From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id E10246B0005 for ; Fri, 20 Jul 2018 03:19:58 -0400 (EDT) Received: by mail-pg1-f199.google.com with SMTP id e19-v6so5341730pgv.11 for ; Fri, 20 Jul 2018 00:19:58 -0700 (PDT) Received: from mga03.intel.com (mga03.intel.com. [134.134.136.65]) by mx.google.com with ESMTPS id q90-v6si1235046pfa.272.2018.07.20.00.19.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Jul 2018 00:19:56 -0700 (PDT) From: Huang Ying Subject: [PATCH v4 1/8] swap: Add comments to lock_cluster_or_swap_info() Date: Fri, 20 Jul 2018 15:18:38 +0800 Message-Id: <20180720071845.17920-2-ying.huang@intel.com> In-Reply-To: <20180720071845.17920-1-ying.huang@intel.com> References: <20180720071845.17920-1-ying.huang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Michal Hocko , Johannes Weiner , Shaohua Li , Hugh Dickins , Minchan Kim , Rik van Riel , Dan Williams , Dave Hansen , Daniel Jordan To improve the code readability. Signed-off-by: "Huang, Ying" Suggested-and-acked-by: Dave Hansen Reviewed-by: Daniel Jordan Cc: Michal Hocko Cc: Johannes Weiner Cc: Shaohua Li Cc: Hugh Dickins Cc: Minchan Kim Cc: Rik van Riel Cc: Dan Williams --- mm/swapfile.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index d8fddfb000ec..d101e044efbf 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -297,13 +297,18 @@ static inline void unlock_cluster(struct swap_cluster_info *ci) spin_unlock(&ci->lock); } +/* + * Determine the locking method in use for this device. Return + * swap_cluster_info if SSD-style cluster-based locking is in place. + */ static inline struct swap_cluster_info *lock_cluster_or_swap_info( - struct swap_info_struct *si, - unsigned long offset) + struct swap_info_struct *si, unsigned long offset) { struct swap_cluster_info *ci; + /* Try to use fine-grained SSD-style locking if available: */ ci = lock_cluster(si, offset); + /* Otherwise, fall back to traditional, coarse locking: */ if (!ci) spin_lock(&si->lock); -- 2.16.4