From: Eric Dumazet <edumazet@xxxxxxxxxx>
For high order pages not using pcp, rmqueue() is currently calling
the costly check_new_pages() while zone spinlock is held.
This is not needed, we can release the spinlock sooner to reduce
zone spinlock contention.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/page_alloc.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3589febc6d31928f850ebe5a4015ddc40e0469f3..0890a65f8cc2259e82bc1f5ba95a592fb30f9fb8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3685,7 +3685,6 @@ struct page *rmqueue(struct zone *preferred_zone,
gfp_t gfp_flags, unsigned int alloc_flags,
int migratetype)
{
- unsigned long flags;
struct page *page;
if (likely(pcp_allowed_order(order))) {
@@ -3706,10 +3705,12 @@ struct page *rmqueue(struct zone *preferred_zone,
* allocate greater than order-1 page units with __GFP_NOFAIL.
*/
WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
- spin_lock_irqsave(&zone->lock, flags);
do {
+ unsigned long flags;
+
page = NULL;
+ spin_lock_irqsave(&zone->lock, flags);
/*
* order-0 request can reach here when the pcplist is skipped
* due to non-CMA allocation context. HIGHATOMIC area is
@@ -3723,13 +3724,13 @@ struct page *rmqueue(struct zone *preferred_zone,
}
if (!page)
page = __rmqueue(zone, order, migratetype, alloc_flags);
- } while (page && check_new_pages(page, order));
- if (!page)
- goto failed;
+ spin_unlock_irqrestore(&zone->lock, flags);
+ if (!page)
+ return NULL;
+ } while (check_new_pages(page, order));
__mod_zone_freepage_state(zone, -(1 << order),
get_pcppage_migratetype(page));
- spin_unlock_irqrestore(&zone->lock, flags);
__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
zone_statistics(preferred_zone, zone, 1);
@@ -3743,10 +3744,6 @@ struct page *rmqueue(struct zone *preferred_zone,
VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
return page;
-
-failed:
- spin_unlock_irqrestore(&zone->lock, flags);
- return NULL;
}
#ifdef CONFIG_FAIL_PAGE_ALLOC
--
2.35.1.616.g0bdcbb4464-goog
