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android, lmk: Send SIGKILL before setting TIF_MEMDIE. 

It was observed that setting TIF_MEMDIE before sending SIGKILL at
oom_kill_process() allows memory reserves to be depleted by allocations
which are not needed for terminating the OOM victim.

This patch reverts commit 6bc2b856bb ("staging: android: lowmemorykiller:
set TIF_MEMDIE before send kill sig"), for oom_kill_process() was updated
to send SIGKILL before setting TIF_MEMDIE.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tetsuo Handa 2015-09-06 14:25:35 +09:00 committed by Greg Kroah-Hartman
parent 5cc95cd81b
commit 3a81fc20ea
1 changed files with 4 additions and 8 deletions
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12
drivers/staging/android/lowmemorykiller.c
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@ -157,26 +157,22 @@ static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
} }
if (selected) { if (selected) {
task_lock(selected); task_lock(selected);
if (!selected->mm) { send_sig(SIGKILL, selected, 0);
/* Already exited, cannot do mark_tsk_oom_victim() */
task_unlock(selected);
goto out;
}
/* /*
* FIXME: lowmemorykiller shouldn't abuse global OOM killer * FIXME: lowmemorykiller shouldn't abuse global OOM killer
* infrastructure. There is no real reason why the selected * infrastructure. There is no real reason why the selected
* task should have access to the memory reserves. * task should have access to the memory reserves.
*/ */
mark_oom_victim(selected); if (selected->mm)
mark_oom_victim(selected);
task_unlock(selected); task_unlock(selected);
lowmem_print(1, "send sigkill to %d (%s), adj %hd, size %d\n", lowmem_print(1, "send sigkill to %d (%s), adj %hd, size %d\n",
selected->pid, selected->comm, selected->pid, selected->comm,
selected_oom_score_adj, selected_tasksize); selected_oom_score_adj, selected_tasksize);
lowmem_deathpending_timeout = jiffies + HZ; lowmem_deathpending_timeout = jiffies + HZ;
send_sig(SIGKILL, selected, 0);
rem += selected_tasksize; rem += selected_tasksize;
} }
out:
lowmem_print(4, "lowmem_scan %lu, %x, return %lu\n", lowmem_print(4, "lowmem_scan %lu, %x, return %lu\n",
sc->nr_to_scan, sc->gfp_mask, rem); sc->nr_to_scan, sc->gfp_mask, rem);
rcu_read_unlock(); rcu_read_unlock();