From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965346AbbD0XDw (ORCPT ); Mon, 27 Apr 2015 19:03:52 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:40276 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752668AbbD0XDu (ORCPT ); Mon, 27 Apr 2015 19:03:50 -0400 Date: Mon, 27 Apr 2015 16:03:48 -0700 From: Andrew Morton To: "Kirill A. Shutemov" Cc: Andrea Arcangeli , Hugh Dickins , Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv5 00/28] THP refcounting redesign Message-Id: <20150427160348.fa3aefc5fc557e429d6b0295@linux-foundation.org> In-Reply-To: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 24 Apr 2015 00:03:35 +0300 "Kirill A. Shutemov" wrote: > Hello everybody, > > Here's reworked version of my patchset. All known issues were addressed. > > The goal of patchset is to make refcounting on THP pages cheaper with > simpler semantics and allow the same THP compound page to be mapped with > PMD and PTEs. This is required to get reasonable THP-pagecache > implementation. Are there any measurable performance improvements? > With the new refcounting design it's much easier to protect against > split_huge_page(): simple reference on a page will make you the deal. > It makes gup_fast() implementation simpler and doesn't require > special-case in futex code to handle tail THP pages. > > It should improve THP utilization over the system since splitting THP in > one process doesn't necessary lead to splitting the page in all other > processes have the page mapped. > > The patchset drastically lower complexity of get_page()/put_page() > codepaths. I encourage reviewers look on this code before-and-after to > justify time budget on reviewing this patchset. > > ... > > 59 files changed, 1144 insertions(+), 1509 deletions(-) It's huge. I'm going to need help reviewing this. Have earlier versions been reviewed much? Who do you believe are suitable reviewers? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 2ABF86B006C for ; Mon, 27 Apr 2015 19:03:51 -0400 (EDT) Received: by pacwv17 with SMTP id wv17so122401060pac.0 for ; Mon, 27 Apr 2015 16:03:50 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id g2si31812490pdp.243.2015.04.27.16.03.50 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Apr 2015 16:03:50 -0700 (PDT) Date: Mon, 27 Apr 2015 16:03:48 -0700 From: Andrew Morton Subject: Re: [PATCHv5 00/28] THP refcounting redesign Message-Id: <20150427160348.fa3aefc5fc557e429d6b0295@linux-foundation.org> In-Reply-To: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.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: "Kirill A. Shutemov" Cc: Andrea Arcangeli , Hugh Dickins , Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Fri, 24 Apr 2015 00:03:35 +0300 "Kirill A. Shutemov" wrote: > Hello everybody, > > Here's reworked version of my patchset. All known issues were addressed. > > The goal of patchset is to make refcounting on THP pages cheaper with > simpler semantics and allow the same THP compound page to be mapped with > PMD and PTEs. This is required to get reasonable THP-pagecache > implementation. Are there any measurable performance improvements? > With the new refcounting design it's much easier to protect against > split_huge_page(): simple reference on a page will make you the deal. > It makes gup_fast() implementation simpler and doesn't require > special-case in futex code to handle tail THP pages. > > It should improve THP utilization over the system since splitting THP in > one process doesn't necessary lead to splitting the page in all other > processes have the page mapped. > > The patchset drastically lower complexity of get_page()/put_page() > codepaths. I encourage reviewers look on this code before-and-after to > justify time budget on reviewing this patchset. > > ... > > 59 files changed, 1144 insertions(+), 1509 deletions(-) It's huge. I'm going to need help reviewing this. Have earlier versions been reviewed much? Who do you believe are suitable reviewers? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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