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From: Ganesh Mahendran <opensource.ganesh@gmail.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: akpm@linux-foundation.org, minchan@kernel.org, ngupta@vflare.org,
	sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org,
	mingo@redhat.com, Ganesh Mahendran <opensource.ganesh@gmail.com>
Subject: [PATCH v3 4/8] mm/zsmalloc: avoid calculate max objects of zspage twice
Date: Wed,  6 Jul 2016 14:23:49 +0800	[thread overview]
Message-ID: <1467786233-4481-4-git-send-email-opensource.ganesh@gmail.com> (raw)
In-Reply-To: <1467786233-4481-1-git-send-email-opensource.ganesh@gmail.com>

Currently, if a class can not be merged, the max objects of zspage
in that class may be calculated twice.

This patch calculate max objects of zspage at the begin, and pass
the value to can_merge() to decide whether the class can be merged.

Also this patch remove function get_maxobj_per_zspage(), as there
is no other place to call this function.

Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
----
v3:
    none
v2:
    remove get_maxobj_per_zspage()  - Minchan
---
 mm/zsmalloc.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 82ff2c0..82b9977 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -470,11 +470,6 @@ static struct zpool_driver zs_zpool_driver = {
 MODULE_ALIAS("zpool-zsmalloc");
 #endif /* CONFIG_ZPOOL */
 
-static unsigned int get_maxobj_per_zspage(int size, int pages_per_zspage)
-{
-	return pages_per_zspage * PAGE_SIZE / size;
-}
-
 /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
 static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
 
@@ -1362,16 +1357,14 @@ static void init_zs_size_classes(void)
 	zs_size_classes = nr;
 }
 
-static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
+static bool can_merge(struct size_class *prev, int pages_per_zspage,
+					int objs_per_zspage)
 {
-	if (prev->pages_per_zspage != pages_per_zspage)
-		return false;
+	if (prev->pages_per_zspage == pages_per_zspage &&
+		prev->objs_per_zspage == objs_per_zspage)
+		return true;
 
-	if (prev->objs_per_zspage
-		!= get_maxobj_per_zspage(size, pages_per_zspage))
-		return false;
-
-	return true;
+	return false;
 }
 
 static bool zspage_full(struct size_class *class, struct zspage *zspage)
@@ -2448,6 +2441,7 @@ struct zs_pool *zs_create_pool(const char *name)
 	for (i = zs_size_classes - 1; i >= 0; i--) {
 		int size;
 		int pages_per_zspage;
+		int objs_per_zspage;
 		struct size_class *class;
 		int fullness = 0;
 
@@ -2455,6 +2449,7 @@ struct zs_pool *zs_create_pool(const char *name)
 		if (size > ZS_MAX_ALLOC_SIZE)
 			size = ZS_MAX_ALLOC_SIZE;
 		pages_per_zspage = get_pages_per_zspage(size);
+		objs_per_zspage = pages_per_zspage * PAGE_SIZE / size;
 
 		/*
 		 * size_class is used for normal zsmalloc operation such
@@ -2466,7 +2461,7 @@ struct zs_pool *zs_create_pool(const char *name)
 		 * previous size_class if possible.
 		 */
 		if (prev_class) {
-			if (can_merge(prev_class, size, pages_per_zspage)) {
+			if (can_merge(prev_class, pages_per_zspage, objs_per_zspage)) {
 				pool->size_class[i] = prev_class;
 				continue;
 			}
@@ -2479,8 +2474,7 @@ struct zs_pool *zs_create_pool(const char *name)
 		class->size = size;
 		class->index = i;
 		class->pages_per_zspage = pages_per_zspage;
-		class->objs_per_zspage = get_maxobj_per_zspage(class->size,
-							class->pages_per_zspage);
+		class->objs_per_zspage = objs_per_zspage;
 		spin_lock_init(&class->lock);
 		pool->size_class[i] = class;
 		for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
-- 
1.9.1

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  parent reply	other threads:[~2016-07-06  6:26 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-06  6:23 [PATCH v3 1/8] mm/zsmalloc: use obj_index to keep consistent with others Ganesh Mahendran
2016-07-06  6:23 ` [PATCH v3 2/8] mm/zsmalloc: take obj index back from find_alloced_obj Ganesh Mahendran
2016-07-06  6:23 ` [PATCH v3 3/8] mm/zsmalloc: use class->objs_per_zspage to get num of max objects Ganesh Mahendran
2016-07-06  6:23 ` Ganesh Mahendran [this message]
2016-07-06  6:23 ` [PATCH v3 5/8] mm/zsmalloc: keep comments consistent with code Ganesh Mahendran
2016-07-06  6:23 ` [PATCH v3 6/8] mm/zsmalloc: add __init,__exit attribute Ganesh Mahendran
2016-07-06  8:01   ` kbuild test robot
2016-07-06  8:06   ` kbuild test robot
2016-07-06  8:20   ` Ganesh Mahendran
2016-07-06  6:23 ` [PATCH v3 7/8] mm/zsmalloc: use helper to clear page->flags bit Ganesh Mahendran
2016-07-06  6:23 ` [PATCH v3 8/8] mm/zsmalloc: add per-class compact trace event Ganesh Mahendran
2016-07-07  7:44   ` Minchan Kim
2016-07-07  9:08     ` Ganesh Mahendran

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