Subject: + mm-compactionc-periodically-schedule-when-freeing-pages.patch added to -mm tree
To: rientjes@xxxxxxxxxx,liwanp@xxxxxxxxxxxxxxxxxx,mgorman@xxxxxxx,riel@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 18 Sep 2013 15:34:32 -0700
The patch titled
Subject: mm/compaction.c: periodically schedule when freeing pages
has been added to the -mm tree. Its filename is
mm-compactionc-periodically-schedule-when-freeing-pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-compactionc-periodically-schedule-when-freeing-pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-compactionc-periodically-schedule-when-freeing-pages.patch
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From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm/compaction.c: periodically schedule when freeing pages
We've been getting warnings about an excessive amount of time spent
allocating pages for migration during memory compaction without
scheduling. isolate_freepages_block() already periodically checks for
contended locks or the need to schedule, but isolate_freepages() never
does.
When a zone is massively long and no suitable targets can be found, this
iteration can be quite expensive without ever doing cond_resched().
Check periodically for the need to reschedule while the compaction free
scanner iterates.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Reviewed-by: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 7 +++++++
1 file changed, 7 insertions(+)
diff -puN mm/compaction.c~mm-compactionc-periodically-schedule-when-freeing-pages mm/compaction.c
--- a/mm/compaction.c~mm-compactionc-periodically-schedule-when-freeing-pages
+++ a/mm/compaction.c
@@ -677,6 +677,13 @@ static void isolate_freepages(struct zon
pfn -= pageblock_nr_pages) {
unsigned long isolated;
+ /*
+ * This can iterate a massively long zone without finding any
+ * suitable migration targets, so periodically check if we need
+ * to schedule.
+ */
+ cond_resched();
+
if (!pfn_valid(pfn))
continue;
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-compactionc-periodically-schedule-when-freeing-pages.patch
mm-acpi-use-numa_no_node.patch
x86-srat-use-numa_no_node.patch
mm-vmalloc-use-numa_no_node.patch
mm-vmalloc-dont-set-area-caller-twice.patch
mm-vmalloc-revert-mm-vmallocc-emit-the-failure-message-before-return.patch
mm-vmalloc-revert-mm-vmallocc-check-vm_uninitialized-flag-in-s_show-instead-of-show_numa_info.patch
mm-vmalloc-fix-show-vmap_area-information-race-with-vmap_area-tear-down.patch
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