On 05/15/2012 06:46 AM, KAMEZAWA Hiroyuki wrote: > (2012/05/12 2:44), Glauber Costa wrote: > >> This patch creates a mechanism that skip memcg allocations during >> certain pieces of our core code. It basically works in the same way >> as preempt_disable()/preempt_enable(): By marking a region under >> which all allocations will be accounted to the root memcg. >> >> We need this to prevent races in early cache creation, when we >> allocate data using caches that are not necessarily created already. >> >> Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx> >> CC: Christoph Lameter<cl@xxxxxxxxx> >> CC: Pekka Enberg<penberg@xxxxxxxxxxxxxx> >> CC: Michal Hocko<mhocko@xxxxxxx> >> CC: Kamezawa Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx> >> CC: Johannes Weiner<hannes@xxxxxxxxxxx> >> CC: Suleiman Souhlal<suleiman@xxxxxxxxxx> > > > The concept seems okay to me but... > >> --- >> include/linux/sched.h | 1 + >> mm/memcontrol.c | 25 +++++++++++++++++++++++++ >> 2 files changed, 26 insertions(+), 0 deletions(-) >> >> diff --git a/include/linux/sched.h b/include/linux/sched.h >> index 81a173c..0501114 100644 >> --- a/include/linux/sched.h >> +++ b/include/linux/sched.h >> @@ -1613,6 +1613,7 @@ struct task_struct { >> unsigned long nr_pages; /* uncharged usage */ >> unsigned long memsw_nr_pages; /* uncharged mem+swap usage */ >> } memcg_batch; >> + atomic_t memcg_kmem_skip_account; > > > If only 'current' thread touch this, you don't need to make this atomic counter. > you can use 'long'. > You're absolutely right, Kame, thanks. I first used atomic_t because I had it tested against current->mm->owner. Do you, btw, agree to use current instead of owner here? You can find the rationale in earlier mails between me and Suleiman. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html