From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f172.google.com (mail-wi0-f172.google.com [209.85.212.172]) by kanga.kvack.org (Postfix) with ESMTP id 86E4A6B0070 for ; Fri, 15 May 2015 07:36:59 -0400 (EDT) Received: by wicmx19 with SMTP id mx19so58447911wic.0 for ; Fri, 15 May 2015 04:36:59 -0700 (PDT) Received: from kirsi1.inet.fi (mta-out1.inet.fi. [62.71.2.227]) by mx.google.com with ESMTP id fa5si146423wjc.199.2015.05.15.04.36.57 for ; Fri, 15 May 2015 04:36:58 -0700 (PDT) Date: Fri, 15 May 2015 14:36:46 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCHv5 05/28] mm: adjust FOLL_SPLIT for new refcounting Message-ID: <20150515113646.GE6250@node.dhcp.inet.fi> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5555D2F7.5070301@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka 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 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. > 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 we need to split compound page we go into split_huge_page() which takes care about mmut notifiers. -- Kirill A. Shutemov -- 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