#include <linux/workqueue.h>
#include <linux/xattr.h>
#include <linux/fs.h>
+#include <linux/percpu-refcount.h>
#ifdef CONFIG_CGROUPS
*/
struct cgroup *cgroup;
- /*
- * State maintained by the cgroup system to allow subsystems
- * to be "busy". Should be accessed via css_get(),
- * css_tryget() and css_put().
- */
-
- atomic_t refcnt;
+ /* reference count - access via css_[try]get() and css_put() */
+ struct percpu_ref refcnt;
unsigned long flags;
/* ID for this css, if possible */
CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */
};
-/* Caller must verify that the css is not for root cgroup */
-static inline void __css_get(struct cgroup_subsys_state *css, int count)
-{
- atomic_add(count, &css->refcnt);
-}
-
-/*
- * Call css_get() to hold a reference on the css; it can be used
- * for a reference obtained via:
- * - an existing ref-counted reference to the css
- * - task->cgroups for a locked task
+/**
+ * css_get - obtain a reference on the specified css
+ * @css: target css
+ *
+ * The caller must already have a reference.
*/
-
static inline void css_get(struct cgroup_subsys_state *css)
{
/* We don't need to reference count the root state */
if (!(css->flags & CSS_ROOT))
- __css_get(css, 1);
+ percpu_ref_get(&css->refcnt);
}
-/*
- * Call css_tryget() to take a reference on a css if your existing
- * (known-valid) reference isn't already ref-counted. Returns false if
- * the css has been destroyed.
+/**
+ * css_tryget - try to obtain a reference on the specified css
+ * @css: target css
+ *
+ * Obtain a reference on @css if it's alive. The caller naturally needs to
+ * ensure that @css is accessible but doesn't have to be holding a
+ * reference on it - IOW, RCU protected access is good enough for this
+ * function. Returns %true if a reference count was successfully obtained;
+ * %false otherwise.
*/
-
-extern bool __css_tryget(struct cgroup_subsys_state *css);
static inline bool css_tryget(struct cgroup_subsys_state *css)
{
if (css->flags & CSS_ROOT)
return true;
- return __css_tryget(css);
+ return percpu_ref_tryget(&css->refcnt);
}
-/*
- * css_put() should be called to release a reference taken by
- * css_get() or css_tryget()
+/**
+ * css_put - put a css reference
+ * @css: target css
+ *
+ * Put a reference obtained via css_get() and css_tryget().
*/
-
-extern void __css_put(struct cgroup_subsys_state *css);
static inline void css_put(struct cgroup_subsys_state *css)
{
if (!(css->flags & CSS_ROOT))
- __css_put(css);
+ percpu_ref_put(&css->refcnt);
}
/* bits in struct cgroup flags field */
enum {
/* Control Group is dead */
- CGRP_REMOVED,
+ CGRP_DEAD,
/*
* Control Group has previously had a child cgroup or a task,
* but no longer (only if CGRP_NOTIFY_ON_RELEASE is set)
struct cgroup {
unsigned long flags; /* "unsigned long" so bitops work */
- /*
- * count users of this cgroup. >0 means busy, but doesn't
- * necessarily indicate the number of tasks in the cgroup
- */
- atomic_t count;
-
int id; /* ida allocated in-hierarchy ID */
/*
struct cgroupfs_root *root;
/*
- * List of cg_cgroup_links pointing at css_sets with
- * tasks in this cgroup. Protected by css_set_lock
+ * List of cgrp_cset_links pointing at css_sets with tasks in this
+ * cgroup. Protected by css_set_lock.
*/
- struct list_head css_sets;
-
- struct list_head allcg_node; /* cgroupfs_root->allcg_list */
- struct list_head cft_q_node; /* used during cftype add/rm */
+ struct list_head cset_links;
/*
* Linked list running through all cgroups that can
struct list_head pidlists;
struct mutex pidlist_mutex;
- /* For RCU-protected deletion */
+ /* For css percpu_ref killing and RCU-protected deletion */
struct rcu_head rcu_head;
- struct work_struct free_work;
+ struct work_struct destroy_work;
+ atomic_t css_kill_cnt;
/* List of events which userspace want to receive */
struct list_head event_list;
*
* - Remount is disallowed.
