[Devel] [PATCH rh7] Port diff-mm-vmscan-disable-fs-related-activity-for-direct-direct-reclaim

[Vladimir Davydov]

Author: Dmitry Monakhov
Email: dmonakhov at openvz.org
Subject: mm: disable fs-related activity for direct direct reclaim
Date: Thu, 30 May 2013 18:57:41 +0400

Suggested by alexey at . Avoid various interaction with fs on derect reclaim
in order to avoid possible deadlocks. Let this works for kswapd

https://jira.sw.ru/browse/PSBM-20210

Signed-off-by: Dmitry Monakhov <dmonakhov at openvz.org>
=============================================================================

Related to https://jira.sw.ru/browse/PSBM-33640

Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
---
 mm/vmscan.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index ed0aadeec7f2..836bdb352160 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2232,6 +2232,12 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc,
 {
 	struct reclaim_state *reclaim_state = current->reclaim_state;
 	unsigned long nr_reclaimed, nr_scanned;
+	gfp_t slab_gfp = sc->gfp_mask;
+
+	/* Disable fs-related IO for direct reclaim */
+	if (!sc->target_mem_cgroup &&
+	    (current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)
+		slab_gfp &= ~__GFP_FS;
 
 	do {
 		struct mem_cgroup *root = sc->target_mem_cgroup;
@@ -2260,7 +2266,7 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc,
 			zone_lru_pages += lru_pages;
 
 			if (memcg && is_classzone)
-				shrink_slab(sc->gfp_mask, zone_to_nid(zone),
+				shrink_slab(slab_gfp, zone_to_nid(zone),
 					    memcg, sc->nr_scanned - scanned,
 					    lru_pages);
 
@@ -2286,7 +2292,7 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc,
 		 * the eligible LRU pages were scanned.
 		 */
 		if (global_reclaim(sc) && is_classzone)
-			shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
+			shrink_slab(slab_gfp, zone_to_nid(zone), NULL,
 				    sc->nr_scanned - nr_scanned,
 				    zone_lru_pages);
 
-- 
2.1.4