From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id DD8C56B037C for ; Tue, 8 Aug 2017 05:46:54 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id 24so28116288pfk.5 for ; Tue, 08 Aug 2017 02:46:54 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id e7si655886plk.249.2017.08.08.02.46.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Aug 2017 02:46:53 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v789jR80143141 for ; Tue, 8 Aug 2017 05:46:52 -0400 Received: from e23smtp06.au.ibm.com (e23smtp06.au.ibm.com [202.81.31.148]) by mx0a-001b2d01.pphosted.com with ESMTP id 2c7ak3h6c7-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 08 Aug 2017 05:46:52 -0400 Received: from localhost by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Aug 2017 19:46:49 +1000 Received: from d23av05.au.ibm.com (d23av05.au.ibm.com [9.190.234.119]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v789kdea28639246 for ; Tue, 8 Aug 2017 19:46:47 +1000 Received: from d23av05.au.ibm.com (localhost [127.0.0.1]) by d23av05.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v789kEM9013565 for ; Tue, 8 Aug 2017 19:46:15 +1000 Subject: Re: [RFC v5 01/11] mm: Dont assume page-table invariance during faults References: <1497635555-25679-1-git-send-email-ldufour@linux.vnet.ibm.com> <1497635555-25679-2-git-send-email-ldufour@linux.vnet.ibm.com> From: Anshuman Khandual Date: Tue, 8 Aug 2017 15:15:50 +0530 MIME-Version: 1.0 In-Reply-To: <1497635555-25679-2-git-send-email-ldufour@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: <57cbb4ca-7f04-ac50-3321-2c34ac08307b@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour , paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, Tim Chen On 06/16/2017 11:22 PM, Laurent Dufour wrote: > From: Peter Zijlstra > > One of the side effects of speculating on faults (without holding > mmap_sem) is that we can race with free_pgtables() and therefore we > cannot assume the page-tables will stick around. > > Remove the relyance on the pte pointer. Looking into other parts of the series, it seemed like now we have sequence lock both at MM and VMA level but then after that we still need to take page table lock before handling page faults (in turn manipulating PTE which includes swap in paths as well). Is not that true ? -- 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