*
- * - rename(2) is disallowed.
++ * - rename(2) is disallowed.
++ *
+ * - "tasks" is removed. Everything should be at process
+ * granularity. Use "cgroup.procs" instead.
+ *
+ * - "release_agent" and "notify_on_release" are removed.
+ * Replacement notification mechanism will be implemented.
+ *
+ * - cpuset: tasks will be kept in empty cpusets when hotplug happens
+ * and take masks of ancestors with non-empty cpus/mems, instead of
+ * being moved to an ancestor.
+ *
+ * - cpuset: a task can be moved into an empty cpuset, and again it
+ * takes masks of ancestors.
*
* - memcg: use_hierarchy is on by default and the cgroup file for
* the flag is not created.
- *
- * The followings are planned changes.
- *
- * - release_agent will be disallowed once replacement notification
- * mechanism is implemented.
*/
CGRP_ROOT_SANE_BEHAVIOR = (1 << 0),
CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */
CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */
+
+ /* mount options live below bit 16 */
+ CGRP_ROOT_OPTION_MASK = (1 << 16) - 1,
+
+ CGRP_ROOT_SUBSYS_BOUND = (1 << 16), /* subsystems finished binding */
};
/*
struct cgroupfs_root {
struct super_block *sb;
- /*
- * The bitmask of subsystems intended to be attached to this
- * hierarchy
- */
+ /* The bitmask of subsystems attached to this hierarchy */
unsigned long subsys_mask;
/* Unique id for this hierarchy. */
int hierarchy_id;
- /* The bitmask of subsystems currently attached to this hierarchy */
- unsigned long actual_subsys_mask;
-
/* A list running through the attached subsystems */
struct list_head subsys_list;
/* A list running through the active hierarchies */
struct list_head root_list;
- /* All cgroups on this root, cgroup_mutex protected */
- struct list_head allcg_list;
-
/* Hierarchy-specific flags */
unsigned long flags;
struct list_head tasks;
/*
- * List of cg_cgroup_link objects on link chains from
- * cgroups referenced from this css_set. Protected by
- * css_set_lock
+ * List of cgrp_cset_links pointing at cgroups referenced from this
+ * css_set. Protected by css_set_lock.
*/
- struct list_head cg_links;
+ struct list_head cgrp_links;
/*
* Set of subsystem states, one for each subsystem. This array
*/
/* cftype->flags */
-#define CFTYPE_ONLY_ON_ROOT (1U << 0) /* only create on root cg */
-#define CFTYPE_NOT_ON_ROOT (1U << 1) /* don't create on root cg */
-#define CFTYPE_INSANE (1U << 2) /* don't create if sane_behavior */
+enum {
+ CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cg */
+ CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cg */
+ CFTYPE_INSANE = (1 << 2), /* don't create if sane_behavior */
+};
#define MAX_CFTYPE_NAME 64
* entry. The key/value pairs (and their ordering) should not
* change between reboots.
*/
- int (*read_map)(struct cgroup *cont, struct cftype *cft,
+ int (*read_map)(struct cgroup *cgrp, struct cftype *cft,
struct cgroup_map_cb *cb);
/*
* read_seq_string() is used for outputting a simple sequence
* using seqfile.
*/
- int (*read_seq_string)(struct cgroup *cont, struct cftype *cft,
+ int (*read_seq_string)(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *m);
ssize_t (*write)(struct cgroup *cgrp, struct cftype *cft,
return cgrp->subsys[subsys_id];
}
-/*
- * function to get the cgroup_subsys_state which allows for extra
- * rcu_dereference_check() conditions, such as locks used during the
- * cgroup_subsys::attach() methods.
+/**
+ * task_css_set_check - obtain a task's css_set with extra access conditions
+ * @task: the task to obtain css_set for
+ * @__c: extra condition expression to be passed to rcu_dereference_check()
+ *
+ * A task's css_set is RCU protected, initialized and exited while holding
+ * task_lock(), and can only be modified while holding both cgroup_mutex
+ * and task_lock() while the task is alive. This macro verifies that the
+ * caller is inside proper critical section and returns @task's css_set.
