* 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
#include <linux/list.h>
#include <linux/mempolicy.h>
#include <linux/mm.h>
+#include <linux/memory.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/sort.h>
#include <asm/uaccess.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
#include <linux/mutex.h>
-#include <linux/kfifo.h>
#include <linux/workqueue.h>
#include <linux/cgroup.h>
+/*
+ * Workqueue for cpuset related tasks.
+ *
+ * Using kevent workqueue may cause deadlock when memory_migrate
+ * is set. So we create a separate workqueue thread for cpuset.
+ */
+static struct workqueue_struct *cpuset_wq;
+
/*
* Tracks how many cpusets are currently defined in system.
* When there is only one cpuset (the root cpuset) we can
struct cgroup_subsys_state css;
unsigned long flags; /* "unsigned long" so bitops work */
- cpumask_t cpus_allowed; /* CPUs allowed to tasks in cpuset */
+ cpumask_var_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() */
/* for custom sched domain */
int relax_domain_level;
- /* used for walking a cpuset heirarchy */
+ /* used for walking a cpuset hierarchy */
struct list_head stack_list;
};
return container_of(task_subsys_state(task, cpuset_subsys_id),
struct cpuset, css);
}
-struct cpuset_hotplug_scanner {
- struct cgroup_scanner scan;
- struct cgroup *to;
-};
/* bits in struct cpuset flags field */
typedef enum {
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 cpuset_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 another's 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 writes to cpuset_mems_generation are guarded by the cgroup lock
- * 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,
};
/*
* 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.
- *
- * The cpuset_common_file_write handler for operations that modify
- * the cpuset hierarchy holds cgroup_mutex across the entire operation,
- * single threading all such cpuset modifications across the system.
+ * 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
static DEFINE_MUTEX(callback_mutex);
-/* This is ugly, but preserves the userspace API for existing cpuset
+/*
+ * cpuset_buffer_lock protects both the cpuset_name and cpuset_nodelist
+ * buffers. They are statically allocated to prevent using excess stack
+ * when calling cpuset_print_task_mems_allowed().
+ */
+#define CPUSET_NAME_LEN (128)
+#define CPUSET_NODELIST_LEN (256)
+static char cpuset_name[CPUSET_NAME_LEN];
+static char cpuset_nodelist[CPUSET_NODELIST_LEN];
+static DEFINE_SPINLOCK(cpuset_buffer_lock);
+
+/*
+ * 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)
+ * 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");
- int ret = -ENODEV;
+ struct dentry *ret = ERR_PTR(-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);
+ 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",
- .get_sb = cpuset_get_sb,
+ .mount = cpuset_mount,
};
/*
- * Return in *pmask the portion of a cpusets's cpus_allowed that
+ * 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,
* Call with callback_mutex held.
*/
-static void guarantee_online_cpus(const struct cpuset *cs, cpumask_t *pmask)
+static void guarantee_online_cpus(const struct cpuset *cs,
+ struct cpumask *pmask)
{
- while (cs && !cpus_intersects(cs->cpus_allowed, cpu_online_map))
+ while (cs && !cpumask_intersects(cs->cpus_allowed, cpu_online_mask))
cs = cs->parent;
if (cs)
- cpus_and(*pmask, cs->cpus_allowed, cpu_online_map);
+ cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask);
else
- *pmask = cpu_online_map;
- BUG_ON(!cpus_intersects(*pmask, cpu_online_map));
+ cpumask_copy(pmask, cpu_online_mask);
+ BUG_ON(!cpumask_intersects(pmask, cpu_online_mask));
}
/*
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 cgroup_mutex held. Thanks in part to
- * 'the_top_cpuset_hack', the task's cpuset pointer will never
- * be NULL. This routine also might acquire callback_mutex 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 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.
+/*
+ * update task's spread flag if cpuset's page/slab spread flag is set
+ *
+ * Called with callback_mutex/cgroup_mutex held
*/
-
-void cpuset_update_task_memory_state(void)
+static void cpuset_update_task_spread_flag(struct cpuset *cs,
+ struct task_struct *tsk)
{
- 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);
- }
+ 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;
}
/*
static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
{
- return cpus_subset(p->cpus_allowed, q->cpus_allowed) &&
+ 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.
c = cgroup_cs(cont);
if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
c != cur &&
- cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
+ cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
return -EINVAL;
if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
c != cur &&
/* 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) ||
+ if (cpumask_empty(trial->cpus_allowed) ||
nodes_empty(trial->mems_allowed)) {
return -ENOSPC;
}
return 0;
}
+#ifdef CONFIG_SMP
/*
- * Helper routine for rebuild_sched_domains().
+ * 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 cpus_intersects(a->cpus_allowed, b->cpus_allowed);
+ return cpumask_intersects(a->cpus_allowed, b->cpus_allowed);
}
static void
update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
{
- if (!dattr)
- return;
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 *c)
+{
+ LIST_HEAD(q);
+
+ list_add(&c->stack_list, &q);
+ while (!list_empty(&q)) {
+ struct cpuset *cp;
+ struct cgroup *cont;
+ struct cpuset *child;
+
+ cp = list_first_entry(&q, struct cpuset, stack_list);
+ list_del(q.next);
+
+ if (cpumask_empty(cp->cpus_allowed))
+ continue;
+
+ if (is_sched_load_balance(cp))
+ update_domain_attr(dattr, cp);
+
+ list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
+ child = cgroup_cs(cont);
+ list_add_tail(&child->stack_list, &q);
+ }
+ }
+}
+
/*
- * rebuild_sched_domains()
+ * generate_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.
+ * 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.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/cpusets.txt
+ * 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
* 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 get_online_cpus()/put_online_cpus() pair.
