kswapd craziness round 2

From: Jiri Slaby
Date: Sun Feb 17 2013 - 17:03:10 EST


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

Any ideas?

suse labs
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