From 1bc115d87dffd1c43bdc3c9c9d1e3a51c195d18e Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Mon, 7 Oct 2013 11:29:05 +0100 Subject: 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 Reviewed-by: Rik van Riel Cc: Andrea Arcangeli Cc: Johannes Weiner Cc: Srikar Dronamraju Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1381141781-10992-28-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar --- mm/mprotect.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'mm/mprotect.c') 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; } -- cgit v1.2.3