mm: numa: Limit NUMA scanning to migrate-on-fault VMAs (fc314724) · Commits · 戴 / test

There is a 90% regression observed with a large Oracle performance test on a 4 node system. Profiles indicated that the overhead was due to contention on sp_lock when looking up shared memory policies. These policies do not have the appropriate flags to allow them to be automatically balanced so trapping faults on them is pointless. This patch skips VMAs that do not have MPOL_F_MOF set. [riel@redhat.com: Initial patch] Signed-off-by:

Mel Gorman <mgorman@suse.de> Reported-and-tested-by:

Joe Mario <jmario@redhat.com> 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/1381141781-10992-32-git-send-email-mgorman@suse.de Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/linux/mempolicy.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -136,6 +136,7 @@ struct mempolicy mpol_shared_policy_lookup(struct shared_policy sp,

		struct mempolicy get_vma_policy(struct task_struct tsk,
		struct vm_area_struct *vma, unsigned long addr);
		bool vma_policy_mof(struct task_struct task, struct vm_area_struct vma);

		extern void numa_default_policy(void);
		extern void numa_policy_init(void);

kernel/sched/fair.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1130,7 +1130,7 @@ void task_numa_work(struct callback_head *work)
		vma = mm->mmap;
		}
		for (; vma; vma = vma->vm_next) {
		if (!vma_migratable(vma))
		if (!vma_migratable(vma) \|\| !vma_policy_mof(p, vma))
		continue;

		do {

mm/mempolicy.c

+24 −0

Original line number	Diff line number	Diff line
		@@ -1679,6 +1679,30 @@ struct mempolicy get_vma_policy(struct task_struct task,
		return pol;
		}

		bool vma_policy_mof(struct task_struct task, struct vm_area_struct vma)
		{
		struct mempolicy *pol = get_task_policy(task);
		if (vma) {
		if (vma->vm_ops && vma->vm_ops->get_policy) {
		bool ret = false;

		pol = vma->vm_ops->get_policy(vma, vma->vm_start);
		if (pol && (pol->flags & MPOL_F_MOF))
		ret = true;
		mpol_cond_put(pol);

		return ret;
		} else if (vma->vm_policy) {
		pol = vma->vm_policy;
		}
		}

		if (!pol)
		return default_policy.flags & MPOL_F_MOF;

		return pol->flags & MPOL_F_MOF;
		}

		static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
		{
		enum zone_type dynamic_policy_zone = policy_zone;

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