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| author | Mel Gorman <mgorman@suse.de> | 2013-10-07 11:28:50 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-09 12:39:50 +0200 |
| commit | a1a46184e34cfd0764f06a54870defa052b0a094 (patch) | |
| tree | b4d12f1d23963fb3de14cf8d81f7979c4f58d95a /mm/memory.c | |
| parent | f123d74abf91574837d14e5ea58f6a779a387bf5 (diff) | |
| download | op-kernel-dev-a1a46184e34cfd0764f06a54870defa052b0a094.zip op-kernel-dev-a1a46184e34cfd0764f06a54870defa052b0a094.tar.gz | |
mm: numa: Do not migrate or account for hinting faults on the zero page
The zero page is not replicated between nodes and is often shared between
processes. The data is read-only and likely to be cached in local CPUs
if heavily accessed meaning that the remote memory access cost is less
of a concern. This patch prevents trapping faults on the zero pages. For
tasks using the zero page this will reduce the number of PTE updates,
TLB flushes and hinting faults.
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>
[ Correct use of is_huge_zero_page]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-13-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index 42ae82e..ed51f15 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3564,6 +3564,7 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, pte_unmap_unlock(ptep, ptl); return 0; } + BUG_ON(is_zero_pfn(page_to_pfn(page))); page_nid = page_to_nid(page); target_nid = numa_migrate_prep(page, vma, addr, page_nid); |
