______________________________________________________________ > Od: "Kamezawa Hiroyuki" <kamezawa.hir...@jp.fujitsu.com> > Komu: azurIt <azu...@pobox.sk> > Dátum: 22.11.2012 01:27 > Predmet: Re: memory-cgroup bug > > CC: linux-kernel@vger.kernel.org, "linux-mm" <linux...@kvack.org> >(2012/11/22 4:02), azurIt wrote: >> Hi, >> >> i'm using memory cgroup for limiting our users and having a really strange >> problem when a cgroup gets out of its memory limit. It's very strange >> because it happens only sometimes (about once per week on random user), out >> of memory is usually handled ok. This happens when problem occures: >> - no new processes can be started for this cgroup >> - current processes are freezed and taking 100% of CPU >> - when i try to 'strace' any of current processes, the whole strace >> freezes until process is killed (strace cannot be terminated by CTRL-c) >> - problem can be resolved by raising memory limit for cgroup or killing of >> few processes inside cgroup so some memory is freed >> >> I also garbbed the content of /proc/<pid>/stack of freezed process: >> [<ffffffff8110a9c1>] mem_cgroup_handle_oom+0x241/0x3b0 >> [<ffffffff8110b5ab>] T.1146+0x5ab/0x5c0 >> [<ffffffff8110ba56>] mem_cgroup_charge_common+0x56/0xa0 >> [<ffffffff8110bae5>] mem_cgroup_newpage_charge+0x45/0x50 >> [<ffffffff810ec54e>] do_wp_page+0x14e/0x800 >> [<ffffffff810eda34>] handle_pte_fault+0x264/0x940 >> [<ffffffff810ee248>] handle_mm_fault+0x138/0x260 >> [<ffffffff810270ed>] do_page_fault+0x13d/0x460 >> [<ffffffff815b53ff>] page_fault+0x1f/0x30 >> [<ffffffffffffffff>] 0xffffffffffffffff >> >> I'm currently using kernel 3.2.34 but i'm having this problem since 2.6.32. >> >> Any ideas? Thnx. >> > >Under OOM in memcg, only one process is allowed to work. Because processes >tends to use up >CPU at memory shortage. other processes are freezed. > > >Then, the problem here is the one process which uses CPU. IIUC, 'freezed' >threads are >in sleep and never use CPU. It's expected oom-killer or memory-reclaim can >solve the probelm. > >What is your memcg's memory.oom_control value ?
oom_kill_disable 0 >and process's oom_adj values ? (/proc/<pid>/oom_adj, /proc/<pid>/oom_score_adj) when i look to a random user PID (Apache web server): oom_adj = 0 oom_score_adj = 0 I can look also to the data of 'freezed' proces if you need it but i will have to wait until problem occurs again. The main problem is that when this problem happens, it's NOT resolved automatically by kernel/OOM and user of cgroup, where it happend, has non-working services until i kill his processes by hand. I'm sure that all 'freezed' processes are taking very much CPU because also server load goes really high - next time i will make a screenshot of htop. I really wonder why OOM is __sometimes__ not resolving this (it's usually is, only sometimes not). Thank you! azur -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
