Re: "make -j" with memory.(memsw.)limit_in_bytes smaller than required -> livelock, even for unlimited processes

KAMEZAWA Hiroyuki
2011-06-22T01:13:17Z

On Wed, 22 Jun 2011 09:10:18 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> On Tue, 21 Jun 2011 16:51:18 +0200
> Lutz Vieweg <lvml@5t9.de> 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] [<ffffffff810ee900>] ? sleep_on_page+0x20/0x20
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff8154f40c>] io_schedule+0x8c/0xd0
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810ee90e>] sleep_on_page_killable+0xe/0x40
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff8154fddf>] __wait_on_bit+0x5f/0x90
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810eeab5>] wait_on_page_bit_killable+0x75/0x80
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810791f0>] ? autoremove_wake_function+0x40/0x40
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810eec35>] __lock_page_or_retry+0x95/0xc0
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810efe7f>] filemap_fault+0x2df/0x4b0
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81115685>] __do_fault+0x55/0x530
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81119150>] ? unmap_region+0x110/0x140
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81115c57>] handle_pte_fault+0xf7/0xb50
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff8112f87a>] ? alloc_pages_current+0xaa/0x110
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff8103a857>] ? pte_alloc_one+0x37/0x50
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81011ea9>] ? sched_clock+0x9/0x10
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810c0ec9>] ? trace_clock_local+0x9/0x10
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81116885>] handle_mm_fault+0x1d5/0x350
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81555090>] do_page_fault+0x140/0x470
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff810ce4c3>] ? trace_nowake_buffer_unlock_commit+0x43/0x60
Jun 22 10:04:29 bluextal kernel: [ 1366.149012] [<ffffffff81015c83>] ? 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.

Thanks,
-Kame