The patch titled
Subject: mm, compaction: don't recheck watermarks after COMPACT_SUCCESS
has been added to the -mm tree. Its filename is
mm-compaction-dont-recheck-watermarks-after-compact_success.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-compaction-dont-recheck-watermarks-after-compact_success.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-compaction-dont-recheck-watermarks-after-compact_success.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, compaction: don't recheck watermarks after COMPACT_SUCCESS
Joonsoo has reminded me that in a later patch changing watermark checks
throughout compaction I forgot to update checks in try_to_compact_pages()
and compactd_do_work(). Closer inspection however shows that they are
redundant now that compact_zone() reliably reports success with
COMPACT_SUCCESS, as they just repeat (a subset) of checks that have just
passed. So instead of checking watermarks again, just test the return
value.
Also remove the stray "bool success" variable from kcompactd_do_work().
Link: http://lkml.kernel.org/r/20160810091226.6709-5-vbabka@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Reported-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff -puN mm/compaction.c~mm-compaction-dont-recheck-watermarks-after-compact_success mm/compaction.c
--- a/mm/compaction.c~mm-compaction-dont-recheck-watermarks-after-compact_success
+++ a/mm/compaction.c
@@ -1698,9 +1698,8 @@ enum compact_result try_to_compact_pages
alloc_flags, ac_classzone_idx(ac));
rc = max(status, rc);
- /* If a normal allocation would succeed, stop compacting */
- if (zone_watermark_ok(zone, order, low_wmark_pages(zone),
- ac_classzone_idx(ac), alloc_flags)) {
+ /* The allocation should succeed, stop compacting */
+ if (status == COMPACT_SUCCESS) {
/*
* We think the allocation will succeed in this zone,
* but it is not certain, hence the false. The caller
@@ -1873,8 +1872,6 @@ static void kcompactd_do_work(pg_data_t
.ignore_skip_hint = true,
};
- bool success = false;
-
trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,
cc.classzone_idx);
count_vm_event(KCOMPACTD_WAKE);
@@ -1903,9 +1900,7 @@ static void kcompactd_do_work(pg_data_t
return;
status = compact_zone(zone, &cc);
- if (zone_watermark_ok(zone, cc.order, low_wmark_pages(zone),
- cc.classzone_idx, 0)) {
- success = true;
+ if (status == COMPACT_SUCCESS) {
compaction_defer_reset(zone, cc.order, false);
} else if (status == COMPACT_PARTIAL_SKIPPED || status == COMPACT_COMPLETE) {
/*
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-compaction-make-whole_zone-flag-ignore-cached-scanner-positions.patch
mm-compaction-cleanup-unused-functions.patch
mm-compaction-rename-compact_partial-to-compact_success.patch
mm-compaction-dont-recheck-watermarks-after-compact_success.patch
mm-compaction-add-the-ultimate-direct-compaction-priority.patch
mm-compaction-more-reliably-increase-direct-compaction-priority.patch
mm-compaction-use-correct-watermark-when-checking-compaction-success.patch
mm-compaction-create-compact_gap-wrapper.patch
mm-compaction-use-proper-alloc_flags-in-__compaction_suitable.patch
mm-compaction-require-only-min-watermarks-for-non-costly-orders.patch
mm-vmscan-make-compaction_ready-more-accurate-and-readable.patch
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