On Mon, 13 Jun 2011 14:25:01 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, 13 Jun 2011 12:16:48 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > > >From 18b12e53f1cdf6d7feed1f9226c189c34866338c Mon Sep 17 00:00:00 2001 > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > Date: Mon, 13 Jun 2011 11:25:43 +0900 > > Subject: [PATCH 5/5] memcg: fix percpu cached charge draining frequency > > > > For performance, memory cgroup caches some "charge" from res_counter > > into per cpu cache. This works well but because it's cache, > > it needs to be flushed in some cases. Typical cases are > > 1. when someone hit limit. > > 2. when rmdir() is called and need to charges to be 0. > > > > But "1" has problem. > > > > Recently, with large SMP machines, we see many kworker runs because > > of flushing memcg's cache. Bad things in implementation are > > that even if a cpu contains a cache for memcg not related to > > a memcg which hits limit, drain code is called. > > > > This patch does > > A) check percpu cache contains a useful data or not. > > B) check other asynchronous percpu draining doesn't run. > > C) don't call local cpu callback. > > D) don't call at softlimit reclaim. > > > > > > ... > > > > +DEFINE_MUTEX(percpu_charge_mutex); > > I made this static. If we later wish to give it kernel-wide scope then > "percpu_charge_mutex" will not be a good choice of name. Thank you. And, yes..... memcg_cached_charge_mutex ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>