diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 5d8ca6e02e396bd1eb5a00118ecf6141c43900ac..0710143723bce194e7b77d80ef4314adb5e9e1d6 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -366,6 +366,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
struct mem_cgroup *,
struct mem_cgroup_reclaim_cookie *);
void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
+int mem_cgroup_scan_tasks(struct mem_cgroup *,
+ int (*)(struct task_struct *, void *), void *);
static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
@@ -446,6 +448,8 @@ unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
void mem_cgroup_handle_over_high(void);
+unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg);
+
void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
struct task_struct *p);
@@ -639,6 +643,12 @@ static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
{
}
+static inline int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
+ int (*fn)(struct task_struct *, void *), void *arg)
+{
+ return 0;
+}
+
static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
return 0;
@@ -669,6 +679,11 @@ mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
return 0;
}
+static inline unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+
static inline void
mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 5bc0457ee3a88955f64b750a06858d45cb74b5da..17946e5121b622f8b296193f7561b45ac83548ef 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -34,23 +34,11 @@ struct oom_control {
* for display purposes.
*/
const int order;
-};
-/*
- * Types of limitations to the nodes from which allocations may occur
- */
-enum oom_constraint {
- CONSTRAINT_NONE,
- CONSTRAINT_CPUSET,
- CONSTRAINT_MEMORY_POLICY,
- CONSTRAINT_MEMCG,
-};
-
-enum oom_scan_t {
- OOM_SCAN_OK, /* scan thread and find its badness */
- OOM_SCAN_CONTINUE, /* do not consider thread for oom kill */
- OOM_SCAN_ABORT, /* abort the iteration and return */
- OOM_SCAN_SELECT, /* always select this thread first */
+ /* Used by oom implementation, do not set */
+ unsigned long totalpages;
+ struct task_struct *chosen;
+ unsigned long chosen_points;
};
extern struct mutex oom_lock;
@@ -70,30 +58,10 @@ static inline bool oom_task_origin(const struct task_struct *p)
return p->signal->oom_flag_origin;
}
-extern void mark_oom_victim(struct task_struct *tsk);
-
-#ifdef CONFIG_MMU
-extern void wake_oom_reaper(struct task_struct *tsk);
-#else
-static inline void wake_oom_reaper(struct task_struct *tsk)
-{
-}
-#endif
-
extern unsigned long oom_badness(struct task_struct *p,
struct mem_cgroup *memcg, const nodemask_t *nodemask,
unsigned long totalpages);
-extern void oom_kill_process(struct oom_control *oc, struct task_struct *p,
- unsigned int points, unsigned long totalpages,
- const char *message);
-
-extern void check_panic_on_oom(struct oom_control *oc,
- enum oom_constraint constraint);
-
-extern enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
- struct task_struct *task);
-
extern bool out_of_memory(struct oom_control *oc);
extern void exit_oom_victim(struct task_struct *tsk);
@@ -101,14 +69,11 @@ extern void exit_oom_victim(struct task_struct *tsk);
extern int register_oom_notifier(struct notifier_block *nb);
extern int unregister_oom_notifier(struct notifier_block *nb);
-extern bool oom_killer_disabled;
extern bool oom_killer_disable(void);
extern void oom_killer_enable(void);
extern struct task_struct *find_lock_task_mm(struct task_struct *p);
-bool task_will_free_mem(struct task_struct *task);
-
/* sysctls */
extern int sysctl_oom_dump_tasks;
extern int sysctl_oom_kill_allocating_task;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4be518d4e68ab437549693161c189c7caefe87ae..48747ef5b88f98abed96476430d285c6e405c81d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -920,6 +920,43 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
iter != NULL; \
iter = mem_cgroup_iter(NULL, iter, NULL))
+/**
+ * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
+ * @memcg: hierarchy root
+ * @fn: function to call for each task
+ * @arg: argument passed to @fn
+ *
+ * This function iterates over tasks attached to @memcg or to any of its
+ * descendants and calls @fn for each task. If @fn returns a non-zero
+ * value, the function breaks the iteration loop and returns the value.
