linux-kernel - [PATCH v4 2/8] mm/zsmalloc: take obj index back from find_alloced

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Date:	Thu,  7 Jul 2016 17:05:32 +0800
From:	Ganesh Mahendran <opensource.ganesh@...il.com>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:	akpm@...ux-foundation.org, minchan@...nel.org, ngupta@...are.org,
	sergey.senozhatsky.work@...il.com, mingo@...hat.com,
	rostedt@...dmis.org, Ganesh Mahendran <opensource.ganesh@...il.com>
Subject: [PATCH v4 2/8] mm/zsmalloc: take obj index back from find_alloced_obj

the obj index value should be updated after return from
find_alloced_obj() to avoid CPU burning caused by unnecessary
object scanning.

Signed-off-by: Ganesh Mahendran <opensource.ganesh@...il.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Acked-by: Minchan Kim <minchan@...nel.org>
----
v4: none
v3: none
v2:
  - update commit description
---
 mm/zsmalloc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 3a37977..1f144f1 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1744,10 +1744,11 @@ static void zs_object_copy(struct size_class *class, unsigned long dst,
  * return handle.
  */
 static unsigned long find_alloced_obj(struct size_class *class,
-					struct page *page, int index)
+					struct page *page, int *obj_idx)
 {
 	unsigned long head;
 	int offset = 0;
+	int index = *obj_idx;
 	unsigned long handle = 0;
 	void *addr = kmap_atomic(page);
 
@@ -1768,6 +1769,9 @@ static unsigned long find_alloced_obj(struct size_class *class,
 	}
 
 	kunmap_atomic(addr);
+
+	*obj_idx = index;
+
 	return handle;
 }
 
@@ -1793,7 +1797,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
 	int ret = 0;
 
 	while (1) {
-		handle = find_alloced_obj(class, s_page, obj_idx);
+		handle = find_alloced_obj(class, s_page, &obj_idx);
 		if (!handle) {
 			s_page = get_next_page(s_page);
 			if (!s_page)
-- 
1.9.1