From df8b5bb998f10cfc040ad30300f9a9ea4592ff82 Mon Sep 17 00:00:00 2001 From: Ganesh Mahendran Date: Fri, 12 Dec 2014 16:57:07 -0800 Subject: [PATCH] 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: Ganesh Mahendran Cc: Minchan Kim Cc: Nitin Gupta Reviewed-by: Dan Streetman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zsmalloc.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 61e180931ca8..2021df5eb891 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -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; -- 2.30.2