+ * Otherwise, it will iterate over all tasks and return 0.
+ *
+ * This function must not be called for the root memory cgroup.
+ */
+int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
+ int (*fn)(struct task_struct *, void *), void *arg)
+{
+ struct mem_cgroup *iter;
+ int ret = 0;
+
+ BUG_ON(memcg == root_mem_cgroup);
+
+ for_each_mem_cgroup_tree(iter, memcg) {
+ struct css_task_iter it;
+ struct task_struct *task;
+
+ css_task_iter_start(&iter->css, &it);
+ while (!ret && (task = css_task_iter_next(&it)))
+ ret = fn(task, arg);
+ css_task_iter_end(&it);
+ if (ret) {
+ mem_cgroup_iter_break(memcg, iter);
+ break;
+ }
+ }
+ return ret;
+}
+
/**
* mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
* @page: the page
@@ -1178,7 +1215,7 @@ static int mem_cgroup_count_children(struct mem_cgroup *memcg)
/*
* Return the memory (and swap, if configured) limit for a memcg.
*/
-static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
+unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
{
unsigned long limit;
@@ -1205,79 +1242,12 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
.gfp_mask = gfp_mask,
.order = order,
};
- struct mem_cgroup *iter;
- unsigned long chosen_points = 0;
- unsigned long totalpages;
- unsigned int points = 0;
- struct task_struct *chosen = NULL;
+ bool ret;
mutex_lock(&oom_lock);
-
- /*
- * If current has a pending SIGKILL or is exiting, then automatically
- * select it. The goal is to allow it to allocate so that it may
- * quickly exit and free its memory.
- */
- if (task_will_free_mem(current)) {
- mark_oom_victim(current);
- wake_oom_reaper(current);
- goto unlock;
- }
-
- check_panic_on_oom(&oc, CONSTRAINT_MEMCG);
- totalpages = mem_cgroup_get_limit(memcg) ? : 1;
- for_each_mem_cgroup_tree(iter, memcg) {
- struct css_task_iter it;
- struct task_struct *task;
-
- css_task_iter_start(&iter->css, &it);
- while ((task = css_task_iter_next(&it))) {
- switch (oom_scan_process_thread(&oc, task)) {
- case OOM_SCAN_SELECT:
- if (chosen)
- put_task_struct(chosen);
- chosen = task;
- chosen_points = ULONG_MAX;
- get_task_struct(chosen);
- /* fall through */
- case OOM_SCAN_CONTINUE:
- continue;
- case OOM_SCAN_ABORT:
- css_task_iter_end(&it);
- mem_cgroup_iter_break(memcg, iter);
- if (chosen)
- put_task_struct(chosen);
- /* Set a dummy value to return "true". */
- chosen = (void *) 1;
- goto unlock;
- case OOM_SCAN_OK:
- break;
- };
- points = oom_badness(task, memcg, NULL, totalpages);
- if (!points || points < chosen_points)
- continue;
- /* Prefer thread group leaders for display purposes */
- if (points == chosen_points &&
- thread_group_leader(chosen))
- continue;
-
- if (chosen)
- put_task_struct(chosen);
- chosen = task;
- chosen_points = points;
- get_task_struct(chosen);
- }
- css_task_iter_end(&it);
- }
-
- if (chosen) {
- points = chosen_points * 1000 / totalpages;
- oom_kill_process(&oc, chosen, points, totalpages,
- "Memory cgroup out of memory");
- }
-unlock:
+ ret = out_of_memory(&oc);
mutex_unlock(&oom_lock);
- return chosen;
+ return ret;
}
#if MAX_NUMNODES > 1
@@ -1600,7 +1570,7 @@ bool mem_cgroup_oom_synchronize(bool handle)
if (!memcg)
return false;
- if (!handle || oom_killer_disabled)
+ if (!handle)
goto cleanup;
owait.memcg = memcg;
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index d53a9aa00977cbd0f81970e9e8a30b011cc73f31..ef175518f05f2d24df08e217354a56b17c8e1c08 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -132,6 +132,11 @@ static inline bool is_sysrq_oom(struct oom_control *oc)
return oc->order == -1;
}
+static inline bool is_memcg_oom(struct oom_control *oc)
+{
+ return oc->memcg != NULL;
+}
+
/* return true if the task is not adequate as candidate victim task. */
static bool oom_unkillable_task(struct task_struct *p,
struct mem_cgroup *memcg, const nodemask_t *nodemask)
@@ -213,12 +218,17 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
return points > 0 ? points : 1;
}
+enum oom_constraint {
+ CONSTRAINT_NONE,
+ CONSTRAINT_CPUSET,
+ CONSTRAINT_MEMORY_POLICY,
+ CONSTRAINT_MEMCG,
+};
+
/*
* Determine the type of allocation constraint.
