From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f44.google.com (mail-wg0-f44.google.com [74.125.82.44]) by kanga.kvack.org (Postfix) with ESMTP id 0EBC86B006E for ; Fri, 15 May 2015 08:01:45 -0400 (EDT) Received: by wgin8 with SMTP id n8so110494655wgi.0 for ; Fri, 15 May 2015 05:01:44 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id pi9si2942924wic.96.2015.05.15.05.01.42 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 15 May 2015 05:01:43 -0700 (PDT) Message-ID: <5555E024.6060309@suse.cz> Date: Fri, 15 May 2015 14:01:40 +0200 From: Vlastimil Babka MIME-Version: 1.0 Subject: Re: [PATCHv5 05/28] mm: adjust FOLL_SPLIT for new refcounting References: <1429823043-157133-1-git-send-email-kirill.shutemov@linux.intel.com> <1429823043-157133-6-git-send-email-kirill.shutemov@linux.intel.com> <5555D2F7.5070301@suse.cz> <20150515113646.GE6250@node.dhcp.inet.fi> In-Reply-To: <20150515113646.GE6250@node.dhcp.inet.fi> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , Andrea Arcangeli , Hugh Dickins , Dave Hansen , Mel Gorman , Rik van Riel , 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 05/15/2015 01:36 PM, Kirill A. Shutemov wrote: > On Fri, May 15, 2015 at 01:05:27PM +0200, Vlastimil Babka wrote: >> On 04/23/2015 11:03 PM, Kirill A. Shutemov wrote: >>> We need to prepare kernel to allow transhuge pages to be mapped with >>> ptes too. We need to handle FOLL_SPLIT in follow_page_pte(). >>> >>> Also we use split_huge_page() directly instead of split_huge_page_pmd(). >>> split_huge_page_pmd() will gone. >> >> You still call split_huge_page_pmd() for the is_huge_zero_page(page) case. > > For huge zero page we split PMD into table of zero pages and don't touch > compound page under it. That's what split_huge_page_pmd() (renamed into > split_huge_pmd()) will do by the end of patchset. Ah, I see. >> Also, of the code around split_huge_page() you basically took from >> split_huge_page_pmd() and open-coded into follow_page_mask(), you didn't >> include the mmu notifier calls. Why are they needed in split_huge_page_pmd() >> but not here? > > We do need mmu notifier in split_huge_page_pmd() for huge zero page. When Oh, I guess that's obvious then... to someone, anyway. Thanks. In that case the patch seems fine. Acked-by: Vlastimil Babka > we need to split compound page we go into split_huge_page() which takes > care about mmut notifiers. > -- 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