[Devel] [PATCH rh7 6/6] oom: resurrect berserker mode
Vladimir Davydov
vdavydov at parallels.com
Fri Sep 11 02:54:32 PDT 2015
The logic behind the OOM berserker is the same as in PCS6: if processes
are killed by oom killer too often (< sysctl vm.oom_relaxation, 1 sec by
default), we increase "rage" (min -10, max 20) and kill 1 << "rage"
youngest worst processes if "rage" >= 0.
https://jira.sw.ru/browse/PSBM-17930
Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
---
include/linux/memcontrol.h | 20 +++++++
include/linux/oom.h | 3 +
kernel/sysctl.c | 7 +++
mm/memcontrol.c | 11 ----
mm/oom_kill.c | 140 +++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 170 insertions(+), 11 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 0c856425ab7a..76a7dc8192fb 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -78,6 +78,19 @@ extern void mem_cgroup_uncharge_cache_page(struct page *page);
bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
struct mem_cgroup *memcg);
+
+static inline
+bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
+ struct mem_cgroup *memcg)
+{
+ bool ret;
+
+ rcu_read_lock();
+ ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
+ rcu_read_unlock();
+ return ret;
+}
+
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg);
extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
@@ -286,6 +299,13 @@ static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm
return NULL;
}
+static inline
+bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
+ struct mem_cgroup *memcg)
+{
+ return true;
+}
+
static inline bool mm_match_cgroup(struct mm_struct *mm,
struct mem_cgroup *memcg)
{
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 4e12187663ed..445f6242ec9e 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -35,7 +35,9 @@ struct oom_context {
struct task_struct *owner;
struct task_struct *victim;
unsigned long oom_start;
+ unsigned long oom_end;
unsigned long overdraft;
+ int rage;
wait_queue_head_t waitq;
};
@@ -125,4 +127,5 @@ extern struct task_struct *find_lock_task_mm(struct task_struct *p);
extern int sysctl_oom_dump_tasks;
extern int sysctl_oom_kill_allocating_task;
extern int sysctl_panic_on_oom;
+extern int sysctl_oom_relaxation;
#endif /* _INCLUDE_LINUX_OOM_H */
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 976f48c09748..9c081e3f350f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1184,6 +1184,13 @@ static struct ctl_table vm_table[] = {
.proc_handler = proc_dointvec,
},
{
+ .procname = "oom_relaxation",
+ .data = &sysctl_oom_relaxation,
+ .maxlen = sizeof(sysctl_oom_relaxation),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_ms_jiffies,
+ },
+ {
.procname = "overcommit_ratio",
.data = &sysctl_overcommit_ratio,
.maxlen = sizeof(sysctl_overcommit_ratio),
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 41fb41b16664..2b87dbc5c0cd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1474,17 +1474,6 @@ bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
return css_is_ancestor(&memcg->css, &root_memcg->css);
}
-static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
- struct mem_cgroup *memcg)
-{
- bool ret;
-
- rcu_read_lock();
- ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
- rcu_read_unlock();
- return ret;
-}
-
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
{
int ret;
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 70679e19e81d..b291c7e04e7a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -42,13 +42,18 @@
int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
int sysctl_oom_dump_tasks;
+int sysctl_oom_relaxation = HZ;
static DEFINE_SPINLOCK(oom_context_lock);
#define OOM_TIMEOUT (5 * HZ)
+#define OOM_BASE_RAGE -10
+#define OOM_MAX_RAGE 20
+
#ifndef CONFIG_MEMCG
struct oom_context oom_ctx = {
+ .rage = OOM_BASE_RAGE,
.waitq = __WAIT_QUEUE_HEAD_INITIALIZER(oom_ctx.waitq),
};
#endif
@@ -58,6 +63,8 @@ void init_oom_context(struct oom_context *ctx)
ctx->owner = NULL;
ctx->victim = NULL;
ctx->oom_start = 0;
+ ctx->oom_end = 0;
+ ctx->rage = OOM_BASE_RAGE;
init_waitqueue_head(&ctx->waitq);
}
@@ -485,6 +492,7 @@ void mark_oom_victim(struct task_struct *tsk)
*/
void exit_oom_victim(void)
{
+ unsigned long now = jiffies;
struct mem_cgroup *iter;
struct oom_context *ctx;
@@ -499,6 +507,7 @@ void exit_oom_victim(void)
ctx = mem_cgroup_oom_context(iter);
if (ctx->victim == current) {
ctx->victim = NULL;
+ ctx->oom_end = now;
if (!ctx->owner)
wake_up_all(&ctx->waitq);
}
@@ -506,6 +515,134 @@ void exit_oom_victim(void)
spin_unlock(&oom_context_lock);
}
+static void oom_berserker(struct task_struct *victim, unsigned long totalpages,
+ struct mem_cgroup *root_memcg, nodemask_t *nodemask)
+{
+ static DEFINE_RATELIMIT_STATE(berserker_rs,
+ DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+ unsigned long now = jiffies;
+ struct mem_cgroup *memcg, *memcg_to_put = NULL, *target_memcg = NULL;
+ struct oom_context *ctx;
+ struct task_struct *p;
+ unsigned long victim_overdraft;
+ unsigned long victim_points;
+ int rage = -1;
+ int killed = 0;
+
+ victim_points = oom_badness(victim, root_memcg, nodemask, totalpages,
+ &victim_overdraft);
+
+ /*
+ * Get the victim cgroup.
