodemask_t cpuset_attach_nodemask_to; - struct mm_struct *mm; - struct task_struct *task; - struct task_struct *leader = cgroup_taskset_first(tset); - struct cgroup *oldcgrp = cgroup_taskset_cur_cgroup(tset); - struct cpuset *cs = cgroup_cs(cgrp); - struct cpuset *oldcs = cgroup_cs(oldcgrp); - struct cpuset *cpus_cs = effective_cpumask_cpuset(cs); - struct cpuset *mems_cs = effective_nodemask_cpuset(cs); - - mutex_lock(&cpuset_mutex); - - /* prepare for attach */ - if (cs == &top_cpuset) - cpumask_copy(cpus_attach, cpu_possible_mask); - else - guarantee_online_cpus(cpus_cs, cpus_attach); - - guarantee_online_mems(mems_cs, &cpuset_attach_nodemask_to); - - cgroup_taskset_for_each(task, cgrp, tset) { - /* - * can_attach beforehand should guarantee that this doesn't - * fail. TODO: have a better way to handle failure here - */ - WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); - - cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); - cpuset_update_task_spread_flag(cs, task); - } - - /* - * Change mm, possibly for multiple threads in a threadgroup. This is - * expensive and may sleep. - */ - cpuset_attach_nodemask_to = cs->mems_allowed; - mm = get_task_mm(leader); - if (mm) { - struct cpuset *mems_oldcs = effective_nodemask_cpuset(oldcs); - - mpol_rebind_mm(mm, &cpuset_attach_nodemask_to); - - /* - * old_mems_allowed is the same with mems_allowed here, except - * if this task is being moved automatically due to hotplug. - * In that case @mems_allowed has been updated and is empty, - * so @old_mems_allowed is the right nodesets that we migrate - * mm from. - */ - if (is_memory_migrate(cs)) { - cpuset_migrate_mm(mm, &mems_oldcs->old_mems_allowed, - &cpuset_attach_nodemask_to); - } - mmput(mm); - } - - cs->old_mems_allowed = cpuset_attach_nodemask_to; - - cs->attach_in_progress--; - if (!cs->attach_in_progress) - wake_up(&cpuset_attach_wq); - - mutex_unlock(&cpuset_mutex); -} - -/* 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_MEM_HARDWALL, - FILE_SCHED_LOAD_BALANCE, - FILE_SCHED_RELAX_DOMAIN_LEVEL, - FILE_MEMORY_PRESSURE_ENABLED, - FILE_MEMORY_PRESSURE, - FILE_SPREAD_PAGE, - FILE_SPREAD_SLAB, -} cpuset_filetype_t; - -static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val) -{ - struct cpuset *cs = cgroup_cs(cgrp); - cpuset_filetype_t type = cft->private; - int retval = -ENODEV; - - mutex_lock(&cpuset_mutex); - if (!is_cpuset_online(cs)) - goto out_unlock; - - switch (type) { - case FILE_CPU_EXCLUSIVE: - retval = update_flag(CS_CPU_EXCLUSIVE, cs, val); - break; - case FILE_MEM_EXCLUSIVE: - retval = update_flag(CS_MEM_EXCLUSIVE, cs, val); - break; - case FILE_MEM_HARDWALL: - retval = update_flag(CS_MEM_HARDWALL, cs, val); - break; - case FILE_SCHED_LOAD_BALANCE: - retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val); - break; - case FILE_MEMORY_MIGRATE: - retval = update_flag(CS_MEMORY_MIGRATE, cs, val); - break; - case FILE_MEMORY_PRESSURE_ENABLED: - cpuset_memory_pressure_enabled = !!val; - break; - case FILE_MEMORY_PRESSURE: - retval = -EACCES; - break; - case FILE_SPREAD_PAGE: - retval = update_flag(CS_SPREAD_PAGE, cs, val); - break; - case FILE_SPREAD_SLAB: - retval = update_flag(CS_SPREAD_SLAB, cs, val); - break; - default: - retval = -EINVAL; - break; - } -out_unlock: - mutex_unlock(&cpuset_mutex); - return retval; -} - -static int cpuset_write_s64(struct cgroup *cgrp, struct cftype *cft, s64 val) -{ - struct cpuset *cs = cgroup_cs(cgrp); - cpuset_filetype_t type = cft->private; - int retval = -ENODEV; - - mutex_lock(&cpuset_mutex); - if (!is_cpuset_online(cs)) - goto out_unlock; - - switch (type) { - case FILE_SCHED_RELAX_DOMAIN_LEVEL: - retval = update_relax_domain_level(cs, val); - break; - default: - retval = -EINVAL; - break; - } -out_unlock: - mutex_unlock(&cpuset_mutex); - return retval; -} - -/* - * Common handling for a write to a "cpus" or "mems" file. - */ -static int cpuset_write_resmask(struct cgroup *cgrp, struct cftype *cft, - const char *buf) -{ - struct cpuset *cs = cgroup_cs(cgrp); - struct cpuset *trialcs; - int retval = -ENODEV; - - /* - * CPU or memory hotunplug may leave @cs w/o any execution - * resources, in which case the hotplug code asynchronously updates - * configuration and transfers all tasks to the nearest ancestor - * which can execute. - * - * As writes to "cpus" or "mems" may restore @cs's execution - * resources, wait for the previously scheduled operations before - * proceeding, so that we don't end up keep removing tasks added - * after execution capability is restored. - */ - flush_work(&cpuset_hotplug_work); - - mutex_lock(&cpuset_mutex); - if (!is_cpuset_online(cs)) - goto out_unlock; - - trialcs = alloc_trial_cpuset(cs); - if (!trialcs) { - retval = -ENOMEM; - goto out_unlock; - } - - switch (cft->private) { - case FILE_CPULIST: - retval = update_cpumask(cs, trialcs, buf); - break; - case FILE_MEMLIST: - retval = update_nodemask(cs, trialcs, buf); - break; - default: - retval = -EINVAL; - break; - } - - free_trial_cpuset(trialcs); -out_unlock: - mutex_unlock(&cpuset_mutex); - 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 size_t cpuset_sprintf_cpulist(char *page, struct cpuset *cs) -{ - size_t count; - - mutex_lock(&callback_mutex); - count = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed); - mutex_unlock(&callback_mutex); - - return count; -} - -static size_t cpuset_sprintf_memlist(char *page, struct cpuset *cs) -{ - size_t count; - - mutex_lock(&callback_mutex); - count = nodelist_scnprintf(page, PAGE_SIZE, cs->mems_allowed); - mutex_unlock(&callback_mutex); - - return count; -} - -static ssize_t cpuset_common_file_read(struct cgroup *cgrp, - struct cftype *cft, - struct file *file, - char __user *buf, - size_t nbytes, loff_t *ppos) -{ - struct cpuset *cs = cgroup_cs(cgrp); - 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; - 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; -} - -static u64 cpuset_read_u64(struct cgroup *cgrp, struct cftype *cft) -{ - struct cpuset *cs = cgroup_cs(cgrp); - cpuset_filetype_t type = cft->private; - switch (type) { - case FILE_CPU_EXCLUSIVE: - return is_cpu_exclusive(cs); - case FILE_MEM_EXCLUSIVE: - return is_mem_exclusive(cs); - case FILE_MEM_HARDWALL: - return is_mem_hardwall(cs); - case FILE_SCHED_LOAD_BALANCE: - return is_sched_load_balance(cs); - case FILE_MEMORY_MIGRATE: - return is_memory_migrate(cs); - case FILE_MEMORY_PRESSURE_ENABLED: - return cpuset_memory_pressure_enabled; - case FILE_MEMORY_PRESSURE: - return fmeter_getrate(&cs->fmeter); - case FILE_SPREAD_PAGE: - return is_spread_page(cs); - case FILE_SPREAD_SLAB: - return is_spread_slab(cs); - default: - BUG(); - } - - /* Unreachable but makes gcc happy */ - return 0; -} - -static s64 cpuset_read_s64(struct cgroup *cgrp, struct cftype *cft) -{ - struct cpuset *cs = cgroup_cs(cgrp); - cpuset_filetype_t type = cft->private; - switch (type) { - case FILE_SCHED_RELAX_DOMAIN_LEVEL: - return cs->relax_domain_level; - default: - BUG(); - } - - /* Unrechable but makes gcc happy */ - return 0; -} - - -/* - * for the common functions, 'private' gives the type of file - */ - -static struct cftype files[] = { - { - .name = "cpus", - .read = cpuset_common_file_read, - .write_string = cpuset_write_resmask, - .max_write_len = (100U + 6 * NR_CPUS), - .private = FILE_CPULIST, - }, - - { - .name = "mems", - .read = cpuset_common_file_read, - .write_string = cpuset_write_resmask, - .max_write_len = (100U + 6 * MAX_NUMNODES), - .private = FILE_MEMLIST, - }, - - { - .name = "cpu_exclusive", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_CPU_EXCLUSIVE, - }, - - { - .name = "mem_exclusive", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_MEM_EXCLUSIVE, - }, - - { - .name = "mem_hardwall", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_MEM_HARDWALL, - }, - - { - .name = "sched_load_balance", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_SCHED_LOAD_BALANCE, - }, - - { - .name = "sched_relax_domain_level", - .read_s64 = cpuset_read_s64, - .write_s64 = cpuset_write_s64, - .private = FILE_SCHED_RELAX_DOMAIN_LEVEL, - }, - - { - .name = "memory_migrate", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_MEMORY_MIGRATE, - }, - - { - .name = "memory_pressure", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_MEMORY_PRESSURE, - .mode = S_IRUGO, - }, - - { - .name = "memory_spread_page", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_SPREAD_PAGE, - }, - - { - .name = "memory_spread_slab", - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_SPREAD_SLAB, - }, - - { - .name = "memory_pressure_enabled", - .flags = CFTYPE_ONLY_ON_ROOT, - .read_u64 = cpuset_read_u64, - .write_u64 = cpuset_write_u64, - .private = FILE_MEMORY_PRESSURE_ENABLED, - }, - - { } /* terminate */ -}; - -/* - * cpuset_css_alloc - allocate a cpuset css - * cgrp: control group that the new cpuset will be part of - */ - -static struct cgroup_subsys_state *cpuset_css_alloc(struct cgroup *cgrp) -{ - struct cpuset *cs; - - if (!cgrp->parent) - return &top_cpuset.css; - - cs = kzalloc(sizeof(*cs), GFP_KERNEL); - if (!cs) - return ERR_PTR(-ENOMEM); - if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL)) { - kfree(cs); - return ERR_PTR(-ENOMEM); - } - - set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); - cpumask_clear(cs->cpus_allowed); - nodes_clear(cs->mems_allowed); - fmeter_init(&cs->fmeter); - cs->relax_domain_level = -1; - - return &cs->css; -} - -static int cpuset_css_online(struct cgroup *cgrp) -{ - struct cpuset *cs = cgroup_cs(cgrp); - struct cpuset *parent = parent_cs(cs); - struct cpuset *tmp_cs; - struct cgroup *pos_cg; - - if (!parent) - return 0; - - mutex_lock(&cpuset_mutex); - - set_bit(CS_ONLINE, &cs->flags); - if (is_spread_page(parent)) - set_bit(CS_SPREAD_PAGE, &cs->flags); - if (is_spread_slab(parent)) - set_bit(CS_SPREAD_SLAB, &cs->flags); - - number_of_cpusets++; - - if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags)) - goto out_unlock; - - /* - * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is - * set. This flag handling is implemented in cgroup core for - * histrical reasons - the flag may be specified during mount. - * - * Currently, if any sibling cpusets have exclusive cpus or mem, we - * refuse to clone the configuration - thereby refusing the task to - * be entered, and as a result refusing the sys_unshare() or - * clone() which initiated it. If this becomes a problem for some - * users who wish to allow that scenario, then this could be - * changed to grant parent->cpus_allowed-sibling_cpus_exclusive - * (and likewise for mems) to the new cgroup. - */ - rcu_read_lock(); - cpuset_for_each_child(tmp_cs, pos_cg, parent) { - if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) { - rcu_read_unlock(); - goto out_unlock; - } - } - rcu_read_unlock(); - - mutex_lock(&callback_mutex); - cs->mems_allowed = parent->mems_allowed; - cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); - mutex_unlock(&callback_mutex); -out_unlock: - mutex_unlock(&cpuset_mutex); - return 0; -} - -static void cpuset_css_offline(struct cgroup *cgrp) -{ - struct cpuset *cs = cgroup_cs(cgrp); - - mutex_lock(&cpuset_mutex); - - if (is_sched_load_balance(cs)) - update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); - - number_of_cpusets--; - clear_bit(CS_ONLINE, &cs->flags); - - mutex_unlock(&cpuset_mutex); -} - -/* - * 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_locked(). - */ - -static void cpuset_css_free(struct cgroup *cgrp) -{ - struct cpuset *cs = cgroup_cs(cgrp); - - free_cpumask_var(cs->cpus_allowed); - kfree(cs); -} - -struct cgroup_subsys cpuset_subsys = { - .name = "cpuset", - .css_alloc = cpuset_css_alloc, - .css_online = cpuset_css_online, - .css_offline = cpuset_css_offline, - .css_free = cpuset_css_free, - .can_attach = cpuset_can_attach, - .cancel_attach = cpuset_cancel_attach, - .attach = cpuset_attach, - .subsys_id = cpuset_subsys_id, - .base_cftypes = files, - .early_init = 1, -}; - -/** - * 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; - - if (!