From: Mel Gorman <mgorman@suse.de>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 11/13] sched: Check current->mm before allocating NUMA faults
Date: Fri, 5 Jul 2013 11:07:41 +0100 [thread overview]
Message-ID: <20130705100741.GV1875@suse.de> (raw)
In-Reply-To: <20130704124823.GB29916@linux.vnet.ibm.com>
On Thu, Jul 04, 2013 at 06:18:23PM +0530, Srikar Dronamraju wrote:
> * Mel Gorman <mgorman@suse.de> [2013-07-03 15:21:38]:
>
> > task_numa_placement checks current->mm but after buffers for faults
> > have already been uselessly allocated. Move the check earlier.
> >
> > [peterz@infradead.org: Identified the problem]
> > Signed-off-by: Mel Gorman <mgorman@suse.de>
> > ---
> > kernel/sched/fair.c | 22 ++++++++++++++--------
> > 1 file changed, 14 insertions(+), 8 deletions(-)
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 336074f..3c796b0 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -870,8 +870,6 @@ static void task_numa_placement(struct task_struct *p)
> > int seq, nid, max_nid = 0;
> > unsigned long max_faults = 0;
> >
> > - if (!p->mm) /* for example, ksmd faulting in a user's mm */
> > - return;
> > seq = ACCESS_ONCE(p->mm->numa_scan_seq);
> > if (p->numa_scan_seq == seq)
> > return;
> > @@ -945,6 +943,12 @@ void task_numa_fault(int last_nid, int node, int pages, bool migrated)
> > if (!sched_feat_numa(NUMA))
> > return;
> >
> > + /* for example, ksmd faulting in a user's mm */
> > + if (!p->mm) {
> > + p->numa_scan_period = sysctl_numa_balancing_scan_period_max;
>
> Naive question:
> Why are we resetting the scan_period?
>
At the time I wrote it I was thinking of tick times and meant to recheck
if it's necessary but then it slipped my mind. The reset is unnecessary
as curr->mm is already checked.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2013-07-05 10:07 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-03 14:21 [PATCH 0/13] Basic scheduler support for automatic NUMA balancing V2 Mel Gorman
2013-07-03 14:21 ` [PATCH 01/13] mm: numa: Document automatic NUMA balancing sysctls Mel Gorman
2013-07-03 14:21 ` [PATCH 02/13] sched: Track NUMA hinting faults on per-node basis Mel Gorman
2013-07-03 14:21 ` [PATCH 03/13] sched: Select a preferred node with the most numa hinting faults Mel Gorman
2013-07-03 14:21 ` [PATCH 04/13] sched: Update NUMA hinting faults once per scan Mel Gorman
2013-07-03 14:21 ` [PATCH 05/13] sched: Favour moving tasks towards the preferred node Mel Gorman
2013-07-03 14:21 ` [PATCH 06/13] sched: Reschedule task on preferred NUMA node once selected Mel Gorman
2013-07-04 12:26 ` Srikar Dronamraju
2013-07-04 13:29 ` Mel Gorman
2013-07-03 14:21 ` [PATCH 07/13] sched: Split accounting of NUMA hinting faults that pass two-stage filter Mel Gorman
2013-07-03 21:56 ` Johannes Weiner
2013-07-04 9:23 ` Mel Gorman
2013-07-04 14:24 ` Rik van Riel
2013-07-04 19:36 ` Johannes Weiner
2013-07-05 9:41 ` Mel Gorman
2013-07-05 10:48 ` Peter Zijlstra
2013-07-03 14:21 ` [PATCH 08/13] sched: Increase NUMA PTE scanning when a new preferred node is selected Mel Gorman
2013-07-03 14:21 ` [PATCH 09/13] sched: Favour moving tasks towards nodes that incurred more faults Mel Gorman
2013-07-03 18:27 ` Peter Zijlstra
2013-07-04 9:25 ` Mel Gorman
2013-07-03 14:21 ` [PATCH 10/13] sched: Set the scan rate proportional to the size of the task being scanned Mel Gorman
2013-07-03 14:21 ` [PATCH 11/13] sched: Check current->mm before allocating NUMA faults Mel Gorman
2013-07-03 15:33 ` Mel Gorman
2013-07-04 12:48 ` Srikar Dronamraju
2013-07-05 10:07 ` Mel Gorman [this message]
2013-07-03 14:21 ` [PATCH 12/13] mm: numa: Scan pages with elevated page_mapcount Mel Gorman
2013-07-03 18:35 ` Peter Zijlstra
2013-07-04 9:27 ` Mel Gorman
2013-07-03 18:41 ` Peter Zijlstra
2013-07-04 9:32 ` Mel Gorman
2013-07-03 18:42 ` Peter Zijlstra
2013-07-03 14:21 ` [PATCH 13/13] sched: Account for the number of preferred tasks running on a node when selecting a preferred node Mel Gorman
2013-07-03 18:32 ` Peter Zijlstra
2013-07-04 9:37 ` Mel Gorman
2013-07-04 13:07 ` Srikar Dronamraju
2013-07-04 13:54 ` Mel Gorman
2013-07-04 14:06 ` Peter Zijlstra
2013-07-04 14:40 ` Mel Gorman
2013-07-03 16:19 ` [PATCH 0/13] Basic scheduler support for automatic NUMA balancing V2 Mel Gorman
2013-07-03 16:26 ` Mel Gorman
2013-07-04 18:02 ` [PATCH RFC WIP] Process weights based scheduling for better consolidation Srikar Dronamraju
2013-07-05 10:16 ` Peter Zijlstra
2013-07-05 12:49 ` Srikar Dronamraju
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