+ *
+ * The caller can also specify additional allowed conditions via @__c, such
+ * as locks used during the cgroup_subsys::attach() methods.
*/
#ifdef CONFIG_PROVE_RCU
extern struct mutex cgroup_mutex;
-#define task_subsys_state_check(task, subsys_id, __c) \
- rcu_dereference_check((task)->cgroups->subsys[(subsys_id)], \
- lockdep_is_held(&(task)->alloc_lock) || \
- lockdep_is_held(&cgroup_mutex) || (__c))
+#define task_css_set_check(task, __c) \
+ rcu_dereference_check((task)->cgroups, \
+ lockdep_is_held(&(task)->alloc_lock) || \
+ lockdep_is_held(&cgroup_mutex) || (__c))
#else
-#define task_subsys_state_check(task, subsys_id, __c) \
- rcu_dereference((task)->cgroups->subsys[(subsys_id)])
+#define task_css_set_check(task, __c) \
+ rcu_dereference((task)->cgroups)
#endif
+/**
+ * task_subsys_state_check - obtain css for (task, subsys) w/ extra access conds
+ * @task: the target task
+ * @subsys_id: the target subsystem ID
+ * @__c: extra condition expression to be passed to rcu_dereference_check()
+ *
+ * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
+ * synchronization rules are the same as task_css_set_check().
+ */
+#define task_subsys_state_check(task, subsys_id, __c) \
+ task_css_set_check((task), (__c))->subsys[(subsys_id)]
+
+/**
+ * task_css_set - obtain a task's css_set
+ * @task: the task to obtain css_set for
+ *
+ * See task_css_set_check().
+ */
+static inline struct css_set *task_css_set(struct task_struct *task)
+{
+ return task_css_set_check(task, false);
+}
+
+/**
+ * task_subsys_state - obtain css for (task, subsys)
+ * @task: the target task
+ * @subsys_id: the target subsystem ID
+ *
+ * See task_subsys_state_check().
+ */
static inline struct cgroup_subsys_state *
task_subsys_state(struct task_struct *task, int subsys_id)
{
/* A cgroup_iter should be treated as an opaque object */
struct cgroup_iter {
- struct list_head *cg_link;
+ struct list_head *cset_link;
struct list_head *task;
};
/* Get id and depth of css */
unsigned short css_id(struct cgroup_subsys_state *css);
-unsigned short css_depth(struct cgroup_subsys_state *css);
struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id);
#else /* !CONFIG_CGROUPS */
#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.
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 */
/*
/* for custom sched domain */
int relax_domain_level;
-
- struct work_struct hotplug_work;
};
/* Retrieve the cpuset for a cgroup */
- static inline struct cpuset *cgroup_cs(struct cgroup *cont)
+ static inline struct cpuset *cgroup_cs(struct cgroup *cgrp)
{
- return container_of(cgroup_subsys_state(cont, cpuset_subsys_id),
+ return container_of(cgroup_subsys_state(cgrp, cpuset_subsys_id),
struct cpuset, css);
}
/*
* CPU / memory hotplug is handled asynchronously.
*/
- static struct workqueue_struct *cpuset_propagate_hotplug_wq;
-
static void cpuset_hotplug_workfn(struct work_struct *work);
- static void cpuset_propagate_hotplug_workfn(struct work_struct *work);
- static void schedule_cpuset_propagate_hotplug(struct cpuset *cs);
-
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
/*
* Return in pmask the portion of a cpusets's cpus_allowed that
* are online. If none are online, walk up the cpuset hierarchy
- * until we find one that does have some online cpus. If we get
- * all the way to the top and still haven't found any online cpus,
- * return cpu_online_mask. Or if passed a NULL cs from an exit'ing
- * task, return cpu_online_mask.
+ * 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 (cs && !cpumask_intersects(cs->cpus_allowed, cpu_online_mask))
+ while (!cpumask_intersects(cs->cpus_allowed, cpu_online_mask))
cs = parent_cs(cs);
- if (cs)
- cpumask_and(pmask, cs->cpus_allowed, cpu_online_mask);
- else
- cpumask_copy(pmask, cpu_online_mask);
- BUG_ON(!cpumask_intersects(pmask, cpu_online_mask));
+ 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. If we get all the way to the top and still haven't
- * found any online mems, return node_states[N_MEMORY].
