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 94BDB6B025F for ; Tue, 29 Aug 2017 08:04:35 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id r133so5928798pgr.6 for ; Tue, 29 Aug 2017 05:04:35 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id g14si2180207pfd.491.2017.08.29.05.04.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 29 Aug 2017 05:04:34 -0700 (PDT) Date: Tue, 29 Aug 2017 14:04:26 +0200 From: Peter Zijlstra Subject: Re: [PATCH v2 14/20] mm: Provide speculative fault infrastructure Message-ID: <20170829120426.4ar56rbmiupbqmio@hirez.programming.kicks-ass.net> References: <1503007519-26777-1-git-send-email-ldufour@linux.vnet.ibm.com> <1503007519-26777-15-git-send-email-ldufour@linux.vnet.ibm.com> <20170827001823.n5wgkfq36z6snvf2@node.shutemov.name> <507e79d5-59df-c5b5-106d-970c9353d9bc@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <507e79d5-59df-c5b5-106d-970c9353d9bc@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour Cc: "Kirill A. Shutemov" , paulmck@linux.vnet.ibm.com, akpm@linux-foundation.org, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , 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 , linuxppc-dev@lists.ozlabs.org, x86@kernel.org On Tue, Aug 29, 2017 at 09:59:30AM +0200, Laurent Dufour wrote: > On 27/08/2017 02:18, Kirill A. Shutemov wrote: > >> + > >> + if (unlikely(!vma->anon_vma)) > >> + goto unlock; > > > > It deserves a comment. > > You're right I'll add it in the next version. > For the record, the root cause is that __anon_vma_prepare() requires the > mmap_sem to be held because vm_next and vm_prev must be safe. But should that test not be: if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) goto unlock; Because !anon vmas will never have ->anon_vma set and you don't want to exclude those. -- 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