Subject: 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 <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
mm/page_alloc.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff
linux-2.6.23-rc5-006-group-short-lived-and-reclaimable-kernel-allocations/mm/page_alloc.c
linux-2.6.23-rc5-007-drain-per-cpu-lists-when-high-order-allocations-fail/mm/page_alloc.c
---
linux-2.6.23-rc5-006-group-short-lived-and-reclaimable-kernel-allocations/mm/page_alloc.c
2007-09-02 16:20:31.000000000 +0100
+++
linux-2.6.23-rc5-007-drain-per-cpu-lists-when-high-order-allocations-fail/mm/page_alloc.c
2007-09-02 16:20:48.000000000 +0100
@@ -852,6 +852,7 @@ void mark_free_pages(struct zone *zone)
}
spin_unlock_irqrestore(&zone->lock, flags);
}
+#endif /* CONFIG_PM */
/*
* Spill all of this CPU's per-cpu pages back into the buddy allocator.
@@ -864,7 +865,25 @@ void drain_local_pages(void)
__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);
+}
/*
* Free a 0-order page
@@ -1452,6 +1471,9 @@ nofail_alloc:
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);
-
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