mm, vmscan: release/reacquire lru_lock on pgdat change
With node-lru, the locking is based on the pgdat. As Minchan pointed
out, there is an opportunity to reduce LRU lock release/acquire in
check_move_unevictable_pages by only changing lock on a pgdat change.
[mgorman@techsingularity.net: remove double initialisation]
Link: http://lkml.kernel.org/r/20160719074835.GC10438@techsingularity.net
Link: http://lkml.kernel.org/r/1468853426-12858-3-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4978ee9..22aec2b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3774,24 +3774,23 @@
void check_move_unevictable_pages(struct page **pages, int nr_pages)
{
struct lruvec *lruvec;
- struct zone *zone = NULL;
+ struct pglist_data *pgdat = NULL;
int pgscanned = 0;
int pgrescued = 0;
int i;
for (i = 0; i < nr_pages; i++) {
struct page *page = pages[i];
- struct zone *pagezone;
+ struct pglist_data *pagepgdat = page_pgdat(page);
pgscanned++;
- pagezone = page_zone(page);
- if (pagezone != zone) {
- if (zone)
- spin_unlock_irq(zone_lru_lock(zone));
- zone = pagezone;
- spin_lock_irq(zone_lru_lock(zone));
+ if (pagepgdat != pgdat) {
+ if (pgdat)
+ spin_unlock_irq(&pgdat->lru_lock);
+ pgdat = pagepgdat;
+ spin_lock_irq(&pgdat->lru_lock);
}
- lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
+ lruvec = mem_cgroup_page_lruvec(page, pgdat);
if (!PageLRU(page) || !PageUnevictable(page))
continue;
@@ -3807,10 +3806,10 @@
}
}
- if (zone) {
+ if (pgdat) {
__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);
- spin_unlock_irq(zone_lru_lock(zone));
+ spin_unlock_irq(&pgdat->lru_lock);
}
}
#endif /* CONFIG_SHMEM */