Messages in this thread | | | Date | Mon, 18 Feb 2013 14:18:23 +0800 | From | Daniel J Blueman <> | Subject | Re: kswapd craziness round 2 |
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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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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