From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id EDCB66B0253 for ; Tue, 9 Aug 2016 13:25:36 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id 63so35175266pfx.0 for ; Tue, 09 Aug 2016 10:25:36 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id r5si43540930paa.190.2016.08.09.10.25.35 for ; Tue, 09 Aug 2016 10:25:35 -0700 (PDT) From: "Huang\, Ying" Subject: Re: [RFC 00/11] THP swap: Delay splitting THP during swapping out References: <1470760673-12420-1-git-send-email-ying.huang@intel.com> Date: Tue, 09 Aug 2016 10:25:34 -0700 In-Reply-To: <1470760673-12420-1-git-send-email-ying.huang@intel.com> (Ying Huang's message of "Tue, 9 Aug 2016 09:37:42 -0700") Message-ID: <87k2fp4zxt.fsf@yhuang-mobile.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , tim.c.chen@intel.com, dave.hansen@intel.com, andi.kleen@intel.com, aaron.lu@intel.com, "Kirill A . Shutemov" , Andrea Arcangeli Cc: "Huang, Ying" , linux-mm@kvack.org, linux-kernel@vger.kernel.org Hi, All, "Huang, Ying" writes: > From: Huang Ying > > This patchset is based on 8/4 head of mmotm/master. > > This is the first step for Transparent Huge Page (THP) swap support. > The plan is to delaying splitting THP step by step and avoid splitting > THP finally during THP swapping out and swapping in. > > The advantages of THP swap support are: > > - Batch swap operations for THP to reduce lock acquiring/releasing, > including allocating/freeing swap space, adding/deleting to/from swap > cache, and writing/reading swap space, etc. > > - THP swap space read/write will be 2M sequence IO. It is particularly > helpful for swap read, which usually are 4k random IO. > > - It will help memory fragmentation, especially when THP is heavily used > by the applications. 2M continuous pages will be free up after THP > swapping out. > > As the first step, in this patchset, the splitting huge page is > delayed from almost the first step of swapping out to after allocating > the swap space for THP and adding the THP into swap cache. This will > reduce lock acquiring/releasing for locks used for swap space and swap > cache management. For this patchset posting, In general, I want to check the basic design with memory management subsystem maintainers and developers. For [RFC 01/11] swap: Add swap_cluster_list, it is a cleanup patch. And I think it should be useful independently. I am not very confident about the memcg part, that is [RFC 03/11] mm, memcg: Add swap_cgroup_iter iterator [RFC 04/11] mm, memcg: Support to charge/uncharge multiple swap entries Please help me to check it. Best Regards, Huang, Ying -- 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