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authorMel Gorman <mel@csn.ul.ie>2010-08-09 17:19:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-09 20:45:00 -0700
commit755f0225e8347b23a33ee6e3fb14a35310f95766 (patch)
tree23489e9f52f1435c7b8bc4da8e98d607460e4e23 /mm/vmscan.c
parenta8a94d151521b248727c1f88756174e15260815a (diff)
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vmscan: tracing: add trace event when a page is written
Add a trace event for when page reclaim queues a page for IO and records whether it is synchronous or asynchronous. Excessive synchronous IO for a process can result in noticeable stalls during direct reclaim. Excessive IO from page reclaim may indicate that the system is seriously under provisioned for the amount of dirty pages that exist. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Larry Woodman <lwoodman@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michael Rubin <mrubin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmscan.c')
-rw-r--r--mm/vmscan.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 3d006d91a52..b7a4e6a3cf8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -401,6 +401,8 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
/* synchronous write or broken a_ops? */
ClearPageReclaim(page);
}
+ trace_mm_vmscan_writepage(page,
+ trace_reclaim_flags(page, sync_writeback));
inc_zone_page_state(page, NR_VMSCAN_WRITE);
return PAGE_SUCCESS;
}