From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Mel Gorman <mgorman@suse.de>
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: Thu, 4 Jul 2013 18:18:23 +0530 [thread overview]
Message-ID: <20130704124823.GB29916@linux.vnet.ibm.com> (raw)
In-Reply-To: <1372861300-9973-12-git-send-email-mgorman@suse.de>
* 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?
> + return;
> + }
> +
> /* Allocate buffer to track faults on a per-node basis */
> if (unlikely(!p->numa_faults)) {
> int size = sizeof(*p->numa_faults) * 2 * nr_node_ids;
> @@ -1072,16 +1076,18 @@ void task_numa_work(struct callback_head *work)
> end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
> end = min(end, vma->vm_end);
> nr_pte_updates += change_prot_numa(vma, start, end);
> - pages -= (end - start) >> PAGE_SHIFT;
> -
> - start = end;
>
> /*
> * Scan sysctl_numa_balancing_scan_size but ensure that
> - * least one PTE is updated so that unused virtual
> - * address space is quickly skipped
> + * at least one PTE is updated so that unused virtual
> + * address space is quickly skipped.
> */
> - if (pages <= 0 && nr_pte_updates)
> + if (nr_pte_updates)
> + pages -= (end - start) >> PAGE_SHIFT;
> +
> + start = end;
> +
> + if (pages <= 0)
> goto out;
> } while (end != vma->vm_end);
> }
> --
> 1.8.1.4
>
--
Thanks and Regards
Srikar Dronamraju
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next prev parent reply other threads:[~2013-07-04 12:48 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 [this message]
2013-07-05 10:07 ` Mel Gorman
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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