- * Must not be called holding callback_mutex, because we must not
- * call get_online_cpus() while holding callback_mutex. Elsewhere
- * the kernel nests callback_mutex inside get_online_cpus() calls.
- * So the reverse nesting would risk an ABBA deadlock.
+ * Must be called with cgroup_lock held.
*
* The three key local variables below are:
- * q - a kfifo queue of cpuset pointers, used to implement a
+ * 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
* element of the partition (one sched domain) to be passed to
* partition_sched_domains().
*/
-
-void rebuild_sched_domains(void)
+static int generate_sched_domains(cpumask_var_t **domains,
+ struct sched_domain_attr **attributes)
{
- struct kfifo *q; /* queue of cpusets to be scanned */
+ LIST_HEAD(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 */
+ cpumask_var_t *doms; /* resulting partition; i.e. sched domains */
struct sched_domain_attr *dattr; /* attributes for custom domains */
- int ndoms; /* number of sched domains in result */
- int nslot; /* next empty doms[] cpumask_t slot */
+ int ndoms = 0; /* number of sched domains in result */
+ int nslot; /* next empty doms[] struct cpumask slot */
- q = NULL;
- csa = NULL;
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 = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
+ doms = alloc_sched_domains(ndoms);
if (!doms)
- goto rebuild;
+ goto done;
+
dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
if (dattr) {
*dattr = SD_ATTR_INIT;
- update_domain_attr(dattr, &top_cpuset);
+ update_domain_attr_tree(dattr, &top_cpuset);
}
- *doms = top_cpuset.cpus_allowed;
- goto rebuild;
- }
+ cpumask_copy(doms[0], top_cpuset.cpus_allowed);
- 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))) {
+ list_add(&top_cpuset.stack_list, &q);
+ while (!list_empty(&q)) {
struct cgroup *cont;
struct cpuset *child; /* scans child cpusets of cp */
- if (is_sched_load_balance(cp))
+
+ cp = list_first_entry(&q, struct cpuset, stack_list);
+ list_del(q.next);
+
+ if (cpumask_empty(cp->cpus_allowed))
+ continue;
+
+ /*
+ * 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 (is_sched_load_balance(cp)) {
csa[csn++] = cp;
+ continue;
+ }
+
list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
child = cgroup_cs(cont);
- __kfifo_put(q, (void *)&child, sizeof(cp));
+ list_add_tail(&child->stack_list, &q);
}
}
}
}
- /* Convert <csn, csa> to <ndoms, doms> */
- doms = kmalloc(ndoms * sizeof(cpumask_t), GFP_KERNEL);
+ /*
+ * 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 rebuild;
+ 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) {
- 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;
+ 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;
+ }
- cpus_clear(*dp);
- if (dattr)
- *(dattr + nslot) = SD_ATTR_INIT;
- 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;
- if (dattr)
- update_domain_attr(dattr
- + nslot, b);
- }
+ 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++;
}
+ nslot++;
}
BUG_ON(nslot != ndoms);
-rebuild:
- /* Have scheduler rebuild sched domains */
+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.
+ *
+ * Call with neither cgroup_mutex held nor within get_online_cpus().
+ * Takes both cgroup_mutex and get_online_cpus().
+ *
+ * Cannot be directly called from cpuset code handling changes
+ * to the cpuset pseudo-filesystem, because it cannot be called
+ * from code that already holds cgroup_mutex.
+ */
+static void do_rebuild_sched_domains(struct work_struct *unused)
+{
+ struct sched_domain_attr *attr;
+ cpumask_var_t *doms;
+ int ndoms;
+
get_online_cpus();
- partition_sched_domains(ndoms, doms, dattr);
+
+ /* Generate domain masks and attrs */
+ cgroup_lock();
+ ndoms = generate_sched_domains(&doms, &attr);
+ cgroup_unlock();
+
+ /* Have scheduler rebuild the domains */
+ partition_sched_domains(ndoms, doms, attr);
+
put_online_cpus();
+}
+#else /* !CONFIG_SMP */
+static void do_rebuild_sched_domains(struct work_struct *unused)
+{
+}
-done:
- if (q && !IS_ERR(q))
- kfifo_free(q);
- kfree(csa);
- /* Don't kfree(doms) -- partition_sched_domains() does that. */
- /* Don't kfree(dattr) -- partition_sched_domains() does that. */
+static int generate_sched_domains(cpumask_var_t **domains,
+ struct sched_domain_attr **attributes)
+{
+ *domains = NULL;
+ return 1;
}
+#endif /* CONFIG_SMP */
-static inline int started_after_time(struct task_struct *t1,
- struct timespec *time,
- struct task_struct *t2)
+static DECLARE_WORK(rebuild_sched_domains_work, do_rebuild_sched_domains);
+
+/*
+ * Rebuild scheduler domains, asynchronously via workqueue.
+ *
+ * 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.
+ *
+ * The rebuild_sched_domains() and partition_sched_domains()
+ * routines must nest cgroup_lock() inside get_online_cpus(),
+ * but such cpuset changes as these must nest that locking the
+ * other way, holding cgroup_lock() for much of the code.
+ *
+ * So in order to avoid an ABBA deadlock, the cpuset code handling
+ * these user changes delegates the actual sched domain rebuilding
+ * to a separate workqueue thread, which ends up processing the
+ * above do_rebuild_sched_domains() function.
+ */
+static void async_rebuild_sched_domains(void)
{
- 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;
- }
+ queue_work(cpuset_wq, &rebuild_sched_domains_work);
}
-static inline int started_after(void *p1, void *p2)
+/*
+ * Accomplishes the same scheduler domain rebuild as the above
+ * async_rebuild_sched_domains(), however it directly calls the
+ * rebuild routine synchronously rather than calling it via an
+ * asynchronous work thread.
