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* [PATCH v2] mm/page_alloc: call check_new_pages() while zone spinlock is not held
@ 2022-03-04 17:02 Eric Dumazet
  2022-03-04 19:19 ` Shakeel Butt
                   ` (3 more replies)
  0 siblings, 4 replies; 17+ messages in thread
From: Eric Dumazet @ 2022-03-04 17:02 UTC (permalink / raw)
  To: Andrew Morton
  Cc: linux-kernel, linux-mm, Eric Dumazet, Eric Dumazet, Mel Gorman,
	Vlastimil Babka, Michal Hocko, Shakeel Butt, Wei Xu, Greg Thelen,
	Hugh Dickins, David Rientjes

From: Eric Dumazet <edumazet@google.com>

For high order pages not using pcp, rmqueue() is currently calling
the costly check_new_pages() while zone spinlock is held,
and hard irqs masked.

This is not needed, we can release the spinlock sooner to reduce
zone spinlock contention.

Note that after this patch, we call __mod_zone_freepage_state()
before deciding to leak the page because it is in bad state.

v2: We need to keep interrupts disabled to call __mod_zone_freepage_state()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
---
 mm/page_alloc.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3589febc6d31928f850ebe5a4015ddc40e0469f3..1804287c1b792b8aa0e964b17eb002b6b1115258 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3706,10 +3706,10 @@ 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 {
 		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
@@ -3721,15 +3721,15 @@ struct page *rmqueue(struct zone *preferred_zone,
 			if (page)
 				trace_mm_page_alloc_zone_locked(page, order, migratetype);
 		}
-		if (!page)
+		if (!page) {
 			page = __rmqueue(zone, order, migratetype, alloc_flags);
-	} while (page && check_new_pages(page, order));
-	if (!page)
-		goto failed;
-
-	__mod_zone_freepage_state(zone, -(1 << order),
-				  get_pcppage_migratetype(page));
-	spin_unlock_irqrestore(&zone->lock, flags);
+			if (!page)
+				goto failed;
+		}
+		__mod_zone_freepage_state(zone, -(1 << order),
+					  get_pcppage_migratetype(page));
+		spin_unlock_irqrestore(&zone->lock, flags);
+	} while (check_new_pages(page, order));
 
 	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
 	zone_statistics(preferred_zone, zone, 1);
-- 
2.35.1.616.g0bdcbb4464-goog


^ permalink raw reply related	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2022-03-14  9:09 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-04 17:02 [PATCH v2] mm/page_alloc: call check_new_pages() while zone spinlock is not held Eric Dumazet
2022-03-04 19:19 ` Shakeel Butt
2022-03-06 22:15 ` David Rientjes
2022-03-07  9:15 ` Mel Gorman
2022-03-08 23:49   ` Eric Dumazet
2022-03-09 12:32     ` Mel Gorman
2022-03-09 17:32       ` Eric Dumazet
2022-03-12 15:43       ` [mm/page_alloc] 8212a964ee: vm-scalability.throughput 30.5% improvement kernel test robot
2022-03-12 18:58         ` Vlastimil Babka
2022-03-12 23:26           ` Eric Dumazet
2022-03-13  9:28             ` Vlastimil Babka
2022-03-13 21:10               ` Eric Dumazet
2022-03-13 21:18                 ` Matthew Wilcox
2022-03-13 21:27                   ` Eric Dumazet
2022-03-13 21:36                     ` Eric Dumazet
2022-03-14  9:09                 ` Vlastimil Babka
2022-03-07  9:24 ` [PATCH v2] mm/page_alloc: call check_new_pages() while zone spinlock is not held Vlastimil Babka

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