From: Daniel J Blueman <daniel@numascale-asia.com>
To: Jiri Slaby <jslaby@suse.cz>
Cc: "Linux Kernel" <linux-kernel@vger.kernel.org>,
"Steffen Persvold" <sp@numascale.com>
Subject: Re: kswapd craziness round 2
Date: Mon, 18 Feb 2013 14:18:23 +0800 [thread overview]
Message-ID: <5121C7AF.2090803@numascale-asia.com> (raw)
On Monday, 18 February 2013 06:10:02 UTC+8, Jiri Slaby wrote:
> Hi,
>
> You still feel the sour taste of the "kswapd craziness in v3.7" thread,
> right? Welcome to the hell, part two :{.
>
> I believe this started happening after update from
> 3.8.0-rc4-next-20130125 to 3.8.0-rc7-next-20130211. The same as before,
> many hours of uptime are needed and perhaps some suspend/resume cycles
> too. Memory pressure is not high, plenty of I/O cache:
> # free
> total used free shared buffers cached
> Mem: 6026692 5571184 455508 0 351252 2016648
> -/+ buffers/cache: 3203284 2823408
> Swap: 0 0 0
>
> kswap is working very toughly though:
> root 580 0.6 0.0 0 0 ? S úno12 46:21
[kswapd0]
>
> This happens on I/O activity right now. For example by updatedb or find
> /. This is what the stack trace of kswapd0 looks like:
> [<ffffffff8113c431>] shrink_slab+0xa1/0x2d0
> [<ffffffff8113ecd1>] kswapd+0x541/0x930
> [<ffffffff810a3000>] kthread+0xc0/0xd0
> [<ffffffff816beb5c>] ret_from_fork+0x7c/0xb0
> [<ffffffffffffffff>] 0xffffffffffffffff
Likewise with 3.8-rc, I've been able to reproduce [1] a livelock
scenario which hoses the box and observe RCU stalls are observed [2].
There may be a connection; I'll do a bit more debugging in the next few
days.
Daniel
--- [1]
1. live-booted image using ramdisk
2. boot 3.8-rc with <16GB memory and without swap
3. run OpenMP NAS Parallel Benchmark dc.B against local disk (ie not
ramdisk)
4. observe hang O(30) mins later
--- [2]
[ 2675.587878] INFO: rcu_sched self-detected stall on CPU { 5} (t=24000
jiffies g=6313 c=6312 q=68)
--
Daniel J Blueman
Principal Software Engineer, Numascale Asia
next reply other threads:[~2013-02-18 6:18 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-18 6:18 Daniel J Blueman [this message]
2013-02-18 11:42 ` Hillf Danton
2013-02-18 15:05 ` Daniel J Blueman
2013-02-20 22:14 ` Jiri Slaby
2013-02-21 12:07 ` Hillf Danton
2013-02-24 21:27 ` Jiri Slaby
2013-02-28 17:02 ` Jiri Slaby
2013-03-01 14:02 ` Hillf Danton
2013-03-07 19:37 ` Jiri Slaby
2013-03-08 6:42 ` Hillf Danton
2013-03-08 7:29 ` Zlatko Calusic
2013-03-08 8:27 ` Hillf Danton
2013-03-08 23:21 ` Jiri Slaby
2013-03-19 16:59 ` Pádraig Brady
2013-03-20 4:12 ` Hillf Danton
2013-03-20 8:39 ` Jiri Slaby
-- strict thread matches above, loose matches on Subject: below --
2013-02-17 22:02 Jiri Slaby
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