+ * 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 (cs && !nodes_intersects(cs->mems_allowed,
- node_states[N_MEMORY]))
+ while (!nodes_intersects(cs->mems_allowed, node_states[N_MEMORY]))
cs = parent_cs(cs);
- if (cs)
- nodes_and(*pmask, cs->mems_allowed,
- node_states[N_MEMORY]);
- else
- *pmask = node_states[N_MEMORY];
- BUG_ON(!nodes_intersects(*pmask, node_states[N_MEMORY]));
+ nodes_and(*pmask, cs->mems_allowed, node_states[N_MEMORY]);
}
/*
static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
{
- struct cgroup *cont;
+ struct cgroup *cgrp;
struct cpuset *c, *par;
int ret;
/* Each of our child cpusets must be a subset of us */
ret = -EBUSY;
- cpuset_for_each_child(c, cont, cur)
+ cpuset_for_each_child(c, cgrp, cur)
if (!is_cpuset_subset(c, trial))
goto out;
* overlap
*/
ret = -EINVAL;
- cpuset_for_each_child(c, cont, par) {
+ 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))
*/
ret = -ENOSPC;
if ((cgroup_task_count(cur->css.cgroup) || cur->attach_in_progress) &&
- (cpumask_empty(trial->cpus_allowed) ||
+ (cpumask_empty(trial->cpus_allowed) &&
nodes_empty(trial->mems_allowed)))
goto out;
* 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
+ * 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.
* is a subset of one of these domains, while there are as
* many such domains as possible, each as small as possible.
* doms - Conversion of 'csa' to an array of cpumasks, for passing to
- * the kernel/sched.c routine partition_sched_domains() in a
+ * 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.)
mutex_unlock(&cpuset_mutex);
}
- /**
- * cpuset_test_cpumask - test a task's cpus_allowed versus its cpuset's
- * @tsk: task to test
- * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
+ /*
+ * effective_cpumask_cpuset - return nearest ancestor with non-empty cpus
+ * @cs: the cpuset in interest
*
- * Call with cpuset_mutex held. May take callback_mutex during call.
- * Called for each task in a cgroup by cgroup_scan_tasks().
- * Return nonzero if this tasks's cpus_allowed mask should be changed (in other
- * words, if its mask is not equal to its cpuset's mask).
+ * 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 int cpuset_test_cpumask(struct task_struct *tsk,
- struct cgroup_scanner *scan)
+ static struct cpuset *effective_nodemask_cpuset(struct cpuset *cs)
{
- return !cpumask_equal(&tsk->cpus_allowed,
- (cgroup_cs(scan->cg))->cpus_allowed);
+ while (nodes_empty(cs->mems_allowed))
+ cs = parent_cs(cs);
+ return cs;
}
/**
static void cpuset_change_cpumask(struct task_struct *tsk,
struct cgroup_scanner *scan)
{
- set_cpus_allowed_ptr(tsk, ((cgroup_cs(scan->cg))->cpus_allowed));
+ struct cpuset *cpus_cs;
+
+ cpus_cs = effective_cpumask_cpuset(cgroup_cs(scan->cg));
+ set_cpus_allowed_ptr(tsk, cpus_cs->cpus_allowed);
}
/**
struct cgroup_scanner scan;
scan.cg = cs->css.cgroup;
- scan.test_task = cpuset_test_cpumask;
+ 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
if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask))
return -EINVAL;
}
- retval = validate_change(cs, trialcs);
- if (retval < 0)
- return retval;
/* 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;
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.
