From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932784AbcHIQlx (ORCPT ); Tue, 9 Aug 2016 12:41:53 -0400 Received: from mga09.intel.com ([134.134.136.24]:51242 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247AbcHIQiN (ORCPT ); Tue, 9 Aug 2016 12:38:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,495,1464678000"; d="scan'208";a="1032535845" From: "Huang, Ying" To: Andrew Morton Cc: tim.c.chen@intel.com, dave.hansen@intel.com, andi.kleen@intel.com, aaron.lu@intel.com, "Kirill A . Shutemov" , Andrea Arcangeli , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel Subject: [RFC 02/11] swap: Change SWAPFILE_CLUSTER to 512 Date: Tue, 9 Aug 2016 09:37:44 -0700 Message-Id: <1470760673-12420-3-git-send-email-ying.huang@intel.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1470760673-12420-1-git-send-email-ying.huang@intel.com> References: <1470760673-12420-1-git-send-email-ying.huang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Huang Ying In this patch, the size of swap cluster is changed to that of THP on x86_64 (512). This is for THP (Transparent Huge Page) swap support on x86_64. Where one swap cluster will be used to hold the contents of each THP swapped out. And some information of the swapped out THP (such as compound map count) will be recorded in the swap_cluster_info data structure. In effect, this will enlarge swap cluster size by 2 times. Which may make it harder to find a free cluster when swap space becomes fragmented. So that, this may reduce the continuous swap space allocation and sequence write if that happens in theory. The performance test in 0day show no regressions caused by this. Cc: Hugh Dickins Cc: Shaohua Li Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: "Huang, Ying" --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 09e3877..18f9292 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -196,7 +196,7 @@ static void discard_swap_cluster(struct swap_info_struct *si, } } -#define SWAPFILE_CLUSTER 256 +#define SWAPFILE_CLUSTER 512 #define LATENCY_LIMIT 256 static inline void cluster_set_flag(struct swap_cluster_info *info, -- 2.8.1