From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 399766B02F4 for ; Tue, 8 Aug 2017 08:11:56 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id g32so4370105wrd.8 for ; Tue, 08 Aug 2017 05:11:56 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id k1si1111422wrf.34.2017.08.08.05.11.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Aug 2017 05:11:54 -0700 (PDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v78C4s9u144731 for ; Tue, 8 Aug 2017 08:11:53 -0400 Received: from e06smtp12.uk.ibm.com (e06smtp12.uk.ibm.com [195.75.94.108]) by mx0b-001b2d01.pphosted.com with ESMTP id 2c7c2s4983-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 08 Aug 2017 08:11:53 -0400 Received: from localhost by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Aug 2017 13:11:50 +0100 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> <57cbb4ca-7f04-ac50-3321-2c34ac08307b@linux.vnet.ibm.com> From: Laurent Dufour Date: Tue, 8 Aug 2017 14:11:44 +0200 MIME-Version: 1.0 In-Reply-To: <57cbb4ca-7f04-ac50-3321-2c34ac08307b@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: Sender: owner-linux-mm@kvack.org List-ID: To: Anshuman Khandual , 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, npiggin@gmail.com, bsingharora@gmail.com, Tim Chen On 08/08/2017 11:45, Anshuman Khandual wrote: > 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 ? Page table locking is still required as several VMAs can reference the same page table. -- 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