From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936883AbdCXQuc (ORCPT ); Fri, 24 Mar 2017 12:50:32 -0400 Received: from mail-wr0-f175.google.com ([209.85.128.175]:34157 "EHLO mail-wr0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966732AbdCXQuS (ORCPT ); Fri, 24 Mar 2017 12:50:18 -0400 Date: Fri, 24 Mar 2017 19:50:14 +0300 From: "Kirill A. Shutemov" To: Zi Yan Cc: Zi Yan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kirill.shutemov@linux.intel.com, akpm@linux-foundation.org, minchan@kernel.org, vbabka@suse.cz, mgorman@techsingularity.net, mhocko@kernel.org, n-horiguchi@ah.jp.nec.com, khandual@linux.vnet.ibm.com, dnellans@nvidia.com Subject: Re: [PATCH v4 06/11] mm: thp: check pmd migration entry in common path Message-ID: <20170324165014.2ibdmurirjd4pa7r@node.shutemov.name> References: <20170313154507.3647-1-zi.yan@sent.com> <20170313154507.3647-7-zi.yan@sent.com> <20170324145042.bda52glerop5wydx@node.shutemov.name> <58D544B5.20102@cs.rutgers.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <58D544B5.20102@cs.rutgers.edu> User-Agent: NeoMutt/20170306 (1.8.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 24, 2017 at 11:09:25AM -0500, Zi Yan wrote: > Kirill A. Shutemov wrote: > > On Mon, Mar 13, 2017 at 11:45:02AM -0400, Zi Yan wrote: > > Again. That's doesn't look right.. > > It will be changed: > > ptl = pmd_lock(mm, pmd); > +retry_locked: > + if (unlikely(!pmd_present(*pmd))) { > + if (likely(!(flags & FOLL_MIGRATION))) { > + spin_unlock(ptl); > + return no_page_table(vma, flags); > + } > + pmd_migration_entry_wait(mm, pmd); > + goto retry_locked; Nope. pmd_migration_entry_wait() unlocks the ptl. -- Kirill A. Shutemov