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authorRik van Riel <riel@redhat.com>2013-10-07 11:29:34 +0100
committerIngo Molnar <mingo@kernel.org>2013-10-09 14:48:12 +0200
commitdabe1d992414a6456e60e41f1d1ad8affc6d444d (patch)
tree213b65fbc7864687d0ea9db96d7e768b6ff587cf /mm/memory.c
parent0ec8aa00f2b4dc457836ef4e2662b02483e94fb7 (diff)
downloadop-kernel-dev-dabe1d992414a6456e60e41f1d1ad8affc6d444d.zip
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sched/numa: Be more careful about joining numa groups
Due to the way the pid is truncated, and tasks are moved between CPUs by the scheduler, it is possible for the current task_numa_fault to group together tasks that do not actually share memory together. This patch adds a few easy sanity checks to task_numa_fault, joining tasks together if they share the same tsk->mm, or if the fault was on a page with an elevated mapcount, in a shared VMA. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> 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/1381141781-10992-57-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.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 9898eeb..823720c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3584,6 +3584,13 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
if (!pte_write(pte))
flags |= TNF_NO_GROUP;
+ /*
+ * Flag if the page is shared between multiple address spaces. This
+ * is later used when determining whether to group tasks together
+ */
+ if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED))
+ flags |= TNF_SHARED;
+
last_cpupid = page_cpupid_last(page);
page_nid = page_to_nid(page);
target_nid = numa_migrate_prep(page, vma, addr, page_nid);
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