From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 61B0B6B004F for ; Tue, 23 Jun 2009 23:18:14 -0400 (EDT) Received: by wa-out-1112.google.com with SMTP id m34so78699wag.22 for ; Tue, 23 Jun 2009 20:18:46 -0700 (PDT) Message-ID: <4A419A7F.8050604@gmail.com> Date: Wed, 24 Jun 2009 11:16:15 +0800 From: Huang Shijie MIME-Version: 1.0 Subject: Re: [PATCH] remove unused line for mmap_region() References: <1245595421-3441-1-git-send-email-shijie8@gmail.com> <4A3EFF93.4000100@gmail.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Hugh Dickins Cc: akpm@linux-foundation.org, linux-mm@kvack.org List-ID: > I can't name a list of drivers offhand, no (but note VM_PFNMAP areas > have a particular use for vm_pgoff, so all those drivers are likely > to be on the list). May I please leave that investigation to you? > > ok. > What I expect you to find in the end is that every driver which does > meddle with pgoff in its ->mmap, also has some other characteristic > (e.g. sets VM_IO or VM_DONTEXPAND or VM_RESERVED or VM_PFNMAP, or > even some other flag which the new vm_flags wouldn't have set), > which will prevent its vmas being merged anyway. > > Unfortunately,the driver's -->mmap is called below the vma_merge(), so even if the driver sets the VM_SPECIAL flag, it does not prevent the vmas being merged actually. -- 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