On Wed, 11 Jan 2012 07:25:20 +0400 "Nikolay S." <nowhere@xxxxxxxxxxxxxxxx> wrote: > __ ____., 10/01/2012 __ 14:33 -0800, Andrew Morton __________: > > On Tue, 27 Dec 2011 13:56:58 +0900 > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > > > > Hmm, if I understand correctly, > > > > > > - dd's speed down is caused by kswapd's cpu consumption. > > > - kswapd's cpu consumption is enlarged by shrink_slab() (by perf) > > > - kswapd can't stop because NORMAL zone is small. > > > - memory reclaim speed is enough because dd can't get enough cpu. > > > > > > I wonder reducing to call shrink_slab() may be a help but I'm not sure > > > where lock conention comes from... > > > > Nikolay, it sounds as if this problem has only recently started > > happening? Was 3.1 OK? > > > > If so, we should work out what we did post-3.1 to cause this. > > Yes, 3.1. was ok. > Recently I have upgraded to 3.2, and I can not reproduce the problem. > I'm now at 5 days uptime, the machine usage pattern, the software - all > the same, but the problem is not visible anymore: > > PID USER S %CPU %MEM TIME+ SWAP COMMAND > 14822 nowhere R 30 0.2 0:01.52 10m dd > 416 root S 7 0.0 6:26.72 0 kswapd0 > > (also, kswapd run time after 5 days is only 6,5 seconds, whereas with > -rc5 it was 22 seconds after 5 days). > > I can provide similar traces to see what has changed in kswapd's > activities (if it is of any value) OK, thanks for the followup. I suppose we assume this is fixed unless someone reports it in 3.2. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>