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)) - BUG(); - - cpumask_setall(top_cpuset.cpus_allowed); - nodes_setall(top_cpuset.mems_allowed); - - fmeter_init(&top_cpuset.fmeter); - set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); - top_cpuset.relax_domain_level = -1; - - err = register_filesystem(&cpuset_fs_type); - if (err < 0) - return err; - - if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)) - BUG(); - - number_of_cpusets = 1; - return 0; -} - -/* - * If CPU and/or memory hotplug handlers, below, unplug 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 move the tasks in the empty - * cpuset to its next-highest non-empty parent. - */ -static void remove_tasks_in_empty_cpuset(struct cpuset *cs) -{ - struct cpuset *parent; - - /* - * Find its next-highest non-empty parent, (top cpuset - * has online cpus, so can't be empty). - */ - parent = parent_cs(cs); - while (cpumask_empty(parent->cpus_allowed) || - nodes_empty(parent->mems_allowed)) - parent = parent_cs(parent); - - if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) { - rcu_read_lock(); - printk(KERN_ERR "cpuset: failed to transfer tasks out of empty cpuset %s\n", - cgroup_name(cs->css.cgroup)); - rcu_read_unlock(); - } -} - -/** - * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug - * @cs: cpuset in interest - * - * Compare @cs's cpu and mem masks against top_cpuset and if some have gone - * offline, update @cs accordingly. If @cs ends up with no CPU or memory, - * all its tasks are moved to the nearest ancestor with both resources. - */ -static void cpuset_hotplug_update_tasks(struct cpuset *cs) -{ - static cpumask_t off_cpus; - static nodemask_t off_mems; - bool is_empty; - bool sane = cgroup_sane_behavior(cs->css.cgroup); - -retry: - wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); - - mutex_lock(&cpuset_mutex); - - /* - * We have raced with task attaching. We wait until attaching - * is finished, so we won't attach a task to an empty cpuset. - */ - if (cs->attach_in_progress) { - mutex_unlock(&cpuset_mutex); - goto retry; - } - - cpumask_andnot(&off_cpus, cs->cpus_allowed, top_cpuset.cpus_allowed); - nodes_andnot(off_mems, cs->mems_allowed, top_cpuset.mems_allowed); - - mutex_lock(&callback_mutex); - cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus); - mutex_unlock(&callback_mutex); - - /* - * If sane_behavior flag is set, we need to update tasks' cpumask - * for empty cpuset to take on ancestor's cpumask. Otherwise, don't - * call update_tasks_cpumask() if the cpuset becomes empty, as - * the tasks in it will be migrated to an ancestor. - */ - if ((sane && cpumask_empty(cs->cpus_allowed)) || - (!cpumask_empty(&off_cpus) && !cpumask_empty(cs->cpus_allowed))) - update_tasks_cpumask(cs, NULL); - - mutex_lock(&callback_mutex); - nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems); - mutex_unlock(&callback_mutex); - - /* - * If sane_behavior flag is set, we need to update tasks' nodemask - * for empty cpuset to take on ancestor's nodemask. Otherwise, don't - * call update_tasks_nodemask() if the cpuset becomes empty, as - * the tasks in it will be migratd to an ancestor. - */ - if ((sane && nodes_empty(cs->mems_allowed)) || - (!nodes_empty(off_mems) && !nodes_empty(cs->mems_allowed))) - update_tasks_nodemask(cs, NULL); - - is_empty = cpumask_empty(cs->cpus_allowed) || - nodes_empty(cs->mems_allowed); - - mutex_unlock(&cpuset_mutex); - - /* - * If