+ *
+ * This can only be called from code that is not holding
+ * cgroup_mutex (not nested in a cgroup_lock() call.)
+ */
+void rebuild_sched_domains(void)
{
- struct task_struct *t1 = p1;
- struct task_struct *t2 = p2;
- return started_after_time(t1, &t2->start_time, t2);
+ do_rebuild_sched_domains(NULL);
}
/**
static int cpuset_test_cpumask(struct task_struct *tsk,
struct cgroup_scanner *scan)
{
- return !cpus_equal(tsk->cpus_allowed,
+ return !cpumask_equal(&tsk->cpus_allowed,
(cgroup_cs(scan->cg))->cpus_allowed);
}
static void cpuset_change_cpumask(struct task_struct *tsk,
struct cgroup_scanner *scan)
{
- set_cpus_allowed_ptr(tsk, &((cgroup_cs(scan->cg))->cpus_allowed));
+ set_cpus_allowed_ptr(tsk, ((cgroup_cs(scan->cg))->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 cgroup_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 = cpuset_test_cpumask;
+ scan.process_task = cpuset_change_cpumask;
+ scan.heap = heap;
+ cgroup_scan_tasks(&scan);
}
/**
* @cs: the cpuset to consider
* @buf: buffer of cpu numbers written to this cpuset
*/
-static int update_cpumask(struct cpuset *cs, char *buf)
+static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
+ const char *buf)
{
- struct cpuset trialcs;
- struct cgroup_scanner scan;
struct ptr_heap heap;
int retval;
int is_load_balanced;
if (cs == &top_cpuset)
return -EACCES;
- trialcs = *cs;
-
/*
* 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.
*/
- buf = strstrip(buf);
if (!*buf) {
- cpus_clear(trialcs.cpus_allowed);
+ cpumask_clear(trialcs->cpus_allowed);
} else {
- retval = cpulist_parse(buf, trialcs.cpus_allowed);
+ retval = cpulist_parse(buf, trialcs->cpus_allowed);
if (retval < 0)
return retval;
- if (!cpus_subset(trialcs.cpus_allowed, cpu_online_map))
+ if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask))
return -EINVAL;
}
- retval = validate_change(cs, &trialcs);
+ 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))
+ if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
return 0;
- retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, &started_after);
+ retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
if (retval)
return retval;
- is_load_balanced = is_sched_load_balance(&trialcs);
+ is_load_balanced = is_sched_load_balance(trialcs);
mutex_lock(&callback_mutex);
- cs->cpus_allowed = trialcs.cpus_allowed;
+ cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
mutex_unlock(&callback_mutex);
/*
* Scan tasks in the cpuset, and update the cpumasks of any
* that need an update.
*/
- scan.cg = cs->css.cgroup;
- scan.test_task = cpuset_test_cpumask;
- scan.process_task = cpuset_change_cpumask;
- scan.heap = &heap;
- cgroup_scan_tasks(&scan);
+ update_tasks_cpumask(cs, &heap);
+
heap_free(&heap);
if (is_load_balanced)
- rebuild_sched_domains();
+ async_rebuild_sched_domains();
return 0;
}
* call to guarantee_online_mems(), as we know no one is changing
* our task's 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,
{
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);
+}
+
+/*
+ * 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)
+{
+repeat:
+ /*
+ * 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);
+ nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
+ mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP1);
+
+
+ /*
+ * ensure checking ->mems_allowed_change_disable after setting all new
+ * allowed nodes.
+ *
+ * the read-side task can see an nodemask with new allowed nodes and
+ * old allowed nodes. and if it allocates page when cpuset clears newly
+ * disallowed ones continuous, it can see the new allowed bits.
+ *
+ * And if setting all new allowed nodes is after the checking, setting
+ * all new allowed nodes and clearing newly disallowed ones will be done
+ * continuous, and the read-side task may find no node to alloc page.
+ */
+ smp_mb();
+
+ /*
+ * Allocation of memory is very fast, we needn't sleep when waiting
+ * for the read-side.
+ */
+ while (ACCESS_ONCE(tsk->mems_allowed_change_disable)) {
+ task_unlock(tsk);
+ if (!task_curr(tsk))
+ yield();
+ goto repeat;
+ }
+
+ /*
+ * ensure checking ->mems_allowed_change_disable before clearing all new
+ * disallowed nodes.
+ *
+ * if clearing newly disallowed bits before the checking, the read-side
+ * task may find no node to alloc page.
+ */
+ smp_mb();
+
+ mpol_rebind_task(tsk, newmems, MPOL_REBIND_STEP2);
+ tsk->mems_allowed = *newmems;
+ 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 cgroup_mutex held.
+ */
+static void cpuset_change_nodemask(struct task_struct *p,
+ struct cgroup_scanner *scan)
+{
+ struct mm_struct *mm;
+ struct cpuset *cs;
+ int migrate;
+ const nodemask_t *oldmem = scan->data;
+ static nodemask_t newmems; /* protected by cgroup_mutex */
+
+ cs = cgroup_cs(scan->cg);
+ guarantee_online_mems(cs, &newmems);
+
+ 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, oldmem, &cs->mems_allowed);
+ 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
+ * @oldmem: old mems_allowed of cpuset cs
+ * @heap: if NULL, defer allocating heap memory to cgroup_scan_tasks()
+ *
+ * Called with cgroup_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, const nodemask_t *oldmem,
+ struct ptr_heap *heap)
+{
+ struct cgroup_scanner scan;
+
+ cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
+
+ scan.cg = cs->css.cgroup;
+ scan.test_task = NULL;
+ scan.process_task = cpuset_change_nodemask;
+ scan.heap = heap;
+ scan.data = (nodemask_t *)oldmem;
+
+ /*
+ * 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 cgroup_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);
+
+ /* We're done rebinding vmas to this cpuset's new mems_allowed. */
+ cpuset_being_rebound = NULL;
}
/*
* 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.
