Commit 6cd9dc3e authored May 20, 2016 by Chen Feng Committed by Linus Torvalds May 20, 2016

mm/compaction.c: fix zoneindex in kcompactd()

While testing the kcompactd in my platform 3G MEM only DMA ZONE.  I
found the kcompactd never wakeup.  It seems the zoneindex has already
minus 1 before.  So the traverse here should be <=.

It fixes a regression where kswapd could previously compact, but
kcompactd not.  Not a crash fix though.

[akpm@linux-foundation.org: fix kcompactd_do_work() as well, per Hugh]
Link: http://lkml.kernel.org/r/1463659121-84124-1-git-send-email-puck.chen@hisilicon.com


Fixes: accf6242 ("mm, kswapd: replace kswapd compaction with waking up kcompactd")
Signed-off-by: Chen Feng <puck.chen@hisilicon.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhuangluan Su <suzhuangluan@hisilicon.com>
Cc: Yiping Xu <xuyiping@hisilicon.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 0bb2fd13

mm/compaction.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1862,7 +1862,7 @@ static bool kcompactd_node_suitable(pg_data_t *pgdat)
		struct zone *zone;
		enum zone_type classzone_idx = pgdat->kcompactd_classzone_idx;

		for (zoneid = 0; zoneid < classzone_idx; zoneid++) {
		for (zoneid = 0; zoneid <= classzone_idx; zoneid++) {
		zone = &pgdat->node_zones[zoneid];

		if (!populated_zone(zone))
		@@ -1897,7 +1897,7 @@ static void kcompactd_do_work(pg_data_t *pgdat)
		cc.classzone_idx);
		count_vm_event(KCOMPACTD_WAKE);

		for (zoneid = 0; zoneid < cc.classzone_idx; zoneid++) {
		for (zoneid = 0; zoneid <= cc.classzone_idx; zoneid++) {
		int status;

		zone = &pgdat->node_zones[zoneid];

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