sane_behavior flag is set, we'll keep tasks in empty cpusets. - * - * Otherwise move tasks to the nearest ancestor with execution - * resources. This is full cgroup operation which will - * also call back into cpuset. Should be done outside any lock. - */ - if (!sane && is_empty) - remove_tasks_in_empty_cpuset(cs); -} - -/** - * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset - * - * This function is called after either CPU or memory configuration has - * changed and updates cpuset accordingly. The top_cpuset is always - * synchronized to cpu_active_mask and N_MEMORY, which 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. - * - * Non-root cpusets are only affected by offlining. If any CPUs or memory - * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on - * all descendants. - * - * Note that CPU offlining during suspend is ignored. We don't modify - * cpusets across suspend/resume cycles at all. - */ -static void cpuset_hotplug_workfn(struct work_struct *work) -{ - static cpumask_t new_cpus; - static nodemask_t new_mems; - bool cpus_updated, mems_updated; - - mutex_lock(&cpuset_mutex); - - /* fetch the available cpus/mems and find out which changed how */ - cpumask_copy(&new_cpus, cpu_active_mask); - new_mems = node_states[N_MEMORY]; - - cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus); - mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems); - - /* synchronize cpus_allowed to cpu_active_mask */ - if (cpus_updated) { - mutex_lock(&callback_mutex); - cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); - mutex_unlock(&callback_mutex); - /* we don't mess with cpumasks of tasks in top_cpuset */ - } - - /* synchronize mems_allowed to N_MEMORY */ - if (mems_updated) { - mutex_lock(&callback_mutex); - top_cpuset.mems_allowed = new_mems; - mutex_unlock(&callback_mutex); - update_tasks_nodemask(&top_cpuset, NULL); - } - - mutex_unlock(&cpuset_mutex); - - /* if cpus or mems changed, we need to propagate to descendants */ - if (cpus_updated || mems_updated) { - struct cpuset *cs; - struct cgroup *pos_cgrp; - - rcu_read_lock(); - cpuset_for_each_descendant_pre(cs, pos_cgrp, &top_cpuset) { - if (!css_tryget(&cs->css)) - continue; - rcu_read_unlock(); - - cpuset_hotplug_update_tasks(cs); - - rcu_read_lock(); - css_put(&cs->css); - } - rcu_read_unlock(); - } - - /* rebuild sched domains if cpus_allowed has changed */ - if (cpus_updated) - rebuild_sched_domains(); -} - -void cpuset_update_active_cpus(bool cpu_online) -{ - /* - * We're inside cpu hotplug critical region which usually nests - * inside cgroup synchronization. Bounce actual hotplug processing - * to a work item to avoid reverse locking order. - * - * We still need to do partition_sched_domains() synchronously; - * otherwise, the scheduler will get confused and put tasks to the - * dead CPU. Fall back to the default single domain. - * cpuset_hotplug_workfn() will rebuild it as necessary. - */ - partition_sched_domains(1, NULL, NULL); - schedule_work(&cpuset_hotplug_work); -} - -/* - * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. - * Call this routine anytime after node_states[N_MEMORY] changes. - * See cpuset_update_active_cpus() for CPU hotplug handling. - */ -static int cpuset_track_online_nodes(struct notifier_block *self, - unsigned long action, void *arg) -{ - schedule_work(&cpuset_hotplug_work); - return NOTIFY_OK; -} - -static struct notifier_block cpuset_track_online_nodes_nb = { - .notifier_call = cpuset_track_online_nodes, - .priority = 10, /* ??! */ -}; - -/** - * cpuset_init_smp - initialize cpus_allowed - * - * Description: Finish top cpuset after cpu, node maps are initialized - */ -void __init cpuset_init_smp(void) -{ - cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); - top_cpuset.mems_allowed = node_states[N_MEMORY]; - top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; - - register_hotmemory_notifier(&cpuset_track_online_nodes_nb); -} - -/** - * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. - * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. - * @pmask: pointer to struct cpumask variable to receive cpus_allowed set. - * - * Description: Returns the cpumask_var_t cpus_allowed of the cpuset - * attached to the specified @tsk. Guaranteed to return some non-empty - * subset of cpu_online_mask, even if this means going outside the - * tasks cpuset. - **/ - -void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) -{ - struct cpuset *cpus_cs; - - mutex_lock(&callback_mutex); - task_lock(tsk); - cpus_cs = effective_cpumask_cpuset(task_cs(tsk)); - guarantee_online_cpus(cpus_cs, pmask); - task_unlock(tsk); - mutex_unlock(&callback_mutex); -} - -void cpuset_cpus_allowed_fallback(struct task_struct *tsk) -{ - const struct cpuset *cpus_cs; - - rcu_read_lock(); - cpus_cs = effective_cpumask_cpuset(task_cs(tsk)); - do_set_cpus_allowed(tsk, cpus_cs->cpus_allowed); - rcu_read_unlock(); - - /* - * We own tsk->cpus_allowed, nobody can change it under us. - * - * But we used cs && cs->cpus_allowed lockless and thus can - * race with cgroup_attach_task() or update_cpumask() and get - * the wrong tsk->cpus_allowed. However, both cases imply the - * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr() - * which takes task_rq_lock(). - * - * If we are called after it dropped the lock we must see all - * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary - * set any mask even if it is not right from task_cs() pov, - * the pending set_cpus_allowed_ptr() will fix things. - * - * select_fallback_rq() will fix things ups and set cpu_possible_mask - * if required. - */ -} - -void cpuset_init_current_mems_allowed(void) -{ - nodes_setall(current->mems_allowed); -} - -/** - * 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_MEMORY], even if this means going outside the - * tasks cpuset. - **/ - -nodemask_t cpuset_mems_allowed(struct task_struct *tsk) -{ - struct cpuset *mems_cs; - nodemask_t mask; - - mutex_lock(&callback_mutex); - task_lock(tsk); - mems_cs = effective_nodemask_cpuset(task_cs(tsk)); - guarantee_online_mems(mems_cs, &mask); - task_unlock(tsk); - mutex_unlock(&callback_mutex); - - return mask; -} - -/** - * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed - * @nodemask: the nodemask to be checked - * - * Are any of the nodes in the nodemask allowed in current->mems_allowed? - */ -int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) -{ - return nodes_intersects(*nodemask, current->mems_allowed); -} - -/* - * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or - * mem_hardwall ancestor to the specified cpuset. Call holding - * callback_mutex. If no ancestor is mem_exclusive or mem_hardwall - * (an unusual configuration), then returns the root cpuset. - */ -static const struct cpuset *nearest_hardwall_ancestor(const struct cpuset *cs) -{ - while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs)) - cs = parent_cs(cs); - return cs; -} - -/** - * cpuset_node_allowed_softwall - Can we allocate on a memory node? - * @node: is this 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 node is in our task's mems_allowed, - * yes. If it's not a __GFP_HARDWALL request and this node is in the nearest - * hardwalled cpuset ancestor to this task's 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_node_allowed_softwall() reduces to - * cpuset_node_allowed_hardwall(). Otherwise, cpuset_node_allowed_softwall() - * might sleep, and might allow a node from an enclosing cpuset. - * - * cpuset_node_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 hardwalled 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 hardwalled cpuset ok - * GFP_USER - only nodes in current tasks mems allowed ok. - * - * Rule: - * Don't call cpuset_node_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_node_allowed_softwall(int node, gfp_t gfp_mask) -{ - const struct cpuset *cs; /* current cpuset ancestors */ - int allowed; /* is allocation in zone z allowed? */ - - if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) - return 1; - 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_hardwall_ancestor(task_cs(current)); - task_unlock(current); - - allowed = node_isset(node, cs->mems_allowed); - mutex_unlock(&callback_mutex); - return allowed; -} - -/* - * cpuset_node_allowed_hardwall - Can we allocate on a memory node? - * @node: is this 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 node is in our task's 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_node_allowed_softwall() variant, above, - * this variant requires that the node be in the current task's - * 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_node_allowed_hardwall(int node, gfp_t gfp_mask) -{ - if (in_interrupt() || (gfp_mask & __GFP_THISNODE)) - return 1; - 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_mem_spread_node() - On which node to begin search for a file page - * cpuset_slab_spread_node() - On which node to begin search for a slab 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(). - */ - -static int cpuset_spread_node(int *rotor) -{ - int node; - - node = next_node(*rotor, current->mems_allowed); - if (node == MAX_NUMNODES) - node = first_node(current->mems_allowed); - *rotor = node; - return node; -} - -int cpuset_mem_spread_node(void) -{ - if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE) - current->cpuset_mem_spread_rotor = - node_random(¤t->mems_allowed); - - return cpuset_spread_node(¤t->cpuset_mem_spread_rotor); -} - -int cpuset_slab_spread_node(void) -{ - if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE) - current->cpuset_slab_spread_rotor = - node_random(¤t->mems_allowed); - - return cpuset_spread_node(¤t->cpuset_slab_spread_rotor); -} - -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); -} - -#define CPUSET_NODELIST_LEN (256) - -/** - * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed - * @task: pointer to task_struct of some task. - * - * Description: Prints @task's name, cpuset name, and cached copy of its - * mems_allowed to the kernel log. Must hold task_lock(task) to allow - * dereferencing task_cs(task). - */ -void cpuset_print_task_mems_allowed(struct task_struct *tsk) -{ - /* Statically allocated to prevent using excess stack. */ - static char cpuset_nodelist[CPUSET_NODELIST_LEN]; - static DEFINE_SPINLOCK(cpuset_buffer_lock); - - struct cgroup *cgrp = task_cs(tsk)->css.cgroup; - - rcu_read_lock(); - spin_lock(&cpuset_buffer_lock); - - nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN, - tsk->mems_allowed); - printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n", - tsk->comm, cgroup_name(cgrp), cpuset_nodelist); - - spin_unlock(&cpuset_buffer_lock); - rcu_read_unlock(); -} - -/* - * 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 cpuset_mutex, keeping cpuset_attach() from changing it - * anyway. - */ -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; - - rcu_read_lock(); - css = task_subsys_state(tsk, cpuset_subsys_id); - retval = cgroup_path(css->cgroup, buf, PAGE_SIZE); - rcu_read_unlock(); - if (retval < 0) - goto out_put_task; - seq_puts(m, buf); - seq_putc(m, '\n'); -out_put_task: - put_task_struct(tsk); -out_free: - kfree(buf); -out: - return retval; -} -#endif /* CONFIG_PROC_PID_CPUSET */ - -/* Display task mems_allowed in /proc/<pid>/status file. */ -void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task) -{ - seq_printf(m, "Mems_allowed:\t"); - seq_nodemask(m, &task->mems_allowed); - seq_printf(m, "\n"); - seq_printf(m, "Mems_allowed_list:\t"); - seq_nodemask_list(m, &task->mems_allowed); - seq_printf(m, "\n"); -} |