Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753673AbbGOLbZ (ORCPT ); Wed, 15 Jul 2015 07:31:25 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:42433 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751828AbbGOLbX (ORCPT ); Wed, 15 Jul 2015 07:31:23 -0400 X-Helo: d28dlp02.in.ibm.com X-MailFrom: aneesh.kumar@linux.vnet.ibm.com X-RcptTo: linux-kernel@vger.kernel.org From: "Aneesh Kumar K.V" To: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Hugh Dickins Cc: Dave Hansen , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" Subject: Re: [PATCH 00/36] THP refcounting redesign In-Reply-To: <1436550130-112636-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1436550130-112636-1-git-send-email-kirill.shutemov@linux.intel.com> User-Agent: Notmuch/0.19+103~g294bb6d (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Wed, 15 Jul 2015 17:00:47 +0530 Message-ID: <87twt51wuw.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15071511-0017-0000-0000-0000062BF737 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1419 Lines: 36 "Kirill A. Shutemov" writes: > Hello everybody, > > The THP refcounting has been rebased onto current since-4.1 as requested. > > 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. > > 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 people look on this code before-and-after to > justify time budget on reviewing this patchset. > Tested this series of ppc64. Please feel free to add to the series Tested-by: Aneesh Kumar K.V -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/