Re: [patch 0/7] improve memcg oom killer robustness v2

[Michal Hocko <mhocko@suse.cz>]

On Wed 18-09-13 20:02:39, azurIt wrote:
> > CC: "Johannes Weiner" <hannes@cmpxchg.org>, "Andrew Morton" <akpm@linux-foundation.org>, "David Rientjes" <rientjes@google.com>, "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>, "KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com>, linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
> >On Wed 18-09-13 16:33:06, azurIt wrote:
> >> > CC: "Johannes Weiner" <hannes@cmpxchg.org>, "Andrew Morton" <akpm@linux-foundation.org>, "David Rientjes" <rientjes@google.com>, "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>, "KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com>, linux-mm@kvack.org, cgroups@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
> >> >On Wed 18-09-13 16:03:04, azurIt wrote:
> >> >[..]
> >> >> I was finally able to get stack of problematic process :) I saved it
> >> >> two times from the same process, as Michal suggested (i wasn't able to
> >> >> take more). Here it is:
> >> >> 
> >> >> First (doesn't look very helpfull):
> >> >> [<ffffffffffffffff>] 0xffffffffffffffff
> >> >
> >> >No it is not.
> >> > 
> >> >> Second:
> >> >> [<ffffffff810e17d1>] shrink_zone+0x481/0x650
> >> >> [<ffffffff810e2ade>] do_try_to_free_pages+0xde/0x550
> >> >> [<ffffffff810e310b>] try_to_free_pages+0x9b/0x120
> >> >> [<ffffffff81148ccd>] free_more_memory+0x5d/0x60
> >> >> [<ffffffff8114931d>] __getblk+0x14d/0x2c0
> >> >> [<ffffffff8114c973>] __bread+0x13/0xc0
> >> >> [<ffffffff811968a8>] ext3_get_branch+0x98/0x140
> >> >> [<ffffffff81197497>] ext3_get_blocks_handle+0xd7/0xdc0
> >> >> [<ffffffff81198244>] ext3_get_block+0xc4/0x120
> >> >> [<ffffffff81155b8a>] do_mpage_readpage+0x38a/0x690
> >> >> [<ffffffff81155ffb>] mpage_readpages+0xfb/0x160
> >> >> [<ffffffff811972bd>] ext3_readpages+0x1d/0x20
> >> >> [<ffffffff810d9345>] __do_page_cache_readahead+0x1c5/0x270
> >> >> [<ffffffff810d9411>] ra_submit+0x21/0x30
> >> >> [<ffffffff810cfb90>] filemap_fault+0x380/0x4f0
> >> >> [<ffffffff810ef908>] __do_fault+0x78/0x5a0
> >> >> [<ffffffff810f2b24>] handle_pte_fault+0x84/0x940
> >> >> [<ffffffff810f354a>] handle_mm_fault+0x16a/0x320
> >> >> [<ffffffff8102715b>] do_page_fault+0x13b/0x490
> >> >> [<ffffffff815cb87f>] page_fault+0x1f/0x30
> >> >> [<ffffffffffffffff>] 0xffffffffffffffff
> >> >
> >> >This is the direct reclaim path. You are simply running out of memory
> >> >globaly. There is no memcg specific code in that trace.
> >> 
> >> 
> >> No, i'm not. Here is htop and server graphs from this case:
> >
> >Bahh, right you are. I didn't look at the trace carefully. It is
> >free_more_memory which calls the direct reclaim shrinking.
> >
> >Sorry about the confusion
> 
> 
> Happens again and this time i got 5x this:
> [<ffffffffffffffff>] 0xffffffffffffffff
> 
> :( it's probably looping very fast so i need to have some luck

Or it is looping in the userspace.
-- 
Michal Hocko
SUSE Labs