mm: zone_reclaim: make isolate_lru_page() filter-aware

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@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 0ed9149a2725283381fe30c53f22506bbf08d0cf..80acfbc9aa1462a1e786b5ab1564462c350a8384 100644 (file)
--- 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 68357354db1b86f520647b35d726c5312e2affc6..0c78bd3bd964f037b1f5d5acce73b820103fa9a8 100644 (file)
--- 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