Author: Andy Whitcroft <[EMAIL PROTECTED]>
AuthorDate: Wed Aug 22 14:01:25 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Aug 22 19:52:45 2007 -0700
synchronous lumpy reclaim: ensure we count pages transitioning inactive via
As pointed out by Mel when reclaim is applied at higher orders a significant
amount of IO may be started. As this takes finite time to drain reclaim
consider more areas than ultimatly needed to satisfy the request. This
to more reclaim than strictly required and reduced success rates.
I was able to confirm Mel's test results on systems locally. These show
even under light load the success rates drop off far more than expected.
Testing with a modified version of his patch (which follows) I was able to
allocate almost all of ZONE_MOVABLE with a near idle system. I ran 5 test
passes sequentially following system boot (the system has 29 hugepages in
2.6.23-rc1 11 8 6 7 7
sync_lumpy 28 28 29 29 26
These show that although hugely better than the near 0% success normally
expected we can only allocate about a 1/4 of the zone. Using synchronous
reclaim for these allocations we get close to 100% as expected.
I have also run our standard high order tests and these show no regressions
allocation success rates at rest, and some significant improvements under
We are transitioning pages from active to inactive in clear_active_flags,
those need counting as PGDEACTIVATE vm events.
Signed-off-by: Andy Whitcroft <[EMAIL PROTECTED]>
Acked-by: Mel Gorman <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
mm/vmscan.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index d419e10..99ec7fa 100644
@@ -777,6 +777,7 @@ static unsigned long shrink_inactive_list(unsigned long
(sc->order > PAGE_ALLOC_COSTLY_ORDER)?
ISOLATE_BOTH : ISOLATE_INACTIVE);
nr_active = clear_active_flags(&page_list);
+ __count_vm_events(PGDEACTIVATE, nr_active);
__mod_zone_page_state(zone, NR_ACTIVE, -nr_active);
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