*/
-#ifdef CONFIG_NUMA
-static enum oom_constraint constrained_alloc(struct oom_control *oc,
- unsigned long *totalpages)
+static enum oom_constraint constrained_alloc(struct oom_control *oc)
{
struct zone *zone;
struct zoneref *z;
@@ -226,8 +236,16 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
bool cpuset_limited = false;
int nid;
+ if (is_memcg_oom(oc)) {
+ oc->totalpages = mem_cgroup_get_limit(oc->memcg) ?: 1;
+ return CONSTRAINT_MEMCG;
+ }
+
/* Default to all available memory */
- *totalpages = totalram_pages + total_swap_pages;
+ oc->totalpages = totalram_pages + total_swap_pages;
+
+ if (!IS_ENABLED(CONFIG_NUMA))
+ return CONSTRAINT_NONE;
if (!oc->zonelist)
return CONSTRAINT_NONE;
@@ -246,9 +264,9 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
*/
if (oc->nodemask &&
!nodes_subset(node_states[N_MEMORY], *oc->nodemask)) {
- *totalpages = total_swap_pages;
+ oc->totalpages = total_swap_pages;
for_each_node_mask(nid, *oc->nodemask)
- *totalpages += node_spanned_pages(nid);
+ oc->totalpages += node_spanned_pages(nid);
return CONSTRAINT_MEMORY_POLICY;
}
@@ -259,27 +277,21 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
cpuset_limited = true;
if (cpuset_limited) {
- *totalpages = total_swap_pages;
+ oc->totalpages = total_swap_pages;
for_each_node_mask(nid, cpuset_current_mems_allowed)
- *totalpages += node_spanned_pages(nid);
+ oc->totalpages += node_spanned_pages(nid);
return CONSTRAINT_CPUSET;
}
return CONSTRAINT_NONE;
}
-#else
-static enum oom_constraint constrained_alloc(struct oom_control *oc,
- unsigned long *totalpages)
-{
- *totalpages = totalram_pages + total_swap_pages;
- return CONSTRAINT_NONE;
-}
-#endif
-enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
- struct task_struct *task)
+static int oom_evaluate_task(struct task_struct *task, void *arg)
{
+ struct oom_control *oc = arg;
+ unsigned long points;
+
if (oom_unkillable_task(task, NULL, oc->nodemask))
- return OOM_SCAN_CONTINUE;
+ goto next;
/*
* This task already has access to memory reserves and is being killed.
@@ -289,68 +301,67 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
*/
if (!is_sysrq_oom(oc) && atomic_read(&task->signal->oom_victims)) {
struct task_struct *p = find_lock_task_mm(task);
- enum oom_scan_t ret = OOM_SCAN_ABORT;
+ bool reaped = false;
if (p) {
- if (test_bit(MMF_OOM_REAPED, &p->mm->flags))
- ret = OOM_SCAN_CONTINUE;
+ reaped = test_bit(MMF_OOM_REAPED, &p->mm->flags);
task_unlock(p);
}
-
- return ret;
+ if (reaped)
+ goto next;
+ goto abort;
}
/*
* If task is allocating a lot of memory and has been marked to be
* killed first if it triggers an oom, then select it.
