From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754902AbdGUWo6 (ORCPT ); Fri, 21 Jul 2017 18:44:58 -0400 Received: from mga06.intel.com ([134.134.136.31]:24189 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754845AbdGUWo4 (ORCPT ); Fri, 21 Jul 2017 18:44:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,392,1496127600"; d="scan'208";a="129672789" From: Tim Chen To: Andrew Morton Cc: Tim Chen , Ying Huang , Wenwei Tao , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Minchan Kim , Rik van Riel , Andrea Arcangeli , Johannes Weiner , Michal Hocko , Hillf Danton Subject: [PATCH 2/2] mm/swap: Remove lock_initialized flag from swap_slots_cache Date: Fri, 21 Jul 2017 15:45:01 -0700 Message-Id: <867d1fb070644e6d5f0ac7780f63e75259b82cc3.1500677066.git.tim.c.chen@linux.intel.com> X-Mailer: git-send-email 2.9.4 In-Reply-To: <65a9d0f133f63e66bba37b53b2fd0464b7cae771.1500677066.git.tim.c.chen@linux.intel.com> References: <65a9d0f133f63e66bba37b53b2fd0464b7cae771.1500677066.git.tim.c.chen@linux.intel.com> In-Reply-To: <65a9d0f133f63e66bba37b53b2fd0464b7cae771.1500677066.git.tim.c.chen@linux.intel.com> References: <65a9d0f133f63e66bba37b53b2fd0464b7cae771.1500677066.git.tim.c.chen@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We will only reach the lock initialization code in alloc_swap_slot_cache when the cpu's swap_slots_cache's slots have not been allocated and swap_slots_cache has not been initialized previously. So the lock_initialized check is redundant and unnecessary. Remove lock_initialized flag from swap_slots_cache to save memory. Reported-by: Wenwei Tao Signed-off-by: Tim Chen --- include/linux/swap_slots.h | 1 - mm/swap_slots.c | 9 ++++----- 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/include/linux/swap_slots.h b/include/linux/swap_slots.h index 6ef92d1..a75c30b 100644 --- a/include/linux/swap_slots.h +++ b/include/linux/swap_slots.h @@ -10,7 +10,6 @@ #define THRESHOLD_DEACTIVATE_SWAP_SLOTS_CACHE (2*SWAP_SLOTS_CACHE_SIZE) struct swap_slots_cache { - bool lock_initialized; struct mutex alloc_lock; /* protects slots, nr, cur */ swp_entry_t *slots; int nr; diff --git a/mm/swap_slots.c b/mm/swap_slots.c index 4c5457c..c039e6c 100644 --- a/mm/swap_slots.c +++ b/mm/swap_slots.c @@ -140,11 +140,10 @@ static int alloc_swap_slot_cache(unsigned int cpu) if (cache->slots || cache->slots_ret) /* cache already allocated */ goto out; - if (!cache->lock_initialized) { - mutex_init(&cache->alloc_lock); - spin_lock_init(&cache->free_lock); - cache->lock_initialized = true; - } + + mutex_init(&cache->alloc_lock); + spin_lock_init(&cache->free_lock); + cache->nr = 0; cache->cur = 0; cache->n_ret = 0; -- 2.9.4