+ * 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 cgroup_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)
+static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
+ const char *buf)
{
- struct cpuset trialcs;
- nodemask_t oldmem;
- struct task_struct *p;
- struct mm_struct **mmarray;
- int i, n, ntasks;
- int migrate;
- int fudge;
+ NODEMASK_ALLOC(nodemask_t, oldmem, GFP_KERNEL);
int retval;
- struct cgroup_iter it;
+ struct ptr_heap heap;
+
+ if (!oldmem)
+ return -ENOMEM;
/*
* top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
* it's read-only
*/
- if (cs == &top_cpuset)
- return -EACCES;
-
- trialcs = *cs;
+ if (cs == &top_cpuset) {
+ retval = -EACCES;
+ goto done;
+ }
/*
* An empty mems_allowed is ok iff there are no tasks in the cpuset.
* that parsing. The validate_change() call ensures that cpusets
* with tasks have memory.
*/
- buf = strstrip(buf);
if (!*buf) {
- nodes_clear(trialcs.mems_allowed);
+ nodes_clear(trialcs->mems_allowed);
} else {
- retval = nodelist_parse(buf, trialcs.mems_allowed);
+ retval = nodelist_parse(buf, trialcs->mems_allowed);
if (retval < 0)
goto done;
- if (!nodes_subset(trialcs.mems_allowed,
- node_states[N_HIGH_MEMORY]))
- return -EINVAL;
+ if (!nodes_subset(trialcs->mems_allowed,
+ node_states[N_HIGH_MEMORY])) {
+ retval = -EINVAL;
+ goto done;
+ }
}
- oldmem = cs->mems_allowed;
- if (nodes_equal(oldmem, trialcs.mems_allowed)) {
+ *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);
+ 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;
- cs->mems_generation = cpuset_mems_generation++;
+ cs->mems_allowed = trialcs->mems_allowed;
mutex_unlock(&callback_mutex);
- cpuset_being_rebound = cs; /* causes mpol_dup() 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;
+ update_tasks_nodemask(cs, oldmem, &heap);
- /* 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;
+ heap_free(&heap);
+done:
+ NODEMASK_FREE(oldmem);
+ return retval;
+}
- 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);
+int current_cpuset_is_being_rebound(void)
+{
+ return task_cs(current) == cpuset_being_rebound;
+}
- /*
- * 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_dup()
- * cpuset_being_rebound check will catch such forks, and rebind
- * their vma mempolicies too. Because we still hold the global
- * cgroup_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];
+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
- mpol_rebind_mm(mm, &cs->mems_allowed);
- if (migrate)
- cpuset_migrate_mm(mm, &oldmem, &cs->mems_allowed);
- mmput(mm);
+ if (val != cs->relax_domain_level) {
+ cs->relax_domain_level = val;
+ if (!cpumask_empty(cs->cpus_allowed) &&
+ is_sched_load_balance(cs))
+ async_rebuild_sched_domains();
}
- /* We're done rebinding vmas to this cpuset's new mems_allowed. */
- kfree(mmarray);
- cpuset_being_rebound = NULL;
- retval = 0;
-done:
- return retval;
+ return 0;
}
-int current_cpuset_is_being_rebound(void)
+/*
+ * 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 cgroup_lock() at this point.
+ */
+static void cpuset_change_flag(struct task_struct *tsk,
+ struct cgroup_scanner *scan)
{
- return task_cs(current) == cpuset_being_rebound;
+ cpuset_update_task_spread_flag(cgroup_cs(scan->cg), tsk);
}
-static int update_relax_domain_level(struct cpuset *cs, s64 val)
+/*
+ * 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 cgroup_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)
{
- if (val < -1 || val >= SD_LV_MAX)
- return -EINVAL;
-
- if (val != cs->relax_domain_level) {
- cs->relax_domain_level = val;
- rebuild_sched_domains();
- }
+ struct cgroup_scanner scan;
- return 0;
+ scan.cg = cs->css.cgroup;
+ scan.test_task = NULL;
+ scan.process_task = cpuset_change_flag;
+ scan.heap = heap;
+ cgroup_scan_tasks(&scan);
}
/*
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
int turning_on)
{
- struct cpuset trialcs;
+ struct cpuset *trialcs;
+ int balance_flag_changed;
+ int spread_flag_changed;
+ struct ptr_heap heap;
int err;
- int cpus_nonempty, balance_flag_changed;
- trialcs = *cs;
+ trialcs = alloc_trial_cpuset(cs);
+ if (!trialcs)
+ return -ENOMEM;
+
if (turning_on)
- set_bit(bit, &trialcs.flags);
+ set_bit(bit, &trialcs->flags);
else
- clear_bit(bit, &trialcs.flags);
+ clear_bit(bit, &trialcs->flags);
- err = validate_change(cs, &trialcs);
+ err = validate_change(cs, trialcs);
if (err < 0)
- return err;
+ goto out;
+
+ err = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL);
+ if (err < 0)
+ goto out;
- cpus_nonempty = !cpus_empty(trialcs.cpus_allowed);
balance_flag_changed = (is_sched_load_balance(cs) !=
- is_sched_load_balance(&trialcs));
+ 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;
+ cs->flags = trialcs->flags;
mutex_unlock(&callback_mutex);
- if (cpus_nonempty && balance_flag_changed)
- rebuild_sched_domains();
+ if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
+ async_rebuild_sched_domains();
- return 0;
+ if (spread_flag_changed)
+ update_tasks_flags(cs, &heap);
+ heap_free(&heap);
+out:
+ free_trial_cpuset(trialcs);
+ return err;
}
/*
}
/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
-static int cpuset_can_attach(struct cgroup_subsys *ss,
- struct cgroup *cont, struct task_struct *tsk)
+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))
+ if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
return -ENOSPC;
- if (tsk->flags & PF_THREAD_BOUND) {
- cpumask_t mask;
- mutex_lock(&callback_mutex);
- mask = cs->cpus_allowed;
- mutex_unlock(&callback_mutex);
- if (!cpus_equal(tsk->cpus_allowed, mask))
- return -EINVAL;
- }
+ /*
+ * Kthreads bound to specific cpus cannot be moved to a new cpuset; we
+ * cannot 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.
