Re: [PATCH] memcg: Fix race condition in memcg_check_events() with this_cpu usage

Steven Rostedt
2011-09-24T02:41:37Z

On Fri, 2011-09-23 at 19:39 -0700, Greg Thelen wrote:
> cc: updated Balbir Singh email address
>
> On Fri, Sep 23, 2011 at 7:34 PM, Greg Thelen <gthelen@google.com> wrote:
> > On Fri, Sep 23, 2011 at 5:54 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> >> From: Steven Rostedt <srostedt@redhat.com>
> >>
> >> The code in memcg_check_events() calls this_cpu_read() on
> >> different variables without disabling preemption, and can cause
> >> the calculations to be done from two different CPU variables.
> >>
> >> Disable preemption throughout the check to keep apples and oranges
> >> from becoming a mixed drink.
> >>
> >> [ Added this_cpu to __this_cpu conversion by Johannes ]
> >>
> >> Cc: Greg Thelen <gthelen@google.com>
> >> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> >> Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
>
> Correction:
> Cc: Balbir Singh <bsingharora@gmail.com>

Thanks, I was starting to hate that "return mail to sender" thing.

-- Steve

>
> >> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> >> Cc: Andrew Morton <akpm@linux-foundation.org>
> >> Cc: Thomas Gleixner <tglx@linutronix.de>
> >> Cc: Peter Zijlstra <peterz@infradead.org>
> >> Cc: Christoph Lameter <cl@linux.com>
> >> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> >> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> >> Link: http://lkml.kernel.org/r/20110919212641.015320989@goodmis.org
> >
> > Looks good to me. Thanks.
> >
> > Reviewed-by: Greg Thelen <gthelen@google.com>
> >