mm: numa: Do not group on RO pages
And here's a little something to make sure not the whole world ends up
in a single group.
As while we don't migrate shared executable pages, we do scan/fault on
them. And since everybody links to libc, everybody ends up in the same
group.
Suggested-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
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>
Link: http://lkml.kernel.org/r/1381141781-10992-47-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index becf92c..7ab4e32 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1285,6 +1285,7 @@
int target_nid, last_cpupid = -1;
bool page_locked;
bool migrated = false;
+ int flags = 0;
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(pmd, *pmdp)))
@@ -1299,6 +1300,14 @@
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
/*
+ * Avoid grouping on DSO/COW pages in specific and RO pages
+ * in general, RO pages shouldn't hurt as much anyway since
+ * they can be in shared cache state.
+ */
+ if (!pmd_write(pmd))
+ flags |= TNF_NO_GROUP;
+
+ /*
* Acquire the page lock to serialise THP migrations but avoid dropping
* page_table_lock if at all possible
*/
@@ -1343,8 +1352,10 @@
spin_unlock(&mm->page_table_lock);
migrated = migrate_misplaced_transhuge_page(mm, vma,
pmdp, pmd, addr, page, target_nid);
- if (migrated)
+ if (migrated) {
+ flags |= TNF_MIGRATED;
page_nid = target_nid;
+ }
goto out;
clear_pmdnuma:
@@ -1362,7 +1373,7 @@
page_unlock_anon_vma_read(anon_vma);
if (page_nid != -1)
- task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, migrated);
+ task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags);
return 0;
}