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authorMel Gorman <mgorman@suse.de>2013-10-07 14:29:05 +0400
committerIngo Molnar <mingo@kernel.org>2013-10-09 14:40:32 +0400
commit1bc115d87dffd1c43bdc3c9c9d1e3a51c195d18e (patch)
tree56a26b4f4fe089e3dd1df5a26877d1e4c0114d35 /mm/mprotect.c
parent9ff1d9ff3c2c8ab3feaeb2e8056a07ca293f7bde (diff)
downloadlinux-1bc115d87dffd1c43bdc3c9c9d1e3a51c195d18e.tar.xz
mm: numa: Scan pages with elevated page_mapcount
Currently automatic NUMA balancing is unable to distinguish between false shared versus private pages except by ignoring pages with an elevated page_mapcount entirely. This avoids shared pages bouncing between the nodes whose task is using them but that is ignored quite a lot of data. This patch kicks away the training wheels in preparation for adding support for identifying shared/private pages is now in place. The ordering is so that the impact of the shared/private detection can be easily measured. Note that the patch does not migrate shared, file-backed within vmas marked VM_EXEC as these are generally shared library pages. Migrating such pages is not beneficial as there is an expectation they are read-shared between caches and iTLB and iCache pressure is generally low. 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/1381141781-10992-28-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/mprotect.c')
-rw-r--r--mm/mprotect.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 2da33dca6134..41e02923fcd9 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -69,9 +69,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
if (last_nid != this_nid)
all_same_node = false;
- /* only check non-shared pages */
- if (!pte_numa(oldpte) &&
- page_mapcount(page) == 1) {
+ if (!pte_numa(oldpte)) {
ptent = pte_mknuma(ptent);
updated = true;
}