From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v5 8/8] sched/numa: drop unnecessary variable in task_weight
Date: Wed, 11 Dec 2013 09:50:28 -0500 [thread overview]
Message-ID: <1386773428-bwklwan0-mutt-n-horiguchi@ah.jp.nec.com> (raw)
In-Reply-To: <20131211092123.GV11295@suse.de>
On Wed, Dec 11, 2013 at 09:21:23AM +0000, Mel Gorman wrote:
> On Wed, Dec 11, 2013 at 08:50:01AM +0800, Wanpeng Li wrote:
> > Drop unnecessary total_faults variable in function task_weight to unify
> > task_weight and group_weight.
> >
> > Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> > Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>
> Nak.
>
> task_weight is called for tasks other than current. If p handles a fault
> in parallel then it can drop to 0 between when it's checked and used to
> divide resulting in an oops.
So we have the same race on group_weight(), and we have to add a local
variable to store p->numa_group->total_faults?
Thanks,
Naoya Horiguchi
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prev parent reply other threads:[~2013-12-11 14:51 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-11 0:49 [PATCH v5 0/8] mm: sched: numa: several fixups Wanpeng Li
2013-12-11 0:49 ` [PATCH v5 1/8] sched/numa: fix set cpupid on page migration twice against thp Wanpeng Li
2013-12-11 0:49 ` [PATCH v5 2/8] sched/numa: drop sysctl_numa_balancing_settle_count sysctl Wanpeng Li
2013-12-11 0:49 ` [PATCH v5 3/8] sched/numa: use wrapper function task_node to get node which task is on Wanpeng Li
2013-12-11 0:49 ` [PATCH v5 4/8] sched/numa: fix set cpupid on page migration twice against normal page Wanpeng Li
2013-12-11 9:01 ` Mel Gorman
2013-12-11 0:49 ` [PATCH v5 5/8] sched/numa: use wrapper function task_faults_idx to calculate index in group_faults Wanpeng Li
2013-12-11 9:02 ` Mel Gorman
2013-12-11 0:49 ` [PATCH v5 6/8] sched/numa: fix period_slot recalculation Wanpeng Li
2013-12-11 9:02 ` Mel Gorman
2013-12-11 0:50 ` [PATCH v5 7/8] sched/numa: fix record hinting faults check Wanpeng Li
2013-12-11 9:14 ` Mel Gorman
2013-12-11 9:41 ` Wanpeng Li
[not found] ` <20131211094156.GB26093@hacker.(null)>
2013-12-11 10:15 ` Mel Gorman
2013-12-11 0:50 ` [PATCH v5 8/8] sched/numa: drop unnecessary variable in task_weight Wanpeng Li
2013-12-11 9:21 ` Mel Gorman
2013-12-11 9:34 ` Wanpeng Li
2013-12-11 14:50 ` Naoya Horiguchi [this message]
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