Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754049AbaKYNBD (ORCPT ); Tue, 25 Nov 2014 08:01:03 -0500 Received: from mail-pd0-f171.google.com ([209.85.192.171]:51443 "EHLO mail-pd0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752259AbaKYNBA (ORCPT ); Tue, 25 Nov 2014 08:01:00 -0500 From: Ganesh Mahendran To: minchan@kernel.org, ngupta@vflare.org, ddstreet@ieee.org Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ganesh Mahendran Subject: [PATCH v3] mm/zsmalloc: avoid duplicate assignment of prev_class Date: Tue, 25 Nov 2014 21:00:44 +0800 Message-Id: <1416920444-4181-1-git-send-email-opensource.ganesh@gmail.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Ganesh Mahendran Cc: Minchan Kim Cc: Nitin Gupta Cc: Dan Streetman --- v1 -> v2: - follow Dan Streetman's advise to use prev_class to check whether the first class has been allocated - follow Minchan Kim's advise to remove uninitialized_var() v2 -> v3: - move *prev_class* definition out of the loop - Dan --- mm/zsmalloc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 83ecdb6..de1320e 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -966,6 +966,7 @@ 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); @@ -980,7 +981,6 @@ 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) @@ -996,8 +996,7 @@ 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; @@ -1013,6 +1012,8 @@ 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; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/