Due to commit 696453e66630ad45 ("mm, oom: task_will_free_mem should skip
oom_reaped tasks") and patch "mm,oom: Use ALLOC_OOM for OOM victim's last
second allocation.", thread groups sharing the OOM victim's mm without
setting ->signal->oom_mm before task_will_free_mem(current) is called
might fail to try ALLOC_OOM allocation attempt.
Therefore, make sure that all thread groups sharing the OOM victim's mm can
try ALLOC_OOM allocation attempt by calling mark_oom_victim() on all thread
groups sharing the OOM victim's mm, by calling oom_kill_process() even if
task_will_free_mem(current) is true.
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Fixes: 696453e66630ad45 ("mm, oom: task_will_free_mem should skip oom_reaped tasks")
---
mm/oom_kill.c | 49 ++++++++++++++++++++++++++-----------------------
1 file changed, 26 insertions(+), 23 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3b0d0fe..399ae36 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -826,6 +826,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
bool can_oom_reap = true;
+ bool verbose = false;
/*
* If the task is already exiting, don't alarm the sysadmin or kill
@@ -833,13 +834,8 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
* 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;
- }
+ if (task_will_free_mem(p))
+ goto mark_victims;
task_unlock(p);
if (__ratelimit(&oom_rs))
@@ -876,7 +872,9 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
}
read_unlock(&tasklist_lock);
+ verbose = true;
p = find_lock_task_mm(victim);
+ mark_victims:
if (!p) {
put_task_struct(victim);
return;
@@ -891,8 +889,10 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
mmgrab(mm);
/* Raise event before sending signal: task reaper must see this */
- count_vm_event(OOM_KILL);
- count_memcg_event_mm(mm, OOM_KILL);
+ if (verbose) {
+ count_vm_event(OOM_KILL);
+ count_memcg_event_mm(mm, OOM_KILL);
+ }
/*
* We should send SIGKILL before granting access to memory reserves
@@ -901,21 +901,18 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
*/
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
mark_oom_victim(victim);
- pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
- task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
- K(get_mm_counter(victim->mm, MM_ANONPAGES)),
- K(get_mm_counter(victim->mm, MM_FILEPAGES)),
- K(get_mm_counter(victim->mm, MM_SHMEMPAGES)));
+ if (verbose)
+ pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB, shmem-rss:%lukB\n",
+ task_pid_nr(victim), victim->comm, K(mm->total_vm),
+ K(get_mm_counter(mm, MM_ANONPAGES)),
+ K(get_mm_counter(mm, MM_FILEPAGES)),
+ K(get_mm_counter(mm, MM_SHMEMPAGES)));
task_unlock(victim);
/*
- * Kill all user processes sharing victim->mm in other thread groups, if
- * any. They don't get access to memory reserves, though, to avoid
- * depletion of all memory. This prevents mm->mmap_sem livelock when an
- * oom killed thread cannot exit because it requires the semaphore and
- * its contended by another thread trying to allocate memory itself.
- * That thread will now get access to memory reserves since it has a
- * pending fatal signal.
+ * Kill all user processes, if any, sharing victim->mm in other thread
+ * groups and grant access to memory reserves. This helps the OOM
+ * reaper to reclaim memory.
*/
rcu_read_lock();
for_each_process(p) {
@@ -938,6 +935,11 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
if (unlikely(p->flags & PF_KTHREAD))
continue;
do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
+ t = find_lock_task_mm(p);
+ if (!t)
+ continue;
+ mark_oom_victim(t);
+ task_unlock(t);
}
rcu_read_unlock();
@@ -1018,8 +1020,9 @@ bool out_of_memory(struct oom_control *oc)
* quickly exit and free its memory.
*/
if (task_will_free_mem(current)) {
- mark_oom_victim(current);
- wake_oom_reaper(current);
+ get_task_struct(current);
+ oc->chosen = current;
+ oom_kill_process(oc, "");
return true;
}
--
1.8.3.1
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