We promote sc->gfp_mask to __GFP_HIGHMEM to forcibly scan highmem if there are too many buffer_heads pinning highmem. see: cc715d99e5 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@xxxxxxxxxxx> --- Changes since v1: - use orig_mask to record the caller's orininal mask and restore it after finishing scan, according to Riel's suggestion. V1: https://lkml.org/lkml/2014/2/12/764 mm/vmscan.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index a9c74b4..da0a87c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2298,6 +2298,7 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc) unsigned long nr_soft_reclaimed; unsigned long nr_soft_scanned; bool aborted_reclaim = false; + gfp_t orig_mask = sc->gfp_mask; /* * If the number of buffer_heads in the machine exceeds the maximum @@ -2354,6 +2355,12 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc) shrink_zone(zone, sc); } + /* + * restore to original mask to avoid the impact on its caller + * if we promote it to __GFP_HIGHMEM. + */ + sc->gfp_mask = orig_mask; + return aborted_reclaim; } -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>