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]>
---
Kconfig | 4 ++++
page_alloc.c | 32 +++++++++++++++++++++++++++++---
2 files changed, 33 insertions(+), 3 deletions(-)
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.18-rc5-mm1-004_configurable/mm/Kconfig linux-2.6.18-rc5-mm1-005_drainpercpu/mm/Kconfig
--- linux-2.6.18-rc5-mm1-004_configurable/mm/Kconfig 2006-09-04 18:34:33.000000000 +0100
+++ linux-2.6.18-rc5-mm1-005_drainpercpu/mm/Kconfig 2006-09-07 19:16:11.000000000 +0100
@@ -242,3 +242,7 @@ config READAHEAD_SMOOTH_AGING
- have the danger of readahead thrashing(i.e. memory tight)
This feature is only available on non-NUMA systems.
+
+config NEED_DRAIN_PERCPU_PAGES
+ def_bool y
+ depends on PM || HOTPLUG_CPU || PAGEALLOC_ANTIFRAG
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.18-rc5-mm1-004_configurable/mm/page_alloc.c linux-2.6.18-rc5-mm1-005_drainpercpu/mm/page_alloc.c
--- linux-2.6.18-rc5-mm1-004_configurable/mm/page_alloc.c 2006-09-07 19:14:30.000000000 +0100
+++ linux-2.6.18-rc5-mm1-005_drainpercpu/mm/page_alloc.c 2006-09-07 19:16:38.000000000 +0100
@@ -796,7 +796,7 @@ void drain_node_pages(int nodeid)
}
#endif
-#if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
+#ifdef CONFIG_NEED_DRAIN_PERCPU_PAGES
static void __drain_pages(unsigned int cpu)
{
unsigned long flags;
@@ -823,7 +823,7 @@ static void __drain_pages(unsigned int c
}
}
}
-#endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */
+#endif /* CONFIG_DRAIN_PERCPU_PAGES */
#ifdef CONFIG_PM
@@ -860,7 +860,9 @@ void mark_free_pages(struct zone *zone)
spin_unlock_irqrestore(&zone->lock, flags);
}
+#endif /* CONFIG_PM */
+#if defined(CONFIG_PM) || defined(CONFIG_PAGEALLOC_ANTIFRAG)
/*
* Spill all of this CPU's per-cpu pages back into the buddy allocator.
*/
@@ -872,7 +874,28 @@ void drain_local_pages(void)
__drain_pages(smp_processor_id());
local_irq_restore(flags);
}
-#endif /* CONFIG_PM */
+
+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_PM || CONFIG_PAGEALLOC_ANTIFRAG */
/*
* Free a 0-order page
@@ -1232,6 +1255,9 @@ rebalance:
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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