- */
- update_tasks_cpumask(cs, &heap);
+ update_tasks_cpumask_hier(cs, true, &heap);
heap_free(&heap);
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);
- guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
+ mems_cs = effective_nodemask_cpuset(task_cs(tsk));
+ guarantee_online_mems(mems_cs, &tsk->mems_allowed);
}
/*
static void cpuset_change_nodemask(struct task_struct *p,
struct cgroup_scanner *scan)
{
+ struct cpuset *cs = cgroup_cs(scan->cg);
struct mm_struct *mm;
- struct cpuset *cs;
int migrate;
- const nodemask_t *oldmem = scan->data;
- static nodemask_t newmems; /* protected by cpuset_mutex */
+ nodemask_t *newmems = scan->data;
- cs = cgroup_cs(scan->cg);
- guarantee_online_mems(cs, &newmems);
-
- cpuset_change_task_nodemask(p, &newmems);
+ cpuset_change_task_nodemask(p, newmems);
mm = get_task_mm(p);
if (!mm)
mpol_rebind_mm(mm, &cs->mems_allowed);
if (migrate)
- cpuset_migrate_mm(mm, oldmem, &cs->mems_allowed);
+ cpuset_migrate_mm(mm, &cs->old_mems_allowed, newmems);
mmput(mm);
}
/**
* 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 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, const nodemask_t *oldmem,
- struct ptr_heap *heap)
+ 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 = (nodemask_t *)oldmem;
+ scan.data = &newmems;
/*
* The mpol_rebind_mm() call takes mmap_sem, which we couldn't
*/
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
static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
const char *buf)
{
- NODEMASK_ALLOC(nodemask_t, oldmem, GFP_KERNEL);
int retval;
struct ptr_heap heap;
- if (!oldmem)
- return -ENOMEM;
-
/*
* top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
* it's read-only
goto done;
}
}
- *oldmem = cs->mems_allowed;
- if (nodes_equal(*oldmem, trialcs->mems_allowed)) {
+
+ if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
retval = 0; /* Too easy - nothing to do */
goto done;
}
cs->mems_allowed = trialcs->mems_allowed;
mutex_unlock(&callback_mutex);
- update_tasks_nodemask(cs, oldmem, &heap);
+ update_tasks_nodemask_hier(cs, true, &heap);
heap_free(&heap);
done:
- NODEMASK_FREE(oldmem);
return retval;
}
mutex_lock(&cpuset_mutex);
+ /*
+ * We allow to move tasks into an empty cpuset if sane_behavior
+ * flag is set.
+ */
ret = -ENOSPC;
- if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
+ 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) {
static void cpuset_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
- /* static bufs protected by cpuset_mutex */
- static nodemask_t cpuset_attach_nodemask_from;
+ /* static buf protected by cpuset_mutex */
static nodemask_t cpuset_attach_nodemask_to;
struct mm_struct *mm;
struct task_struct *task;
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);
if (cs == &top_cpuset)
cpumask_copy(cpus_attach, cpu_possible_mask);
else
- guarantee_online_cpus(cs, cpus_attach);
+ guarantee_online_cpus(cpus_cs, cpus_attach);
- guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
+ guarantee_online_mems(mems_cs, &cpuset_attach_nodemask_to);
cgroup_taskset_for_each(task, cgrp, tset) {
/*
* 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(leader);
if (mm) {
+ struct cpuset *mems_oldcs = effective_nodemask_cpuset(oldcs);
+
mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
- if (is_memory_migrate(cs))
- cpuset_migrate_mm(mm, &cpuset_attach_nodemask_from,
+
+ /*
+ * 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->attach_in_progress--;
+ cs->old_mems_allowed = cpuset_attach_nodemask_to;
- /*
- * We may have raced with CPU/memory hotunplug. Trigger hotplug
- * propagation if @cs doesn't have any CPU or memory. It will move
- * the newly added tasks to the nearest parent which can execute.
- */
- if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
- schedule_cpuset_propagate_hotplug(cs);
+ cs->attach_in_progress--;
+ if (!cs->attach_in_progress)
+ wake_up(&cpuset_attach_wq);
mutex_unlock(&cpuset_mutex);
}
* 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.
- *
- * Flushing cpuset_hotplug_work is enough to synchronize against
- * hotplug hanlding; however, cpuset_attach() may schedule
- * propagation work directly. Flush the workqueue too.
