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authorShakeel Butt <shakeelb@google.com>2019-07-11 21:00:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-12 11:05:47 -0700
commit6ba749ee78ef42ffdf4b95c042fc574a37d229d9 (patch)
treecfe8087747269d44a79dbeecb6be94c82d9af034 /mm
parent5eee7e1cdb97123bb55ac14ccd3af8b6edc31537 (diff)
downloadlinux-6ba749ee78ef42ffdf4b95c042fc574a37d229d9.tar.bz2
mm, oom: remove redundant task_in_mem_cgroup() check
oom_unkillable_task() can be called from three different contexts i.e. global OOM, memcg OOM and oom_score procfs interface. At the moment oom_unkillable_task() does a task_in_mem_cgroup() check on the given process. Since there is no reason to perform task_in_mem_cgroup() check for global OOM and oom_score procfs interface, those contexts provide NULL memcg and skips the task_in_mem_cgroup() check. However for memcg OOM context, the oom_unkillable_task() is always called from mem_cgroup_scan_tasks() and thus task_in_mem_cgroup() check becomes redundant and effectively dead code. So, just remove the task_in_mem_cgroup() check altogether. Link: http://lkml.kernel.org/r/20190624212631.87212-2-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Jackson <pj@sgi.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> 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/memcontrol.c26
-rw-r--r--mm/oom_kill.c19
2 files changed, 7 insertions, 38 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 773ae5674e12..4f05735b02d3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1259,32 +1259,6 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
*lru_size += nr_pages;
}
-bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
-{
- struct mem_cgroup *task_memcg;
- struct task_struct *p;
- bool ret;
-
- p = find_lock_task_mm(task);
- if (p) {
- task_memcg = get_mem_cgroup_from_mm(p->mm);
- task_unlock(p);
- } else {
- /*
- * All threads may have already detached their mm's, but the oom
- * killer still needs to detect if they have already been oom
- * killed to prevent needlessly killing additional tasks.
- */
- rcu_read_lock();
- task_memcg = mem_cgroup_from_task(task);
- css_get(&task_memcg->css);
- rcu_read_unlock();
- }
- ret = mem_cgroup_is_descendant(task_memcg, memcg);
- css_put(&task_memcg->css);
- return ret;
-}
-
/**
* mem_cgroup_margin - calculate chargeable space of a memory cgroup
* @memcg: the memory cgroup
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 59326614508a..b353f468a36a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -153,17 +153,13 @@ static inline bool is_memcg_oom(struct oom_control *oc)
/* 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)
+ const nodemask_t *nodemask)
{
if (is_global_init(p))
return true;
if (p->flags & PF_KTHREAD)
return true;
- /* When mem_cgroup_out_of_memory() and p is not member of the group */
- if (memcg && !task_in_mem_cgroup(p, memcg))
- return true;
-
/* p may not have freeable memory in nodemask */
if (!has_intersects_mems_allowed(p, nodemask))
return true;
@@ -194,20 +190,19 @@ static bool is_dump_unreclaim_slabs(void)
* oom_badness - heuristic function to determine which candidate task to kill
* @p: task struct of which task we should calculate
* @totalpages: total present RAM allowed for page allocation
- * @memcg: task's memory controller, if constrained
* @nodemask: nodemask passed to page allocator for mempolicy ooms
*
* The heuristic for determining which task to kill is made to be as simple and
* predictable as possible. The goal is to return the highest value for the
* task consuming the most memory to avoid subsequent oom failures.
*/
-unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
+unsigned long oom_badness(struct task_struct *p,
const nodemask_t *nodemask, unsigned long totalpages)
{
long points;
long adj;
- if (oom_unkillable_task(p, memcg, nodemask))
+ if (oom_unkillable_task(p, nodemask))
return 0;
p = find_lock_task_mm(p);
@@ -318,7 +313,7 @@ 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))
+ if (oom_unkillable_task(task, oc->nodemask))
goto next;
/*
@@ -342,7 +337,7 @@ static int oom_evaluate_task(struct task_struct *task, void *arg)
goto select;
}
- points = oom_badness(task, NULL, oc->nodemask, oc->totalpages);
+ points = oom_badness(task, oc->nodemask, oc->totalpages);
if (!points || points < oc->chosen_points)
goto next;
@@ -387,7 +382,7 @@ static int dump_task(struct task_struct *p, void *arg)
struct oom_control *oc = arg;
struct task_struct *task;
- if (oom_unkillable_task(p, NULL, oc->nodemask))
+ if (oom_unkillable_task(p, oc->nodemask))
return 0;
task = find_lock_task_mm(p);
@@ -1084,7 +1079,7 @@ bool out_of_memory(struct oom_control *oc)
check_panic_on_oom(oc);
if (!is_memcg_oom(oc) && sysctl_oom_kill_allocating_task &&
- current->mm && !oom_unkillable_task(current, NULL, oc->nodemask) &&
+ current->mm && !oom_unkillable_task(current, oc->nodemask) &&
current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
get_task_struct(current);
oc->chosen = current;