+ */
+ if (tsk->flags & PF_THREAD_BOUND)
+ return -EINVAL;
- return security_task_setscheduler(tsk, 0, NULL);
+ return 0;
}
-static void cpuset_attach(struct cgroup_subsys *ss,
- struct cgroup *cont, struct cgroup *oldcont,
- struct task_struct *tsk)
+static int cpuset_can_attach_task(struct cgroup *cgrp, struct task_struct *task)
+{
+ return security_task_setscheduler(task);
+}
+
+/*
+ * Protected by cgroup_lock. The nodemasks must be stored globally because
+ * dynamically allocating them is not allowed in pre_attach, and they must
+ * persist among pre_attach, attach_task, and attach.
+ */
+static cpumask_var_t cpus_attach;
+static nodemask_t cpuset_attach_nodemask_from;
+static nodemask_t cpuset_attach_nodemask_to;
+
+/* Set-up work for before attaching each task. */
+static void cpuset_pre_attach(struct cgroup *cont)
{
- cpumask_t cpus;
- nodemask_t from, to;
- struct mm_struct *mm;
struct cpuset *cs = cgroup_cs(cont);
- struct cpuset *oldcs = cgroup_cs(oldcont);
+
+ if (cs == &top_cpuset)
+ cpumask_copy(cpus_attach, cpu_possible_mask);
+ else
+ guarantee_online_cpus(cs, cpus_attach);
+
+ guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
+}
+
+/* Per-thread attachment work. */
+static void cpuset_attach_task(struct cgroup *cont, struct task_struct *tsk)
+{
int err;
+ struct cpuset *cs = cgroup_cs(cont);
- mutex_lock(&callback_mutex);
- guarantee_online_cpus(cs, &cpus);
- err = set_cpus_allowed_ptr(tsk, &cpus);
- mutex_unlock(&callback_mutex);
- if (err)
- return;
+ /*
+ * can_attach beforehand should guarantee that this doesn't fail.
+ * TODO: have a better way to handle failure here
+ */
+ err = set_cpus_allowed_ptr(tsk, cpus_attach);
+ WARN_ON_ONCE(err);
+
+ cpuset_change_task_nodemask(tsk, &cpuset_attach_nodemask_to);
+ cpuset_update_task_spread_flag(cs, tsk);
+}
+
+static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
+ struct cgroup *oldcont, struct task_struct *tsk)
+{
+ struct mm_struct *mm;
+ struct cpuset *cs = cgroup_cs(cont);
+ struct cpuset *oldcs = cgroup_cs(oldcont);
- from = oldcs->mems_allowed;
- to = cs->mems_allowed;
+ /*
+ * Change mm, possibly for multiple threads in a threadgroup. This is
+ * expensive and may sleep.
+ */
+ cpuset_attach_nodemask_from = oldcs->mems_allowed;
+ cpuset_attach_nodemask_to = cs->mems_allowed;
mm = get_task_mm(tsk);
if (mm) {
- mpol_rebind_mm(mm, &to);
+ mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
if (is_memory_migrate(cs))
- cpuset_migrate_mm(mm, &from, &to);
+ cpuset_migrate_mm(mm, &cpuset_attach_nodemask_from,
+ &cpuset_attach_nodemask_to);
mmput(mm);
}
-
}
/* The various types of files and directories in a cpuset file system */
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 */
- buffer = kmalloc(nbytes + 1, GFP_KERNEL);
- if (!buffer)
- 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;
- default:
- retval = -EINVAL;
- goto out2;
- }
-
- if (retval == 0)
- retval = nbytes;
-out2:
- cgroup_unlock();
-out1:
- kfree(buffer);
- return retval;
-}
-
static int cpuset_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
{
int retval = 0;
struct cpuset *cs = cgroup_cs(cgrp);
cpuset_filetype_t type = cft->private;
- cgroup_lock();
-
- if (cgroup_is_removed(cgrp)) {
- cgroup_unlock();
+ if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
- }
switch (type) {
case FILE_CPU_EXCLUSIVE:
break;
case FILE_SPREAD_PAGE:
retval = update_flag(CS_SPREAD_PAGE, cs, val);
- cs->mems_generation = cpuset_mems_generation++;
break;
case FILE_SPREAD_SLAB:
retval = update_flag(CS_SPREAD_SLAB, cs, val);
- cs->mems_generation = cpuset_mems_generation++;
break;
default:
retval = -EINVAL;
struct cpuset *cs = cgroup_cs(cgrp);
cpuset_filetype_t type = cft->private;
- cgroup_lock();
-
- if (cgroup_is_removed(cgrp)) {
- cgroup_unlock();
+ if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
- }
+
switch (type) {
case FILE_SCHED_RELAX_DOMAIN_LEVEL:
retval = update_relax_domain_level(cs, val);
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)
+{
+ int retval = 0;
+ struct cpuset *cs = cgroup_cs(cgrp);
+ struct cpuset *trialcs;
+
+ if (!cgroup_lock_live_group(cgrp))
+ return -ENODEV;
+
+ trialcs = alloc_trial_cpuset(cs);
+ if (!trialcs) {
+ retval = -ENOMEM;
+ goto out;
+ }
+
+ 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:
+ cgroup_unlock();
+ 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
* across a page fault.