*/
- if (oom_task_origin(task))
- return OOM_SCAN_SELECT;
+ if (oom_task_origin(task)) {
+ points = ULONG_MAX;
+ goto select;
+ }
- return OOM_SCAN_OK;
+ points = oom_badness(task, NULL, oc->nodemask, oc->totalpages);
+ if (!points || points < oc->chosen_points)
+ goto next;
+
+ /* Prefer thread group leaders for display purposes */
+ if (points == oc->chosen_points && thread_group_leader(oc->chosen))
+ goto next;
+select:
+ if (oc->chosen)
+ put_task_struct(oc->chosen);
+ get_task_struct(task);
+ oc->chosen = task;
+ oc->chosen_points = points;
+next:
+ return 0;
+abort:
+ if (oc->chosen)
+ put_task_struct(oc->chosen);
+ oc->chosen = (void *)-1UL;
+ return 1;
}
/*
- * Simple selection loop. We chose the process with the highest
- * number of 'points'. Returns -1 on scan abort.
+ * Simple selection loop. We choose the process with the highest number of
+ * 'points'. In case scan was aborted, oc->chosen is set to -1.
*/
-static struct task_struct *select_bad_process(struct oom_control *oc,
- unsigned int *ppoints, unsigned long totalpages)
+static void select_bad_process(struct oom_control *oc)
{
- struct task_struct *p;
- struct task_struct *chosen = NULL;
- unsigned long chosen_points = 0;
-
- rcu_read_lock();
- for_each_process(p) {
- unsigned int points;
-
- switch (oom_scan_process_thread(oc, p)) {
- case OOM_SCAN_SELECT:
- chosen = p;
- chosen_points = ULONG_MAX;
- /* fall through */
- case OOM_SCAN_CONTINUE:
- continue;
- case OOM_SCAN_ABORT:
- rcu_read_unlock();
- return (struct task_struct *)(-1UL);
- case OOM_SCAN_OK:
- break;
- };
- points = oom_badness(p, NULL, oc->nodemask, totalpages);
- if (!points || points < chosen_points)
- continue;
+ if (is_memcg_oom(oc))
+ mem_cgroup_scan_tasks(oc->memcg, oom_evaluate_task, oc);
+ else {
+ struct task_struct *p;
- chosen = p;
- chosen_points = points;
+ rcu_read_lock();
+ for_each_process(p)
+ if (oom_evaluate_task(p, oc))
+ break;
+ rcu_read_unlock();
}
- if (chosen)
- get_task_struct(chosen);
- rcu_read_unlock();
- *ppoints = chosen_points * 1000 / totalpages;
- return chosen;
+ oc->chosen_points = oc->chosen_points * 1000 / oc->totalpages;
}
/**
@@ -419,7 +430,7 @@ static void dump_header(struct oom_control *oc, struct task_struct *p)
static atomic_t oom_victims = ATOMIC_INIT(0);
static DECLARE_WAIT_QUEUE_HEAD(oom_victims_wait);
-bool oom_killer_disabled __read_mostly;
+static bool oom_killer_disabled __read_mostly;
#define K(x) ((x) << (PAGE_SHIFT-10))
@@ -627,7 +638,7 @@ static int oom_reaper(void *unused)
return 0;
}
-void wake_oom_reaper(struct task_struct *tsk)
+static void wake_oom_reaper(struct task_struct *tsk)
{
if (!oom_reaper_th)
return;
@@ -656,7 +667,11 @@ static int __init oom_init(void)
return 0;
}
subsys_initcall(oom_init)
-#endif
+#else
+static inline void wake_oom_reaper(struct task_struct *tsk)
+{
+}
+#endif /* CONFIG_MMU */
/**
* mark_oom_victim - mark the given task as OOM victim
@@ -665,7 +680,7 @@ subsys_initcall(oom_init)
* Has to be called with oom_lock held and never after
* oom has been disabled already.
*/
-void mark_oom_victim(struct task_struct *tsk)
+static void mark_oom_victim(struct task_struct *tsk)
{
WARN_ON(oom_killer_disabled);
/* OOM killer might race with memcg OOM */
@@ -760,7 +775,7 @@ static inline bool __task_will_free_mem(struct task_struct *task)
* Caller has to make sure that task->mm is stable (hold task_lock or
* it operates on the current).
