mm/vmscan: restore sc->gfp_mask after promoting it to __GFP_HIGHMEM (619d0d76) · Commits · 戴 / test

We promote sc->gfp_mask to __GFP_HIGHMEM to forcibly scan highmem if there are too many buffer_heads pinning highmem. See ("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>

mm/vmscan.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -2314,6 +2314,7 @@ static bool shrink_zones(struct zonelist zonelist, struct scan_control sc)
		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 @@ static bool shrink_zones(struct zonelist zonelist, struct scan_control sc)
		* 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 @@ static bool shrink_zones(struct zonelist zonelist, struct scan_control sc)
		}
		}

		/*
		* 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;
		}

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