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| author | Mel Gorman <mgorman@suse.de> | 2013-10-07 10:28:53 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-09 10:40:17 (GMT) |
| commit | b726b7dfb400c937546fa91cf8523dcb1aa2fc6e (patch) | |
| tree | b4a6f741b630bb22568536860f3f46e94c4e8904 /kernel/sched/fair.c | |
| parent | 9e645ab6d089f5822479a833c6977c785bcfffe3 (diff) | |
| download | linux-b726b7dfb400c937546fa91cf8523dcb1aa2fc6e.tar.xz | |
Revert "mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node"
PTE scanning and NUMA hinting fault handling is expensive so commit
5bca2303 ("mm: sched: numa: Delay PTE scanning until a task is scheduled
on a new node") deferred the PTE scan until a task had been scheduled on
another node. The problem is that in the purely shared memory case that
this may never happen and no NUMA hinting fault information will be
captured. We are not ruling out the possibility that something better
can be done here but for now, this patch needs to be reverted and depend
entirely on the scan_delay to avoid punishing short-lived processes.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-16-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 18 |
1 files changed, 0 insertions, 18 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 464207f..49b11fa 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -901,24 +901,6 @@ void task_numa_work(struct callback_head *work) return; /* - * We do not care about task placement until a task runs on a node - * other than the first one used by the address space. This is - * largely because migrations are driven by what CPU the task - * is running on. If it's never scheduled on another node, it'll - * not migrate so why bother trapping the fault. - */ - if (mm->first_nid == NUMA_PTE_SCAN_INIT) - mm->first_nid = numa_node_id(); - if (mm->first_nid != NUMA_PTE_SCAN_ACTIVE) { - /* Are we running on a new node yet? */ - if (numa_node_id() == mm->first_nid && - !sched_feat_numa(NUMA_FORCE)) - return; - - mm->first_nid = NUMA_PTE_SCAN_ACTIVE; - } - - /* * Reset the scan period if enough time has gone by. Objective is that * scanning will be reduced if pages are properly placed. As tasks * can enter different phases this needs to be re-examined. Lacking |