+ */
+ p = find_lock_task_mm(victim);
+ if (p) {
+ memcg = try_get_mem_cgroup_from_mm(p->mm);
+ task_unlock(p);
+ /*
+ * The victim could have been moved to another cgroup
+ * since it was selected. If so, assume it belonged to
+ * root_memcg.
+ */
+ if (root_memcg &&
+ !mem_cgroup_same_or_subtree(root_memcg, memcg)) {
+ mem_cgroup_put(memcg);
+ memcg = root_memcg;
+ } else
+ memcg_to_put = memcg;
+ } else {
+ /*
+ * The victim has already freed its memory, so we can't
+ * get its score and hence should not start berserker,
+ * because the latter relies on it.
+ */
+ return;
+ }
+
+ /*
+ * Update berserker rage on each oom kill. Select oom context
+ * with the maximal positive rage if any.
+ */
+ spin_lock(&oom_context_lock);
+ while (1) {
+ ctx = mem_cgroup_oom_context(memcg);
+ if (time_after(now, ctx->oom_end + sysctl_oom_relaxation))
+ ctx->rage = OOM_BASE_RAGE;
+ else if (ctx->rage < OOM_MAX_RAGE)
+ ctx->rage++;
+ if (ctx->rage >= rage) {
+ target_memcg = memcg;
+ rage = ctx->rage;
+ }
+ if (memcg == root_memcg)
+ break;
+ memcg = parent_mem_cgroup(memcg);
+ /*
+ * Break the loop if there is no parent (i.e. we've just
+ * done with the root cgroup). Needed for the system
+ * wide oom case (root_memcg equals NULL).
+ */
+ if (!memcg)
+ break;
+ }
+ spin_unlock(&oom_context_lock);
+
+ if (rage < 0)
+ goto out;
+
+ /*
+ * So, we are in rage. Kill (1 << rage) youngest tasks that are
+ * as bad as the victim.
+ */
+ read_lock(&tasklist_lock);
+ list_for_each_entry_reverse(p, &init_task.tasks, tasks) {
+ unsigned long overdraft;
+ unsigned long points;
+
+ if (p == victim || !p->mm ||
+ fatal_signal_pending(p) || p->flags & PF_EXITING ||
+ oom_unkillable_task(p, target_memcg, nodemask))
+ continue;
+
+ points = oom_badness(p, target_memcg, nodemask, totalpages,
+ &overdraft);
+ if (overdraft < victim_overdraft)
+ continue;
+
+ /*
+ * Consider tasks as equally bad if their score values
+ * (basically mem+swap usage in pages) differ by less
+ * than 1/4th.
+ */
+ if (overdraft == victim_overdraft && points < victim_points &&
+ 4 * (victim_points - points) >= victim_points)
+ continue;
+
+ /* Normalize score for reporting */
+ points = points * 1000 / totalpages;
+
+ if (__ratelimit(&berserker_rs)) {
+ task_lock(p);
+ pr_err("Rage kill process %d (%s) score %lu\n",
+ task_pid_nr(p), p->comm, points);
+ task_unlock(p);
+ }
+
+ do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
+ mem_cgroup_note_oom_kill(target_memcg, p);
+
+ if (++killed >= 1 << rage)
+ break;
+ }
+ read_unlock(&tasklist_lock);
+
+ pr_err("OOM killer in rage %d: %d tasks killed\n", rage, killed);
+out:
+ if (memcg_to_put)
+ mem_cgroup_put(memcg_to_put);
+}
+
#define K(x) ((x) << (PAGE_SHIFT-10))
/*
* Must be called while holding a reference to p, which will be released upon
@@ -617,6 +754,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
}
rcu_read_unlock();
+ oom_berserker(victim, totalpages, memcg, nodemask);
+
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
mem_cgroup_note_oom_kill(memcg, victim);
put_task_struct(victim);
@@ -699,6 +838,7 @@ bool oom_trylock(struct mem_cgroup *memcg)
show_stack(p, NULL);
ctx->owner = ctx->victim = NULL;
+ ctx->oom_end = now;
wake_up_all(&ctx->waitq);
}
} while ((iter = mem_cgroup_iter(memcg, iter, NULL)));
--
2.1.4
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