*/
-bool task_will_free_mem(struct task_struct *task)
+static bool task_will_free_mem(struct task_struct *task)
{
struct mm_struct *mm = task->mm;
struct task_struct *p;
@@ -806,14 +821,10 @@ bool task_will_free_mem(struct task_struct *task)
return ret;
}
-/*
- * Must be called while holding a reference to p, which will be released upon
- * returning.
- */
-void oom_kill_process(struct oom_control *oc, struct task_struct *p,
- unsigned int points, unsigned long totalpages,
- const char *message)
+static void oom_kill_process(struct oom_control *oc, const char *message)
{
+ struct task_struct *p = oc->chosen;
+ unsigned int points = oc->chosen_points;
struct task_struct *victim = p;
struct task_struct *child;
struct task_struct *t;
@@ -860,7 +871,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
* oom_badness() returns 0 if the thread is unkillable
*/
child_points = oom_badness(child,
- oc->memcg, oc->nodemask, totalpages);
+ oc->memcg, oc->nodemask, oc->totalpages);
if (child_points > victim_points) {
put_task_struct(victim);
victim = child;
@@ -942,7 +953,8 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
/*
* Determines whether the kernel must panic because of the panic_on_oom sysctl.
*/
-void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint)
+static void check_panic_on_oom(struct oom_control *oc,
+ enum oom_constraint constraint)
{
if (likely(!sysctl_panic_on_oom))
return;
@@ -988,19 +1000,18 @@ EXPORT_SYMBOL_GPL(unregister_oom_notifier);
*/
bool out_of_memory(struct oom_control *oc)
{
- struct task_struct *p;
- unsigned long totalpages;
unsigned long freed = 0;
- unsigned int uninitialized_var(points);
enum oom_constraint constraint = CONSTRAINT_NONE;
if (oom_killer_disabled)
return false;
- blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
- if (freed > 0)
- /* Got some memory back in the last second. */
- return true;
+ if (!is_memcg_oom(oc)) {
+ blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
+ if (freed > 0)
+ /* Got some memory back in the last second. */
+ return true;
+ }
/*
* If current has a pending SIGKILL or is exiting, then automatically
@@ -1024,37 +1035,38 @@ bool out_of_memory(struct oom_control *oc)
/*
* Check if there were limitations on the allocation (only relevant for
- * NUMA) that may require different handling.
+ * NUMA and memcg) that may require different handling.
*/
- constraint = constrained_alloc(oc, &totalpages);
+ constraint = constrained_alloc(oc);
if (constraint != CONSTRAINT_MEMORY_POLICY)
oc->nodemask = NULL;
check_panic_on_oom(oc, constraint);
- if (sysctl_oom_kill_allocating_task && current->mm &&
- !oom_unkillable_task(current, NULL, oc->nodemask) &&
+ if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task &&
+ current->mm && !oom_unkillable_task(current, NULL, oc->nodemask) &&
current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
get_task_struct(current);
- oom_kill_process(oc, current, 0, totalpages,
- "Out of memory (oom_kill_allocating_task)");
+ oc->chosen = current;
+ oom_kill_process(oc, "Out of memory (oom_kill_allocating_task)");
return true;
}
- p = select_bad_process(oc, &points, totalpages);
+ select_bad_process(oc);
/* Found nothing?!?! Either we hang forever, or we panic. */
- if (!p && !is_sysrq_oom(oc)) {
+ if (!oc->chosen && !is_sysrq_oom(oc) && !is_memcg_oom(oc)) {
dump_header(oc, NULL);
panic("Out of memory and no killable processes...\n");
}
- if (p && p != (void *)-1UL) {
- oom_kill_process(oc, p, points, totalpages, "Out of memory");
+ if (oc->chosen && oc->chosen != (void *)-1UL) {
+ oom_kill_process(oc, !is_memcg_oom(oc) ? "Out of memory" :
+ "Memory cgroup out of memory");
/*
* Give the killed process a good chance to exit before trying
* to allocate memory again.
*/
schedule_timeout_killable(1);
}
- return true;
+ return !!oc->chosen;
}
/*