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Subject[PATCH V2 2/2] mm/vmscan: not check compaction_ready on promoted zones
We abort direct reclaim if find the zone is ready for compaction.
Sometimes the zone is just a promoted highmem zone to force scan
pinning highmem, which is not the intended zone the caller want to
alloc page from. In this situation, setting aborted_reclaim to
indicate the caller turn back to retry allocation is waste of time
and could cause a loop in __alloc_pages_slowpath().

This patch do not check compaction_ready() on promoted zones to avoid
the above situation, only set aborted_reclaim if the caller intended
zone is ready to compaction.

Acked-by: Rik van Riel <>
Signed-off-by: Weijie Yang <>
mm/vmscan.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index da0a87c..9ec6519 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2299,6 +2299,7 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
unsigned long nr_soft_scanned;
bool aborted_reclaim = false;
gfp_t orig_mask = sc->gfp_mask;
+ enum zone_type requested_highidx = gfp_zone(sc->gfp_mask);

* If the number of buffer_heads in the machine exceeds the maximum
@@ -2332,7 +2333,8 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
* noticeable problem, like transparent huge
* page allocations.
- if (compaction_ready(zone, sc)) {
+ if ((zonelist_zone_idx(z) <= requested_highidx)
+ && compaction_ready(zone, sc)) {
aborted_reclaim = true;

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