*/
flush_work(&cpuset_hotplug_work);
- flush_workqueue(cpuset_propagate_hotplug_wq);
mutex_lock(&cpuset_mutex);
if (!is_cpuset_online(cs))
return count;
}
- static ssize_t cpuset_common_file_read(struct cgroup *cont,
+ 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(cont);
+ struct cpuset *cs = cgroup_cs(cgrp);
cpuset_filetype_t type = cft->private;
char *page;
ssize_t retval = 0;
return retval;
}
- static u64 cpuset_read_u64(struct cgroup *cont, struct cftype *cft)
+ static u64 cpuset_read_u64(struct cgroup *cgrp, struct cftype *cft)
{
- struct cpuset *cs = cgroup_cs(cont);
+ struct cpuset *cs = cgroup_cs(cgrp);
cpuset_filetype_t type = cft->private;
switch (type) {
case FILE_CPU_EXCLUSIVE:
return 0;
}
- static s64 cpuset_read_s64(struct cgroup *cont, struct cftype *cft)
+ static s64 cpuset_read_s64(struct cgroup *cgrp, struct cftype *cft)
{
- struct cpuset *cs = cgroup_cs(cont);
+ struct cpuset *cs = cgroup_cs(cgrp);
cpuset_filetype_t type = cft->private;
switch (type) {
case FILE_SCHED_RELAX_DOMAIN_LEVEL:
/*
* cpuset_css_alloc - allocate a cpuset css
- * cont: control group that the new cpuset will be part of
+ * cgrp: control group that the new cpuset will be part of
*/
- static struct cgroup_subsys_state *cpuset_css_alloc(struct cgroup *cont)
+ static struct cgroup_subsys_state *cpuset_css_alloc(struct cgroup *cgrp)
{
struct cpuset *cs;
- if (!cont->parent)
+ if (!cgrp->parent)
return &top_cpuset.css;
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
cpumask_clear(cs->cpus_allowed);
nodes_clear(cs->mems_allowed);
fmeter_init(&cs->fmeter);
- INIT_WORK(&cs->hotplug_work, cpuset_propagate_hotplug_workfn);
cs->relax_domain_level = -1;
return &cs->css;
* will call rebuild_sched_domains_locked().
*/
- static void cpuset_css_free(struct cgroup *cont)
+ static void cpuset_css_free(struct cgroup *cgrp)
{
- struct cpuset *cs = cgroup_cs(cont);
+ struct cpuset *cs = cgroup_cs(cgrp);
free_cpumask_var(cs->cpus_allowed);
kfree(cs);
}
/**
- * cpuset_propagate_hotplug_workfn - propagate CPU/memory hotplug to a cpuset
+ * 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_propagate_hotplug_workfn(struct work_struct *work)
+ static void cpuset_hotplug_update_tasks(struct cpuset *cs)
{
static cpumask_t off_cpus;
- static nodemask_t off_mems, tmp_mems;
- struct cpuset *cs = container_of(work, struct cpuset, hotplug_work);
+ 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);
- /* remove offline cpus from @cs */
- if (!cpumask_empty(&off_cpus)) {
- mutex_lock(&callback_mutex);
- cpumask_andnot(cs->cpus_allowed, cs->cpus_allowed, &off_cpus);
- mutex_unlock(&callback_mutex);
+ 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);
- }
- /* remove offline mems from @cs */
- if (!nodes_empty(off_mems)) {
- tmp_mems = cs->mems_allowed;
- mutex_lock(&callback_mutex);
- nodes_andnot(cs->mems_allowed, cs->mems_allowed, off_mems);
- mutex_unlock(&callback_mutex);
- update_tasks_nodemask(cs, &tmp_mems, 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 @cs became empty, move tasks to the nearest ancestor with
- * execution resources. This is full cgroup operation which will
+ * 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 (is_empty)
+ if (!sane && is_empty)
remove_tasks_in_empty_cpuset(cs);
-
- /* the following may free @cs, should be the last operation */
- css_put(&cs->css);
- }
-
- /**
- * schedule_cpuset_propagate_hotplug - schedule hotplug propagation to a cpuset
- * @cs: cpuset of interest
- *
- * Schedule cpuset_propagate_hotplug_workfn() which will update CPU and
- * memory masks according to top_cpuset.
