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authorRoman Gushchin <guro@fb.com>2018-08-21 21:53:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 10:52:45 -0700
commit5989ad7b5ede38d605c588981f634c08252abfc3 (patch)
tree912ceb33925476039f9340bd1011575ab59a8809 /mm
parent1caed86022b9eb927283d8b2cdd7216baf43029e (diff)
downloadlinux-stericsson-5989ad7b5ede38d605c588981f634c08252abfc3.tar.gz
mm, oom: refactor oom_kill_process()
Patch series "introduce memory.oom.group", v2. This is a tiny implementation of cgroup-aware OOM killer, which adds an ability to kill a cgroup as a single unit and so guarantee the integrity of the workload. Although it has only a limited functionality in comparison to what now resides in the mm tree (it doesn't change the victim task selection algorithm, doesn't look at memory stas on cgroup level, etc), it's also much simpler and more straightforward. So, hopefully, we can avoid having long debates here, as we had with the full implementation. As it doesn't prevent any futher development, and implements an useful and complete feature, it looks as a sane way forward. This patch (of 2): oom_kill_process() consists of two logical parts: the first one is responsible for considering task's children as a potential victim and printing the debug information. The second half is responsible for sending SIGKILL to all tasks sharing the mm struct with the given victim. This commit splits oom_kill_process() with an intention to re-use the the second half: __oom_kill_process(). The cgroup-aware OOM killer will kill multiple tasks belonging to the victim cgroup. We don't need to print the debug information for the each task, as well as play with task selection (considering task's children), so we can't use the existing oom_kill_process(). Link: http://lkml.kernel.org/r/20171130152824.1591-2-guro@fb.com Link: http://lkml.kernel.org/r/20180802003201.817-3-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/oom_kill.c123
1 files changed, 65 insertions, 58 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 20600779f5db..330416c67ce5 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -829,68 +829,12 @@ static bool task_will_free_mem(struct task_struct *task)
return ret;
}
-static void oom_kill_process(struct oom_control *oc, const char *message)
+static void __oom_kill_process(struct task_struct *victim)
{
- 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;
+ struct task_struct *p;
struct mm_struct *mm;
- unsigned int victim_points = 0;
- static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
- DEFAULT_RATELIMIT_BURST);
bool can_oom_reap = true;
- /*
- * If the task is already exiting, don't alarm the sysadmin or kill
- * its children or threads, just give it access to memory reserves
- * so it can die quickly
- */
- task_lock(p);
- if (task_will_free_mem(p)) {
- mark_oom_victim(p);
- wake_oom_reaper(p);
- task_unlock(p);
- put_task_struct(p);
- return;
- }
- task_unlock(p);
-
- if (__ratelimit(&oom_rs))
- dump_header(oc, p);
-
- pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
- message, task_pid_nr(p), p->comm, points);
-
- /*
- * If any of p's children has a different mm and is eligible for kill,
- * the one with the highest oom_badness() score is sacrificed for its
- * parent. This attempts to lose the minimal amount of work done while
- * still freeing memory.
- */
- read_lock(&tasklist_lock);
- for_each_thread(p, t) {
- list_for_each_entry(child, &t->children, sibling) {
- unsigned int child_points;
-
- if (process_shares_mm(child, p->mm))
- continue;
- /*
- * oom_badness() returns 0 if the thread is unkillable
- */
- child_points = oom_badness(child,
- oc->memcg, oc->nodemask, oc->totalpages);
- if (child_points > victim_points) {
- put_task_struct(victim);
- victim = child;
- victim_points = child_points;
- get_task_struct(victim);
- }
- }
- }
- read_unlock(&tasklist_lock);
-
p = find_lock_task_mm(victim);
if (!p) {
put_task_struct(victim);
@@ -964,6 +908,69 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
}
#undef K
+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;
+ unsigned int victim_points = 0;
+ static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+ /*
+ * If the task is already exiting, don't alarm the sysadmin or kill
+ * its children or threads, just give it access to memory reserves
+ * so it can die quickly
+ */
+ task_lock(p);
+ if (task_will_free_mem(p)) {
+ mark_oom_victim(p);
+ wake_oom_reaper(p);
+ task_unlock(p);
+ put_task_struct(p);
+ return;
+ }
+ task_unlock(p);
+
+ if (__ratelimit(&oom_rs))
+ dump_header(oc, p);
+
+ pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
+ message, task_pid_nr(p), p->comm, points);
+
+ /*
+ * If any of p's children has a different mm and is eligible for kill,
+ * the one with the highest oom_badness() score is sacrificed for its
+ * parent. This attempts to lose the minimal amount of work done while
+ * still freeing memory.
+ */
+ read_lock(&tasklist_lock);
+ for_each_thread(p, t) {
+ list_for_each_entry(child, &t->children, sibling) {
+ unsigned int child_points;
+
+ if (process_shares_mm(child, p->mm))
+ continue;
+ /*
+ * oom_badness() returns 0 if the thread is unkillable
+ */
+ child_points = oom_badness(child,
+ oc->memcg, oc->nodemask, oc->totalpages);
+ if (child_points > victim_points) {
+ put_task_struct(victim);
+ victim = child;
+ victim_points = child_points;
+ get_task_struct(victim);
+ }
+ }
+ }
+ read_unlock(&tasklist_lock);
+
+ __oom_kill_process(victim);
+}
+
/*
* Determines whether the kernel must panic because of the panic_on_oom sysctl.
*/