sched/numa: Retry placement more frequently when misplaced
When tasks have not converged on their preferred nodes yet, we want to retry fairly often, to make sure we do not migrate a task's memory to an undesirable location, only to have to move it again later. This patch reduces the interval at which migration is retried, when the task's numa_scan_period is small. Signed-off-by: Rik van Riel <riel@redhat.com> Tested-by: Vinod Chegu <chegu_vinod@hp.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1397235629-16328-3-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -1326,12 +1326,15 @@ static int task_numa_migrate(struct task_struct *p)
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/* Attempt to migrate a task to a CPU on the preferred node. */
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/* Attempt to migrate a task to a CPU on the preferred node. */
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static void numa_migrate_preferred(struct task_struct *p)
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static void numa_migrate_preferred(struct task_struct *p)
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{
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{
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unsigned long interval = HZ;
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/* This task has no NUMA fault statistics yet */
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/* This task has no NUMA fault statistics yet */
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if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory))
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if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory))
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return;
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return;
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/* Periodically retry migrating the task to the preferred node */
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/* Periodically retry migrating the task to the preferred node */
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p->numa_migrate_retry = jiffies + HZ;
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interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16);
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p->numa_migrate_retry = jiffies + interval;
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/* Success if task is already running on preferred CPU */
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/* Success if task is already running on preferred CPU */
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if (task_node(p) == p->numa_preferred_nid)
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if (task_node(p) == p->numa_preferred_nid)
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