*/
-static int cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
+static size_t cpuset_sprintf_cpulist(char *page, struct cpuset *cs)
{
- cpumask_t mask;
+ size_t count;
mutex_lock(&callback_mutex);
- mask = cs->cpus_allowed;
+ count = cpulist_scnprintf(page, PAGE_SIZE, cs->cpus_allowed);
mutex_unlock(&callback_mutex);
- return cpulist_scnprintf(page, PAGE_SIZE, mask);
+ return count;
}
-static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
+static size_t cpuset_sprintf_memlist(char *page, struct cpuset *cs)
{
- nodemask_t mask;
+ size_t count;
mutex_lock(&callback_mutex);
- mask = cs->mems_allowed;
+ count = nodelist_scnprintf(page, PAGE_SIZE, cs->mems_allowed);
mutex_unlock(&callback_mutex);
- return nodelist_scnprintf(page, PAGE_SIZE, mask);
+ return count;
}
static ssize_t cpuset_common_file_read(struct cgroup *cont,
default:
BUG();
}
+
+ /* Unreachable but makes gcc happy */
+ return 0;
}
static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
default:
BUG();
}
+
+ /* Unrechable but makes gcc happy */
+ return 0;
}
{
.name = "cpus",
.read = cpuset_common_file_read,
- .write = cpuset_common_file_write,
+ .write_string = cpuset_write_resmask,
+ .max_write_len = (100U + 6 * NR_CPUS),
.private = FILE_CPULIST,
},
{
.name = "mems",
.read = cpuset_common_file_read,
- .write = cpuset_common_file_write,
+ .write_string = cpuset_write_resmask,
+ .max_write_len = (100U + 6 * MAX_NUMNODES),
.private = FILE_MEMLIST,
},
.read_u64 = cpuset_read_u64,
.write_u64 = cpuset_write_u64,
.private = FILE_MEMORY_PRESSURE,
+ .mode = S_IRUGO,
},
{
}
/*
- * 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'.
+ * post_clone() is called during cgroup_create() when the
+ * clone_children mount argument was specified. The cgroup
+ * can not yet have any tasks.
*
* Currently we refuse to set up the cgroup - thereby
* refusing the task to be entered, and as a result refusing
cs = cgroup_cs(cgroup);
parent_cs = cgroup_cs(parent);
+ mutex_lock(&callback_mutex);
cs->mems_allowed = parent_cs->mems_allowed;
- cs->cpus_allowed = parent_cs->cpus_allowed;
+ cpumask_copy(cs->cpus_allowed, parent_cs->cpus_allowed);
+ mutex_unlock(&callback_mutex);
return;
}
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);
+ if (!alloc_cpumask_var(&cs->cpus_allowed, GFP_KERNEL)) {
+ kfree(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);
- cpus_clear(cs->cpus_allowed);
+ cpumask_clear(cs->cpus_allowed);
nodes_clear(cs->mems_allowed);
- cs->mems_generation = cpuset_mems_generation++;
fmeter_init(&cs->fmeter);
cs->relax_domain_level = -1;
}
/*
- * 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 get_online_cpus()
- * call in rebuild_sched_domains() must not be made while holding
- * callback_mutex. Elsewhere the kernel nests callback_mutex inside
- * get_online_cpus() calls. So the reverse nesting would risk an
- * ABBA deadlock.
+ * will call async_rebuild_sched_domains().
*/
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--;
+ free_cpumask_var(cs->cpus_allowed);
kfree(cs);
}
struct cgroup_subsys cpuset_subsys = {
.name = "cpuset",
.create = cpuset_create,
- .destroy = cpuset_destroy,
+ .destroy = cpuset_destroy,
.can_attach = cpuset_can_attach,
+ .can_attach_task = cpuset_can_attach_task,
+ .pre_attach = cpuset_pre_attach,
+ .attach_task = cpuset_attach_task,
.attach = cpuset_attach,
.populate = cpuset_populate,
.post_clone = cpuset_post_clone,
.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
*
{
int err = 0;
- cpus_setall(top_cpuset.cpus_allowed);
+ 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);
- top_cpuset.mems_generation = cpuset_mems_generation++;
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
top_cpuset.relax_domain_level = -1;
if (err < 0)
return err;
+ if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL))
+ BUG();
+
number_of_cpusets = 1;
return 0;
}
static void cpuset_do_move_task(struct task_struct *tsk,
struct cgroup_scanner *scan)
{
- struct cpuset_hotplug_scanner *chsp;
+ struct cgroup *new_cgroup = scan->data;
- chsp = container_of(scan, struct cpuset_hotplug_scanner, scan);
- cgroup_attach_task(chsp->to, tsk);
+ cgroup_attach_task(new_cgroup, tsk);
}
/**
*/
static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
{
- struct cpuset_hotplug_scanner scan;
+ struct cgroup_scanner scan;
- scan.scan.cg = from->css.cgroup;
- scan.scan.test_task = NULL; /* select all tasks in cgroup */
- scan.scan.process_task = cpuset_do_move_task;
- scan.scan.heap = NULL;
- scan.to = to->css.cgroup;
+ scan.cg = from->css.cgroup;
+ scan.test_task = NULL; /* select all tasks in cgroup */
+ scan.process_task = cpuset_do_move_task;
+ scan.heap = NULL;
+ scan.data = to->css.cgroup;
- if (cgroup_scan_tasks((struct cgroup_scanner *)&scan))
+ if (cgroup_scan_tasks(&scan))
printk(KERN_ERR "move_member_tasks_to_cpuset: "
"cgroup_scan_tasks failed\n");
}
/*
- * If common_cpu_mem_hotplug_unplug(), below, unplugs any CPUs
+ * 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
* has online cpus, so can't be empty).