- */
- static void schedule_cpuset_propagate_hotplug(struct cpuset *cs)
- {
- /*
- * Pin @cs. The refcnt will be released when the work item
- * finishes executing.
- */
- if (!css_tryget(&cs->css))
- return;
-
- /*
- * Queue @cs->hotplug_work. If already pending, lose the css ref.
- * cpuset_propagate_hotplug_wq is ordered and propagation will
- * happen in the order this function is called.
- */
- if (!queue_work(cpuset_propagate_hotplug_wq, &cs->hotplug_work))
- css_put(&cs->css);
}
/**
* 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_propagate_hotplug() is invoked on all
- * descendants.
+ * 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, tmp_cpus;
- static nodemask_t new_mems, tmp_mems;
+ static cpumask_t new_cpus;
+ static nodemask_t new_mems;
bool cpus_updated, mems_updated;
- bool cpus_offlined, mems_offlined;
mutex_lock(&cpuset_mutex);
new_mems = node_states[N_MEMORY];
cpus_updated = !cpumask_equal(top_cpuset.cpus_allowed, &new_cpus);
- cpus_offlined = cpumask_andnot(&tmp_cpus, top_cpuset.cpus_allowed,
- &new_cpus);
-
mems_updated = !nodes_equal(top_cpuset.mems_allowed, new_mems);
- nodes_andnot(tmp_mems, top_cpuset.mems_allowed, new_mems);
- mems_offlined = !nodes_empty(tmp_mems);
/* synchronize cpus_allowed to cpu_active_mask */
if (cpus_updated) {
/* synchronize mems_allowed to N_MEMORY */
if (mems_updated) {
- tmp_mems = top_cpuset.mems_allowed;
mutex_lock(&callback_mutex);
top_cpuset.mems_allowed = new_mems;
mutex_unlock(&callback_mutex);
- update_tasks_nodemask(&top_cpuset, &tmp_mems, NULL);
+ update_tasks_nodemask(&top_cpuset, NULL);
}
- /* if cpus or mems went down, we need to propagate to descendants */
- if (cpus_offlined || mems_offlined) {
+ 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)
- schedule_cpuset_propagate_hotplug(cs);
- rcu_read_unlock();
- }
+ cpuset_for_each_descendant_pre(cs, pos_cgrp, &top_cpuset) {
+ if (!css_tryget(&cs->css))
+ continue;
+ rcu_read_unlock();
- mutex_unlock(&cpuset_mutex);
+ cpuset_hotplug_update_tasks(cs);
- /* wait for propagations to finish */
- flush_workqueue(cpuset_propagate_hotplug_wq);
+ rcu_read_lock();
+ css_put(&cs->css);
+ }
+ rcu_read_unlock();
+ }
/* rebuild sched domains if cpus_allowed has changed */
if (cpus_updated)
{
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_propagate_hotplug_wq =
- alloc_ordered_workqueue("cpuset_hotplug", 0);
- BUG_ON(!cpuset_propagate_hotplug_wq);
}
/**
void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
{
+ struct cpuset *cpus_cs;
+
mutex_lock(&callback_mutex);
task_lock(tsk);
- guarantee_online_cpus(task_cs(tsk), pmask);
+ 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 *cs;
+ const struct cpuset *cpus_cs;
rcu_read_lock();
- cs = task_cs(tsk);
- if (cs)
- do_set_cpus_allowed(tsk, cs->cpus_allowed);
+ cpus_cs = effective_cpumask_cpuset(task_cs(tsk));
+ do_set_cpus_allowed(tsk, cpus_cs->cpus_allowed);
rcu_read_unlock();
/*
nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
{
+ struct cpuset *mems_cs;
nodemask_t mask;
mutex_lock(&callback_mutex);
task_lock(tsk);
- guarantee_online_mems(task_cs(tsk), &mask);
+ mems_cs = effective_nodemask_cpuset(task_cs(tsk));
+ guarantee_online_mems(mems_cs, &mask);
task_unlock(tsk);
mutex_unlock(&callback_mutex);
projects / linux.git / commitdiff