Drain per-cpu lists when high-order allocations fail
Per-cpu pages can accidentally cause fragmentation because they are free, but
pinned pages in an otherwise contiguous block. When this patch is applied,
the per-cpu caches are drained after the direct-reclaim is entered if the
requested order is greater than 0. It simply reuses the code used by suspend
and hotplug.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fea1e3b..aa7e5d2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -876,7 +876,9 @@
}
spin_unlock_irqrestore(&zone->lock, flags);
}
+#endif /* CONFIG_PM */
+#if defined(CONFIG_HIBERNATION) || defined(CONFIG_PAGE_GROUP_BY_MOBILITY)
/*
* Spill all of this CPU's per-cpu pages back into the buddy allocator.
*/
@@ -888,7 +890,28 @@
__drain_pages(smp_processor_id());
local_irq_restore(flags);
}
-#endif /* CONFIG_HIBERNATION */
+
+void smp_drain_local_pages(void *arg)
+{
+ drain_local_pages();
+}
+
+/*
+ * Spill all the per-cpu pages from all CPUs back into the buddy allocator
+ */
+void drain_all_local_pages(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __drain_pages(smp_processor_id());
+ local_irq_restore(flags);
+
+ smp_call_function(smp_drain_local_pages, NULL, 0, 1);
+}
+#else
+void drain_all_local_pages(void) {}
+#endif /* CONFIG_HIBERNATION || CONFIG_PAGE_GROUP_BY_MOBILITY */
/*
* Free a 0-order page
@@ -1480,6 +1503,9 @@
cond_resched();
+ if (order != 0)
+ drain_all_local_pages();
+
if (likely(did_some_progress)) {
page = get_page_from_freelist(gfp_mask, order,
zonelist, alloc_flags);
