linux-kernel - [PATCH 14/34] mm: zone_reclaim: make isolate_lru

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1343050727-3045-15-git-send-email-mgorman@suse.de>
Date:	Mon, 23 Jul 2012 14:38:27 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Stable <stable@...r.kernel.org>
Cc:	Linux-MM <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>,
	Mel Gorman <mgorman@...e.de>
Subject: [PATCH 14/34] mm: zone_reclaim: make isolate_lru_page() filter-aware

From: Minchan Kim <minchan.kim@...il.com>

commit f80c0673610e36ae29d63e3297175e22f70dde5f upstream.

Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list
	leading to poor reclaim decisions which has a variable performance
	impact.

In __zone_reclaim case, we don't want to shrink mapped page.  Nonetheless,
we have isolated mapped page and re-add it into LRU's head.  It's
unnecessary CPU overhead and makes LRU churning.

Of course, when we isolate the page, the page might be mapped but when we
try to migrate the page, the page would be not mapped.  So it could be
migrated.  But race is rare and although it happens, it's no big deal.

Signed-off-by: Minchan Kim <minchan.kim@...il.com>
Acked-by: Johannes Weiner <hannes@...xchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@...e.cz>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Rik van Riel <riel@...hat.com>
Cc: Andrea Arcangeli <aarcange@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@...e.de>
---
 include/linux/mmzone.h |    2 ++
 mm/vmscan.c            |   20 ++++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 632107e..951ed81 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -164,6 +164,8 @@ static inline int is_unevictable_lru(enum lru_list l)
 #define ISOLATE_ACTIVE		((__force isolate_mode_t)0x2)
 /* Isolate clean file */
 #define ISOLATE_CLEAN		((__force isolate_mode_t)0x4)
+/* Isolate unmapped file */
+#define ISOLATE_UNMAPPED	((__force isolate_mode_t)0x8)
 
 /* LRU Isolation modes. */
 typedef unsigned __bitwise__ isolate_mode_t;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 032f35e..9aa75e9 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1048,6 +1048,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
 	if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page)))
 		return ret;
 
+	if ((mode & ISOLATE_UNMAPPED) && page_mapped(page))
+		return ret;
+
 	if (likely(get_page_unless_zero(page))) {
 		/*
 		 * Be careful not to clear PageLRU until after we're
@@ -1471,6 +1474,12 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
 		reclaim_mode |= ISOLATE_ACTIVE;
 
 	lru_add_drain();
+
+	if (!sc->may_unmap)
+		reclaim_mode |= ISOLATE_UNMAPPED;
+	if (!sc->may_writepage)
+		reclaim_mode |= ISOLATE_CLEAN;
+
 	spin_lock_irq(&zone->lru_lock);
 
 	if (scanning_global_lru(sc)) {
@@ -1588,19 +1597,26 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
 	struct page *page;
 	struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 	unsigned long nr_rotated = 0;
+	isolate_mode_t reclaim_mode = ISOLATE_ACTIVE;
 
 	lru_add_drain();
+
+	if (!sc->may_unmap)
+		reclaim_mode |= ISOLATE_UNMAPPED;
+	if (!sc->may_writepage)
+		reclaim_mode |= ISOLATE_CLEAN;
+
 	spin_lock_irq(&zone->lru_lock);
 	if (scanning_global_lru(sc)) {
 		nr_taken = isolate_pages_global(nr_pages, &l_hold,
 						&pgscanned, sc->order,
-						ISOLATE_ACTIVE, zone,
+						reclaim_mode, zone,
 						1, file);
 		zone->pages_scanned += pgscanned;
 	} else {
 		nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold,
 						&pgscanned, sc->order,
-						ISOLATE_ACTIVE, zone,
+						reclaim_mode, zone,
 						sc->mem_cgroup, 1, file);
 		/*
 		 * mem_cgroup_isolate_pages() keeps track of
-- 
1.7.9.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/