From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964912AbdCXKwN (ORCPT ); Fri, 24 Mar 2017 06:52:13 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:39778 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754657AbdCXKwE (ORCPT ); Fri, 24 Mar 2017 06:52:04 -0400 Date: Fri, 24 Mar 2017 11:51:53 +0100 From: Peter Zijlstra To: "Kirill A. Shutemov" Cc: Ingo Molnar , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Fengguang Wu , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, LKP , Linus Torvalds , "Aneesh Kumar K.V" Subject: Re: [x86/mm/gup] 2947ba054a [ 71.329069] kernel BUG at include/linux/pagemap.h:151! Message-ID: <20170324105153.xvy5rcuawicqoanl@hirez.programming.kicks-ass.net> References: <20170319225124.xodpqjldom6ceazz@wfg-t540p.sh.intel.com> <20170324102436.xltop6udkx5pg4oq@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170324102436.xltop6udkx5pg4oq@node.shutemov.name> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 24, 2017 at 01:24:36PM +0300, Kirill A. Shutemov wrote: > I'm not sure what is the best way to fix this. > Few options: > - Drop the VM_BUG(); > - Bump preempt count during __get_user_pages_fast(); > - Use get_page() instead of page_cache_get_speculative() on x86. > > Any opinions? I think I'm in favour of the first; either remove or amend to include irqs_disabled() or so. This in favour of keeping the variants of GUP down. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id D497B6B0333 for ; Fri, 24 Mar 2017 06:52:01 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id q126so21995715pga.0 for ; Fri, 24 Mar 2017 03:52:01 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id w67si1661468pfd.29.2017.03.24.03.52.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 24 Mar 2017 03:52:00 -0700 (PDT) Date: Fri, 24 Mar 2017 11:51:53 +0100 From: Peter Zijlstra Subject: Re: [x86/mm/gup] 2947ba054a [ 71.329069] kernel BUG at include/linux/pagemap.h:151! Message-ID: <20170324105153.xvy5rcuawicqoanl@hirez.programming.kicks-ass.net> References: <20170319225124.xodpqjldom6ceazz@wfg-t540p.sh.intel.com> <20170324102436.xltop6udkx5pg4oq@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170324102436.xltop6udkx5pg4oq@node.shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Ingo Molnar , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Fengguang Wu , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, LKP , Linus Torvalds , "Aneesh Kumar K.V" On Fri, Mar 24, 2017 at 01:24:36PM +0300, Kirill A. Shutemov wrote: > I'm not sure what is the best way to fix this. > Few options: > - Drop the VM_BUG(); > - Bump preempt count during __get_user_pages_fast(); > - Use get_page() instead of page_cache_get_speculative() on x86. > > Any opinions? I think I'm in favour of the first; either remove or amend to include irqs_disabled() or so. This in favour of keeping the variants of GUP down. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0447952032733194728==" MIME-Version: 1.0 From: Peter Zijlstra To: lkp@lists.01.org Subject: Re: [x86/mm/gup] 2947ba054a [ 71.329069] kernel BUG at include/linux/pagemap.h:151! Date: Fri, 24 Mar 2017 11:51:53 +0100 Message-ID: <20170324105153.xvy5rcuawicqoanl@hirez.programming.kicks-ass.net> In-Reply-To: <20170324102436.xltop6udkx5pg4oq@node.shutemov.name> List-Id: --===============0447952032733194728== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Fri, Mar 24, 2017 at 01:24:36PM +0300, Kirill A. Shutemov wrote: > I'm not sure what is the best way to fix this. > Few options: > - Drop the VM_BUG(); > - Bump preempt count during __get_user_pages_fast(); > - Use get_page() instead of page_cache_get_speculative() on x86. > = > Any opinions? I think I'm in favour of the first; either remove or amend to include irqs_disabled() or so. This in favour of keeping the variants of GUP down. --===============0447952032733194728==--