linux-kernel - [PATCH v3 2/9] mm/page_owner: initialize page owner without holding the zone lock

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Date:	Fri, 17 Jun 2016 16:57:32 +0900
From:	js1304@...il.com
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Vlastimil Babka <vbabka@...e.cz>, mgorman@...hsingularity.net,
	Minchan Kim <minchan@...nel.org>,
	Alexander Potapenko <glider@...gle.com>,
	Hugh Dickins <hughd@...gle.com>,
	Michal Hocko <mhocko@...nel.org>, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, Sasha Levin <sasha.levin@...cle.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH v3 2/9] mm/page_owner: initialize page owner without holding the zone lock

From: Joonsoo Kim <iamjoonsoo.kim@....com>

It's not necessary to initialized page_owner with holding the zone lock.
It would cause more contention on the zone lock although it's not a big
problem since it is just debug feature.  But, it is better than before so
do it.  This is also preparation step to use stackdepot in page owner
feature.  Stackdepot allocates new pages when there is no reserved space
and holding the zone lock in this case will cause deadlock.

Link: http://lkml.kernel.org/r/1464230275-25791-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Cc: Mel Gorman <mgorman@...hsingularity.net>
Cc: Minchan Kim <minchan@...nel.org>
Cc: Alexander Potapenko <glider@...gle.com>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Michal Hocko <mhocko@...nel.org>
---
 mm/compaction.c     | 3 +++
 mm/page_alloc.c     | 2 --
 mm/page_isolation.c | 9 ++++++---
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 5557421..942d6cd 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -19,6 +19,7 @@
 #include <linux/kasan.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
+#include <linux/page_owner.h>
 #include "internal.h"
 
 #ifdef CONFIG_COMPACTION
@@ -79,6 +80,8 @@ static void map_pages(struct list_head *list)
 		arch_alloc_page(page, order);
 		kernel_map_pages(page, nr_pages, 1);
 		kasan_alloc_pages(page, order);
+
+		set_page_owner(page, order, __GFP_MOVABLE);
 		if (order)
 			split_page(page, order);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e07f424..127128a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2514,8 +2514,6 @@ int __isolate_free_page(struct page *page, unsigned int order)
 	zone->free_area[order].nr_free--;
 	rmv_page_order(page);
 
-	set_page_owner(page, order, __GFP_MOVABLE);
-
 	/* Set the pageblock if the isolated page is at least a pageblock */
 	if (order >= pageblock_order - 1) {
 		struct page *endpage = page + (1 << order) - 1;
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 612122b..927f5ee 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -7,6 +7,7 @@
 #include <linux/pageblock-flags.h>
 #include <linux/memory.h>
 #include <linux/hugetlb.h>
+#include <linux/page_owner.h>
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
@@ -108,8 +109,6 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 			if (pfn_valid_within(page_to_pfn(buddy)) &&
 			    !is_migrate_isolate_page(buddy)) {
 				__isolate_free_page(page, order);
-				kernel_map_pages(page, (1 << order), 1);
-				set_page_refcounted(page);
 				isolated_page = page;
 			}
 		}
@@ -128,8 +127,12 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 	zone->nr_isolate_pageblock--;
 out:
 	spin_unlock_irqrestore(&zone->lock, flags);
-	if (isolated_page)
+	if (isolated_page) {
+		kernel_map_pages(page, (1 << order), 1);
+		set_page_refcounted(page);
+		set_page_owner(page, order, __GFP_MOVABLE);
 		__free_pages(isolated_page, order);
+	}
 }
 
 static inline struct page *
-- 
1.9.1