*/
parent = cs->parent;
- while (cpus_empty(parent->cpus_allowed) ||
+ while (cpumask_empty(parent->cpus_allowed) ||
nodes_empty(parent->mems_allowed))
parent = parent->parent;
* that has tasks along with an empty 'mems'. But if we did see such
* a cpuset, we'd handle it just like we do if its 'cpus' was empty.
*/
-static void scan_for_empty_cpusets(const struct cpuset *root)
+static void scan_for_empty_cpusets(struct cpuset *root)
{
+ LIST_HEAD(queue);
struct cpuset *cp; /* scans cpusets being updated */
struct cpuset *child; /* scans child cpusets of cp */
- struct list_head queue;
struct cgroup *cont;
-
- INIT_LIST_HEAD(&queue);
+ static nodemask_t oldmems; /* protected by cgroup_mutex */
list_add_tail((struct list_head *)&root->stack_list, &queue);
while (!list_empty(&queue)) {
- cp = container_of(queue.next, struct cpuset, stack_list);
+ cp = list_first_entry(&queue, struct cpuset, stack_list);
list_del(queue.next);
list_for_each_entry(cont, &cp->css.cgroup->children, sibling) {
child = cgroup_cs(cont);
list_add_tail(&child->stack_list, &queue);
}
- cont = cp->css.cgroup;
/* Continue past cpusets with all cpus, mems online */
- if (cpus_subset(cp->cpus_allowed, cpu_online_map) &&
+ if (cpumask_subset(cp->cpus_allowed, cpu_active_mask) &&
nodes_subset(cp->mems_allowed, node_states[N_HIGH_MEMORY]))
continue;
+ oldmems = cp->mems_allowed;
+
/* Remove offline cpus and mems from this cpuset. */
mutex_lock(&callback_mutex);
- cpus_and(cp->cpus_allowed, cp->cpus_allowed, cpu_online_map);
+ cpumask_and(cp->cpus_allowed, cp->cpus_allowed,
+ cpu_active_mask);
nodes_and(cp->mems_allowed, cp->mems_allowed,
node_states[N_HIGH_MEMORY]);
mutex_unlock(&callback_mutex);
/* Move tasks from the empty cpuset to a parent */
- if (cpus_empty(cp->cpus_allowed) ||
+ if (cpumask_empty(cp->cpus_allowed) ||
nodes_empty(cp->mems_allowed))
remove_tasks_in_empty_cpuset(cp);
+ else {
+ update_tasks_cpumask(cp, NULL);
+ update_tasks_nodemask(cp, &oldmems, NULL);
+ }
}
}
-/*
- * 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.
- *
- * 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(int rebuild_sd)
-{
- cgroup_lock();
-
- top_cpuset.cpus_allowed = cpu_online_map;
- top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
- scan_for_empty_cpusets(&top_cpuset);
-
- /*
- * Scheduler destroys domains on hotplug events.
- * Rebuild them based on the current settings.
- */
- if (rebuild_sd)
- rebuild_sched_domains();
-
- cgroup_unlock();
-}
-
/*
* The top_cpuset tracks what CPUs and Memory Nodes are online,
* period. This is necessary in order to make cpusets transparent
* 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.
+ * cpu_active_mask on each CPU hotplug (cpuhp) event.
+ *
+ * Called within get_online_cpus(). Needs to call cgroup_lock()
+ * before calling generate_sched_domains().
*/
+void cpuset_update_active_cpus(void)
+{
+ struct sched_domain_attr *attr;
+ cpumask_var_t *doms;
+ int ndoms;
-static int cpuset_handle_cpuhp(struct notifier_block *unused_nb,
- unsigned long phase, void *unused_cpu)
-{
- switch (phase) {
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- common_cpu_mem_hotplug_unplug(1);
- break;
- default:
- return NOTIFY_DONE;
- }
+ cgroup_lock();
+ mutex_lock(&callback_mutex);
+ cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
+ mutex_unlock(&callback_mutex);
+ scan_for_empty_cpusets(&top_cpuset);
+ ndoms = generate_sched_domains(&doms, &attr);
+ cgroup_unlock();
- return NOTIFY_OK;
+ /* Have scheduler rebuild the domains */
+ partition_sched_domains(ndoms, doms, attr);
}
#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().
+ * Call this routine anytime after node_states[N_HIGH_MEMORY] changes.
+ * See also the previous routine cpuset_track_online_cpus().
*/
-
-void cpuset_track_online_nodes(void)
+static int cpuset_track_online_nodes(struct notifier_block *self,
+ unsigned long action, void *arg)
{
- common_cpu_mem_hotplug_unplug(0);
+ static nodemask_t oldmems; /* protected by cgroup_mutex */
+
+ cgroup_lock();
+ switch (action) {
+ case MEM_ONLINE:
+ oldmems = top_cpuset.mems_allowed;
+ mutex_lock(&callback_mutex);
+ top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
+ mutex_unlock(&callback_mutex);
+ update_tasks_nodemask(&top_cpuset, &oldmems, NULL);
+ break;
+ case MEM_OFFLINE:
+ /*
+ * needn't update top_cpuset.mems_allowed explicitly because
+ * scan_for_empty_cpusets() will update it.
