Re: [PATCH] low order lumpy reclaim also should use PAGEOUT_IO_SYNC.
From: KOSAKI Motohiro
Date: Wed Apr 22 2009 - 21:21:09 EST
> On Tue, Apr 21, 2009 at 02:22:27PM +0900, KOSAKI Motohiro wrote:
> > Subject: [PATCH] low order lumpy reclaim also should use PAGEOUT_IO_SYNC.
> >
> > commit 33c120ed2843090e2bd316de1588b8bf8b96cbde (more aggressively use lumpy reclaim)
> > change lumpy reclaim using condition. but it isn't enough change.
> >
> > lumpy reclaim don't only mean isolate neighber page, but also do pageout as synchronous.
> > this patch does it.
> >
> > Cc: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
> > Cc: Andy Whitcroft <apw@xxxxxxxxxxxx>
> > Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > Cc: Mel Gorman <mel@xxxxxxxxx>
> > Cc: Rik van Riel <riel@xxxxxxxxxx>
> > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
>
> Seems fair although the changelog could be better. Maybe something like?
>
> ====
>
> Commit 33c120ed2843090e2bd316de1588b8bf8b96cbde increased how aggressive
> lumpy reclaim was by isolating both active and inactive pages for asynchronous
> lumpy reclaim on costly-high-order pages and for cheap-high-order when memory
> pressure is high. However, if the system is under heavy pressure and there
> are dirty pages, asynchronous IO may not be sufficient to reclaim a suitable
> page in time.
>
> This patch causes the caller to enter synchronous lumpy reclaim for
> costly-high-order pages and for cheap-high-order pages when under memory
> pressure.
> ====
>
> Whether the changelog is updated or not though;
>
> Reviewed-by: Mel Gorman <mel@xxxxxxxxx>
Cool!
Andrew, Could you please replace vmscan-low-order-lumpy-reclaim-also-should-use-pageout_io_sync.patch
with following patch?
===================================
Subject: vmscan: low order lumpy reclaim also should use PAGEOUT_IO_SYNC
From: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Commit 33c120ed2843090e2bd316de1588b8bf8b96cbde increased how aggressive
lumpy reclaim was by isolating both active and inactive pages for asynchronous
lumpy reclaim on costly-high-order pages and for cheap-high-order when memory
pressure is high. However, if the system is under heavy pressure and there
are dirty pages, asynchronous IO may not be sufficient to reclaim a suitable
page in time.
This patch causes the caller to enter synchronous lumpy reclaim for
costly-high-order pages and for cheap-high-order pages when under memory
pressure.
Minchan.kim@xxxxxxxxx said:
Andy added synchronous lumpy reclaim with
c661b078fd62abe06fd11fab4ac5e4eeafe26b6d. At that time, lumpy reclaim is
not agressive. His intension is just for high-order users.(above
PAGE_ALLOC_COSTLY_ORDER).
After some time, Rik added aggressive lumpy reclaim with
33c120ed2843090e2bd316de1588b8bf8b96cbde. His intention was to do lumpy
reclaim when high-order users and trouble getting a small set of
contiguous pages.
So we also have to add synchronous pageout for small set of contiguous
pages.
Cc: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
Cc: Andy Whitcroft <apw@xxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: Minchan Kim <Minchan.kim@xxxxxxxxx>
Reviewed-by: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)
diff -puN mm/vmscan.c~vmscan-low-order-lumpy-reclaim-also-should-use-pageout_io_sync mm/vmscan.c
--- a/mm/vmscan.c~vmscan-low-order-lumpy-reclaim-also-should-use-pageout_io_sync
+++ a/mm/vmscan.c
@@ -1059,6 +1059,19 @@ static unsigned long shrink_inactive_lis
unsigned long nr_scanned = 0;
unsigned long nr_reclaimed = 0;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
+ int lumpy_reclaim = 0;
+
+ /*
+ * If we need a large contiguous chunk of memory, or have
+ * trouble getting a small set of contiguous pages, we
+ * will reclaim both active and inactive pages.
+ *
+ * We use the same threshold as pageout congestion_wait below.
+ */
+ if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
+ lumpy_reclaim = 1;
+ else if (sc->order && priority < DEF_PRIORITY - 2)
+ lumpy_reclaim = 1;
pagevec_init(&pvec, 1);
@@ -1071,19 +1084,7 @@ static unsigned long shrink_inactive_lis
unsigned long nr_freed;
unsigned long nr_active;
unsigned int count[NR_LRU_LISTS] = { 0, };
- int mode = ISOLATE_INACTIVE;
-
- /*
- * If we need a large contiguous chunk of memory, or have
- * trouble getting a small set of contiguous pages, we
- * will reclaim both active and inactive pages.
- *
- * We use the same threshold as pageout congestion_wait below.
- */
- if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
- mode = ISOLATE_BOTH;
- else if (sc->order && priority < DEF_PRIORITY - 2)
- mode = ISOLATE_BOTH;
+ int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE;
nr_taken = sc->isolate_pages(sc->swap_cluster_max,
&page_list, &nr_scan, sc->order, mode,
@@ -1120,7 +1121,7 @@ static unsigned long shrink_inactive_lis
* but that should be acceptable to the caller
*/
if (nr_freed < nr_taken && !current_is_kswapd() &&
- sc->order > PAGE_ALLOC_COSTLY_ORDER) {
+ lumpy_reclaim) {
congestion_wait(WRITE, HZ/10);
/*
_
--
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