Messages in this thread | | | Date | Fri, 9 Jan 2009 11:41:55 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH 1/4] memcg: fix for mem_cgroup_get_reclaim_stat_from_page |
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On Fri, 9 Jan 2009 11:34:58 +0900 Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> wrote:
> On Fri, 9 Jan 2009 10:05:31 +0900, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > On Fri, 09 Jan 2009 08:57:59 +0800 > > Li Zefan <lizf@cn.fujitsu.com> wrote: > > > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > > index e2996b8..62e69d8 100644 > > > > --- a/mm/memcontrol.c > > > > +++ b/mm/memcontrol.c > > > > @@ -559,6 +559,10 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page) > > > > return NULL; > > > > > > > > pc = lookup_page_cgroup(page); > > > > + smp_rmb(); > > > > > > It is better to add a comment to explain this smp_rmb. I think it's recommended > > > that every memory barrier has a comment. > > > > > Ah, yes. good point. > > > > Maybe text like this > > /* > > * Used bit is set without atomic ops but after smp_wmb(). > > * For making pc->mem_cgroup visible, insert smp_rmb() here. > > */ > > > OK. I'll add this comment. > > BTW, mem_cgroup_rotate_lru_list and mem_cgroup_add_lru_list have similar code. > (mem_cgroup_add_lru_list has some comment already.) > Should I update them too ? > please :) it's helpful. Sorry for my too short comment on orignal patch.
-Kame
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