+ */
+ scan_for_empty_cpusets(&top_cpuset);
+ break;
+ default:
+ break;
+ }
+ cgroup_unlock();
+
+ return NOTIFY_OK;
}
#endif
void __init cpuset_init_smp(void)
{
- top_cpuset.cpus_allowed = cpu_online_map;
+ cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
- hotcpu_notifier(cpuset_handle_cpuhp, 0);
+ hotplug_memory_notifier(cpuset_track_online_nodes, 10);
+
+ cpuset_wq = create_singlethread_workqueue("cpuset");
+ BUG_ON(!cpuset_wq);
}
/**
-
* 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 cpumask_t variable to receive cpus_allowed set.
+ * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
*
- * Description: Returns the cpumask_t cpus_allowed of the cpuset
+ * 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_map, even if this means going outside the
* tasks cpuset.
**/
-void cpuset_cpus_allowed(struct task_struct *tsk, cpumask_t *pmask)
+void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
{
mutex_lock(&callback_mutex);
- cpuset_cpus_allowed_locked(tsk, pmask);
+ task_lock(tsk);
+ guarantee_online_cpus(task_cs(tsk), pmask);
+ task_unlock(tsk);
mutex_unlock(&callback_mutex);
}
-/**
- * cpuset_cpus_allowed_locked - return cpus_allowed mask from a tasks cpuset.
- * Must be called with callback_mutex held.
- **/
-void cpuset_cpus_allowed_locked(struct task_struct *tsk, cpumask_t *pmask)
+int cpuset_cpus_allowed_fallback(struct task_struct *tsk)
{
- task_lock(tsk);
- guarantee_online_cpus(task_cs(tsk), pmask);
- task_unlock(tsk);
+ const struct cpuset *cs;
+ int cpu;
+
+ rcu_read_lock();
+ cs = task_cs(tsk);
+ if (cs)
+ do_set_cpus_allowed(tsk, 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.
+ */
+
+ cpu = cpumask_any_and(&tsk->cpus_allowed, cpu_active_mask);
+ if (cpu >= nr_cpu_ids) {
+ /*
+ * Either tsk->cpus_allowed is wrong (see above) or it
+ * is actually empty. The latter case is only possible
+ * if we are racing with remove_tasks_in_empty_cpuset().
+ * Like above we can temporary set any mask and rely on
+ * set_cpus_allowed_ptr() as synchronization point.
+ */
+ do_set_cpus_allowed(tsk, cpu_possible_mask);
+ cpu = cpumask_any(cpu_active_mask);
+ }
+
+ return cpu;
}
void cpuset_init_current_mems_allowed(void)
}
/**
- * cpuset_zone_allowed_softwall - Can we allocate on zone z's memory node?
- * @z: is this zone on an allowed node?
+ * 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 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
- * hardwalled 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.
+ * 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_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.
+ * 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_zone_allowed_hardwall() only handles the simpler case of
- * hardwall cpusets, and never sleeps.
+ * 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
* 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
+ * 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_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
+int __cpuset_node_allowed_softwall(int node, 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;
}
/*
- * cpuset_zone_allowed_hardwall - Can we allocate on zone z's memory node?
- * @z: is this zone on an allowed node?
+ * 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 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.
+ * 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
* 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
+ * 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_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
+int __cpuset_node_allowed_hardwall(int node, 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;
/*
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
*
}
/**
- * cpuset_mem_spread_node() - On which node to begin search for a page
+ * 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),
* See kmem_cache_alloc_node().
*/
-int cpuset_mem_spread_node(void)
+static int cpuset_spread_node(int *rotor)
{
int node;
- node = next_node(current->cpuset_mem_spread_rotor, current->mems_allowed);
+ node = next_node(*rotor, current->mems_allowed);
if (node == MAX_NUMNODES)
node = first_node(current->mems_allowed);
- current->cpuset_mem_spread_rotor = node;
+ *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);
/**
return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
}
+/**
+ * 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)
+{
+ struct dentry *dentry;
+
+ dentry = task_cs(tsk)->css.cgroup->dentry;
+ spin_lock(&cpuset_buffer_lock);
+ snprintf(cpuset_name, CPUSET_NAME_LEN,
+ dentry ? (const char *)dentry->d_name.name : "/");
+ nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
+ tsk->mems_allowed);
+ printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n",
+ tsk->comm, cpuset_name, cpuset_nodelist);
+ spin_unlock(&cpuset_buffer_lock);
+}
+
/*
* Collection of memory_pressure is suppressed unless
* this flag is enabled by writing "1" to the special
};
#endif /* CONFIG_PROC_PID_CPUSET */
-/* Display task
cpus_allowed, mems_allowed in /proc/<pid>/status file. */
+/* 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, "Cpus_allowed:\t");
- m->count += cpumask_scnprintf(m->buf + m->count, m->size - m->count,
- task->cpus_allowed);
- seq_printf(m, "\n");
- seq_printf(m, "Cpus_allowed_list:\t");
- m->count += cpulist_scnprintf(m->buf + m->count, m->size - m->count,
- task->cpus_allowed);
- seq_printf(m, "\n");
seq_printf(m, "Mems_allowed:\t");
- m->count += nodemask_scnprintf(m->buf + m->count, m->size - m->count,
- task->mems_allowed);
+ seq_nodemask(m, &task->mems_allowed);
seq_printf(m, "\n");
seq_printf(m, "Mems_allowed_list:\t");
- m->count += nodelist_scnprintf(m->buf + m->count, m->size - m->count,
- task->mems_allowed);
+ seq_nodemask_list(m, &task->mems_allowed);
seq_printf(m, "\n");
}
Code Review / linux-2.6.git / blobdiff