Arkadiusz Miskiewicz wrote:
> > > vmstat_update() and submit_flushes() remained pending for about 110
> > > seconds. If xlog_cil_push_work() were spinning inside GFP_NOFS
> > > allocation, it should be reported as MemAlloc: traces, but no such lines
> > > are recorded. I don't know why xlog_cil_push_work() did not call
> > > schedule() for so long. Anyway, applying
> > > http://lkml.kernel.org/r/20151111160336.GD1432@xxxxxxxxxxxxxx should
> > > solve vmstat_update() part.
> >
> > To apply that patch on top of 4.1.13 I also had to apply patches listed
> > below.
> >
> > So in summary appllied:
> > http://sprunge.us/GYBb
> > http://sprunge.us/XWUX
> > http://sprunge.us/jZjV
>
> I've tried more to trigger "page allocation failure" with usual actions that
> triggered it previously but couldn't reproduce. With these patches applied it
> doesn't happen.
>
> Logs from my tests:
>
> http://ixion.pld-linux.org/~arekm/log-mm-3.txt.gz
> http://ixion.pld-linux.org/~arekm/log-mm-4.txt.gz (with swap added)
>
Good.
vmstat_update() and submit_flushes() are no longer pending for long.
log-mm-4.txt:Nov 14 16:40:08 srv kernel: [167753.393960] pending:
vmstat_shepherd, vmpressure_work_fn
log-mm-4.txt:Nov 14 16:40:08 srv kernel: [167753.393984] pending:
submit_flushes [md_mod]
log-mm-4.txt:Nov 14 16:41:08 srv kernel: [167813.439405] pending:
submit_flushes [md_mod]
log-mm-4.txt:Nov 14 17:17:19 srv kernel: [169985.104806] pending:
vmstat_shepherd
I think that the vmstat statistics now have correct values.
> But are these patches solving the problem or just hiding it?
>
Excuse me but I can't judge.
If you are interested in monitoring how vmstat statistics are changing
under stalled condition, you can try below patch.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 35a46b4..3de3a14 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2794,8 +2794,7 @@ static int kmallocwd(void *unused)
rcu_read_unlock();
preempt_enable();
show_workqueue_state();
- if (dump_target_pid <= 0)
- dump_target_pid = -pid;
+ show_mem(0);
/* Wait until next timeout duration. */
schedule_timeout_interruptible(kmallocwd_timeout);
if (memalloc_counter[index])
|