From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id 0B4C5900194 for ; Wed, 22 Jun 2011 10:37:23 -0400 (EDT) Date: Wed, 22 Jun 2011 16:37:18 +0200 From: Michal Hocko Subject: Re: "make -j" with memory.(memsw.)limit_in_bytes smaller than required -> livelock, even for unlimited processes Message-ID: <20110622143717.GE14343@tiehlicka.suse.cz> References: <4E00AFE6.20302@5t9.de> <20110622091018.16c14c78.kamezawa.hiroyu@jp.fujitsu.com> <20110622100615.0ab22219.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110622100615.0ab22219.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: Lutz Vieweg , Balbir Singh , Daisuke Nishimura , linux-mm@kvack.org On Wed 22-06-11 10:06:15, KAMEZAWA Hiroyuki wrote: > On Wed, 22 Jun 2011 09:10:18 +0900 > KAMEZAWA Hiroyuki wrote: > > > On Tue, 21 Jun 2011 16:51:18 +0200 > > Lutz Vieweg wrote: > > > > - but also at this time, if any other user (who has not exhausted > > > his memory limits) tries to access any file (at least on /tmp/, > > > as e.g. gcc does), even a simple "ls /tmp/", this operation > > > waits forever. (But "iostat" does not indicate any I/O activity.) > > > > > > > Hmm, it means your 'ls' gets some lock and wait for it. Then, what lock > > you wait for ? what w_chan is shown in 'ps -elf' ? > > > > I reproduced. And checked sysrq t. > > At first, some oom killers run. > Second, oom killer stops by some reason. (I think there are a KILLED process in memcg > but it doesn't exit. I'll check memcg' bypass logic.) > > Third, ls /tmp stops. > > Here is sysrq log. > == > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] ls D 0000000000000082 5448 22307 2799 0x10000000 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] ffff880623a7bb08 0000000000000086 ffff88033fffcc08 ffff88033fffbe70 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] ffff8805fa70c530 0000000000012880 ffff880623a7bfd8 ffff880623a7a010 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] ffff880623a7bfd8 0000000000012880 ffff8805f9c30000 ffff8805fa70c530 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] Call Trace: > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? sleep_on_page+0x20/0x20 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] io_schedule+0x8c/0xd0 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] sleep_on_page_killable+0xe/0x40 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] __wait_on_bit+0x5f/0x90 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] wait_on_page_bit_killable+0x75/0x80 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? autoremove_wake_function+0x40/0x40 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] __lock_page_or_retry+0x95/0xc0 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] filemap_fault+0x2df/0x4b0 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] __do_fault+0x55/0x530 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? unmap_region+0x110/0x140 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] handle_pte_fault+0xf7/0xb50 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? alloc_pages_current+0xaa/0x110 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? pte_alloc_one+0x37/0x50 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? sched_clock+0x9/0x10 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? trace_clock_local+0x9/0x10 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] handle_mm_fault+0x1d5/0x350 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] do_page_fault+0x140/0x470 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? trace_nowake_buffer_unlock_commit+0x43/0x60 > Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [] ? ftrace_raw_event_sys_exit+0xb3/ > == > > Then, waiting for some page bit...I/O of libc mapped pages ? > > Hmm. it seems buggy behavior. Okay, I'll dig this. I have seen similar behavior and posted a patch just today: https://lkml.org/lkml/2011/6/22/163 The point is that the original fault in page is locked when we try to charge a new COW page and things can get bad when we reach long taking OOM. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org