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Commit 64d90465 authored by Ganesh Mahendran's avatar Ganesh Mahendran Committed by Linus Torvalds
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mm/zsmalloc: avoid calculate max objects of zspage twice 

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.

Link: http://lkml.kernel.org/r/1467882338-4300-4-git-send-email-opensource.ganesh@gmail.com


Signed-off-by: default avatarGanesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b4fd07a0

mm/zsmalloc.c

+10 −16
Original line number Diff line number Diff line
@@ -467,11 +467,6 @@ 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);
@@ -1359,16 +1354,14 @@ 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;

}



static bool zspage_full(struct size_class *class, struct zspage *zspage)
@@ -2438,6 +2431,7 @@ 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;
@@ -2445,6 +2439,7 @@ 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
@@ -2456,7 +2451,7 @@ 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;

			}
@@ -2469,8 +2464,7 @@ 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;