From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 758B06B0038 for ; Thu, 1 Sep 2016 17:22:49 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id m89so34593056pfj.1 for ; Thu, 01 Sep 2016 14:22:49 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id zd5si7369676pac.155.2016.09.01.14.22.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 01 Sep 2016 14:22:48 -0700 (PDT) Date: Thu, 1 Sep 2016 14:22:46 -0700 From: Andrew Morton Subject: Re: [PATCH -v2 01/10] swap: Change SWAPFILE_CLUSTER to 512 Message-Id: <20160901142246.631fe47a558bb7522f73c034@linux-foundation.org> In-Reply-To: <1472743023-4116-2-git-send-email-ying.huang@intel.com> References: <1472743023-4116-1-git-send-email-ying.huang@intel.com> <1472743023-4116-2-git-send-email-ying.huang@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Huang, Ying" Cc: tim.c.chen@intel.com, dave.hansen@intel.com, andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel On Thu, 1 Sep 2016 08:16:54 -0700 "Huang, Ying" wrote: > From: Huang Ying > > In this patch, the size of the swap cluster is changed to that of the > THP (Transparent Huge Page) on x86_64 architecture (512). This is for > the THP 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 the swap space becomes > fragmented. So that, this may reduce the continuous swap space > allocation and sequential write in theory. The performance test in 0day > show no regressions caused by this. > > --- 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 > What happens to architectures which have different HPAGE_SIZE and/or PAGE_SIZE? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org