The patch titled
oom-kill: remove boost_dying_task_prio()
has been added to the -mm tree. Its filename is
oom-kill-remove-boost_dying_task_prio.patch
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------------------------------------------------------
Subject: oom-kill: remove boost_dying_task_prio()
From: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
This is an almost-revert of commit 93b43fa ("oom: give the dying task a
higher priority").
That commit dramatically improved oom killer logic when a fork-bomb
occurs. But I've found that it has nasty corner case. Now cpu cgroup has
strange default RT runtime. It's 0! That said, if a process under cpu
cgroup promote RT scheduling class, the process never run at all.
Eventually, kernel may hang up when oom kill occur. I and Luis who
original author agreed to disable this logic at once.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Acked-by: Luis Claudio R. Goncalves <lclaudio@xxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 28 ----------------------------
1 file changed, 28 deletions(-)
diff -puN mm/oom_kill.c~oom-kill-remove-boost_dying_task_prio mm/oom_kill.c
--- a/mm/oom_kill.c~oom-kill-remove-boost_dying_task_prio
+++ a/mm/oom_kill.c
@@ -84,24 +84,6 @@ static bool has_intersects_mems_allowed(
#endif /* CONFIG_NUMA */
/*
- * If this is a system OOM (not a memcg OOM) and the task selected to be
- * killed is not already running at high (RT) priorities, speed up the
- * recovery by boosting the dying task to the lowest FIFO priority.
- * That helps with the recovery and avoids interfering with RT tasks.
- */
-static void boost_dying_task_prio(struct task_struct *p,
- struct mem_cgroup *mem)
-{
- struct sched_param param = { .sched_priority = 1 };
-
- if (mem)
- return;
-
- if (!rt_task(p))
- sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m);
-}
-
-/*
* The process p may have detached its own ->mm while exiting or through
* use_mm(), but one or more of its subthreads may still have a valid
* pointer. Return p, or any of its subthreads with a valid ->mm, with
@@ -452,13 +434,6 @@ static int oom_kill_task(struct task_str
set_tsk_thread_flag(p, TIF_MEMDIE);
force_sig(SIGKILL, p);
- /*
- * We give our sacrificial lamb high priority and access to
- * all the memory it needs. That way it should be able to
- * exit() and clear out its resources quickly...
- */
- boost_dying_task_prio(p, mem);
-
return 0;
}
#undef K
@@ -482,7 +457,6 @@ static int oom_kill_process(struct task_
*/
if (p->flags & PF_EXITING) {
set_tsk_thread_flag(p, TIF_MEMDIE);
- boost_dying_task_prio(p, mem);
return 0;
}
@@ -556,7 +530,6 @@ void mem_cgroup_out_of_memory(struct mem
*/
if (fatal_signal_pending(current)) {
set_thread_flag(TIF_MEMDIE);
- boost_dying_task_prio(current, NULL);
return;
}
@@ -712,7 +685,6 @@ void out_of_memory(struct zonelist *zone
*/
if (fatal_signal_pending(current)) {
set_thread_flag(TIF_MEMDIE);
- boost_dying_task_prio(current, NULL);
return;
}
_
Patches currently in -mm which might be from kosaki.motohiro@xxxxxxxxxxxxxx are
memcg-fix-mem_cgroup_rotate_reclaimable_page.patch
mm-per-node-vmstat-show-proper-vmstats.patch
mm-per-node-vmstat-show-proper-vmstats-fix.patch
mm-increase-reclaim_distance-to-30.patch
vmscan-all_unreclaimable-use-zone-all_unreclaimable-as-a-name.patch
oom-kill-remove-boost_dying_task_prio.patch
mm-introduce-wait_on_page_locked_killable.patch
x86mm-make-pagefault-killable.patch
mm-mem-hotplug-fix-section-mismatch-setup_per_zone_inactive_ratio-should-be-__meminit.patch
mm-mem-hotplug-recalculate-lowmem_reserve-when-memory-hotplug-occur.patch
mm-mem-hotplug-update-pcp-stat_threshold-when-memory-hotplug-occur.patch
mm-batch-activate_page-to-reduce-lock-contention.patch
mm-move-enum-vm_event_item-into-a-standalone-header-file.patch
memcg-count-the-soft_limit-reclaim-in-global-background-reclaim.patch
memcg-add-stats-to-monitor-soft_limit-reclaim.patch
add-the-pagefault-count-into-memcg-stats.patch
add-the-pagefault-count-into-memcg-stats-fix.patch
kexec-remove-kmsg_dump_kexec.patch
kexec-remove-kmsg_dump_kexec-fix.patch
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