summaryrefslogtreecommitdiff
path: root/mm/memory.c
diff options
context:
space:
mode:
authorMel Gorman <mgorman@suse.de>2013-10-07 11:28:50 +0100
committerIngo Molnar <mingo@kernel.org>2013-10-09 12:39:50 +0200
commita1a46184e34cfd0764f06a54870defa052b0a094 (patch)
treeb4d12f1d23963fb3de14cf8d81f7979c4f58d95a /mm/memory.c
parentf123d74abf91574837d14e5ea58f6a779a387bf5 (diff)
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.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 42ae82ee04c1..ed51f15136ee 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);