From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f52.google.com (mail-pa0-f52.google.com [209.85.220.52]) by kanga.kvack.org (Postfix) with ESMTP id 2B43A6B0038 for ; Tue, 17 Mar 2015 05:43:19 -0400 (EDT) Received: by pagr17 with SMTP id r17so5080372pag.0 for ; Tue, 17 Mar 2015 02:43:18 -0700 (PDT) Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com. [202.81.31.141]) by mx.google.com with ESMTPS id bx6si28243869pdb.26.2015.03.17.02.43.16 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 17 Mar 2015 02:43:18 -0700 (PDT) Received: from /spool/local by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 17 Mar 2015 19:43:12 +1000 Received: from d23relay10.au.ibm.com (d23relay10.au.ibm.com [9.190.26.77]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id E8B1B357804F for ; Tue, 17 Mar 2015 20:43:09 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2H9gxmu40370238 for ; Tue, 17 Mar 2015 20:43:09 +1100 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2H9gY8A000813 for ; Tue, 17 Mar 2015 20:42:34 +1100 From: "Aneesh Kumar K.V" Subject: Re: [PATCHv4 00/24] THP refcounting redesign In-Reply-To: <1425486792-93161-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1425486792-93161-1-git-send-email-kirill.shutemov@linux.intel.com> Date: Tue, 17 Mar 2015 15:12:05 +0530 Message-ID: <8761a0arki.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli Cc: Dave Hansen , Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , Johannes Weiner , Michal Hocko , Jerome Marchand , linux-kernel@vger.kernel.org, linux-mm@kvack.org "Kirill A. Shutemov" writes: > Hello everybody, > > It's bug-fix update of my thp refcounting work. > > 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. I tested this patch on ppc64 and verified thp allocation and split. I also checked the subpage_prot and it worked as expected. I will run more tests with this series and update if I find any issues. -aneesh -- 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