Commit df8b5bb9 authored by Ganesh Mahendran's avatar Ganesh Mahendran Committed by Linus Torvalds
Browse files

mm/zsmalloc: avoid duplicate assignment of prev_class 



In zs_create_pool(), prev_class is assigned (ZS_SIZE_CLASSES - 1) times.
And the prev_class only references to the previous size_class.  So we do
not need unnecessary assignement.

This patch assigns *prev_class* when a new size_class structure is
allocated and uses prev_class to check whether the first class has been
allocated.

[akpm@linux-foundation.org: remove now-unused ZS_SIZE_CLASSES]
Signed-off-by: default avatarGanesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Reviewed-by: default avatarDan Streetman <ddstreet@ieee.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d49b1c25

mm/zsmalloc.c

+4 −5
Original line number Diff line number Diff line
@@ -155,8 +155,6 @@ 
 *  (reason above)

 */

#define ZS_SIZE_CLASS_DELTA	(PAGE_SIZE >> 8)

#define ZS_SIZE_CLASSES		((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / \

					ZS_SIZE_CLASS_DELTA + 1)



/*

 * We do not maintain any list for completely empty or full pages
@@ -983,6 +981,7 @@ struct zs_pool *zs_create_pool(gfp_t flags) 
{

	int i, ovhd_size;

	struct zs_pool *pool;

	struct size_class *prev_class = NULL;



	ovhd_size = roundup(sizeof(*pool), PAGE_SIZE);

	pool = kzalloc(ovhd_size, GFP_KERNEL);
@@ -1004,7 +1003,6 @@ struct zs_pool *zs_create_pool(gfp_t flags) 
		int size;

		int pages_per_zspage;

		struct size_class *class;

		struct size_class *prev_class;



		size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;

		if (size > ZS_MAX_ALLOC_SIZE)
@@ -1020,8 +1018,7 @@ struct zs_pool *zs_create_pool(gfp_t flags) 
		 * characteristics. So, we makes size_class point to

		 * previous size_class if possible.

		 */

		if (i < ZS_SIZE_CLASSES - 1) {

			prev_class = pool->size_class[i + 1];

		if (prev_class) {

			if (can_merge(prev_class, size, pages_per_zspage)) {

				pool->size_class[i] = prev_class;

				continue;
@@ -1037,6 +1034,8 @@ struct zs_pool *zs_create_pool(gfp_t flags) 
		class->pages_per_zspage = pages_per_zspage;

		spin_lock_init(&class->lock);

		pool->size_class[i] = class;



		prev_class = class;

	}



	pool->flags = flags;

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