mm/vmscan: restore sc->gfp_mask after promoting it to __GFP_HIGHMEM
We promote sc->gfp_mask to __GFP_HIGHMEM to forcibly scan highmem if
there are too many buffer_heads pinning highmem. See cc715d99e5 ("mm:
vmscan: forcibly scan highmem if there are too many buffer_heads pinning
highmem").
This patch restores sc->gfp_mask to its caller original value after
finishing the scan job, to avoid the impact on other invocations from
its upper caller, such as vmpressure_prio(), shrink_slab().
Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1f56a80..1c51e4f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2314,6 +2314,7 @@
unsigned long lru_pages = 0;
bool aborted_reclaim = false;
struct reclaim_state *reclaim_state = current->reclaim_state;
+ gfp_t orig_mask;
struct shrink_control shrink = {
.gfp_mask = sc->gfp_mask,
};
@@ -2323,6 +2324,7 @@
* allowed level, force direct reclaim to scan the highmem zone as
* highmem pages could be pinning lowmem pages storing buffer_heads
*/
+ orig_mask = sc->gfp_mask;
if (buffer_heads_over_limit)
sc->gfp_mask |= __GFP_HIGHMEM;
@@ -2393,6 +2395,12 @@
}
}
+ /*
+ * Restore to original mask to avoid the impact on the caller if we
+ * promoted it to __GFP_HIGHMEM.
+ */
+ sc->gfp_mask = orig_mask;
+
return aborted_reclaim;
}