From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id BA7206B0260 for ; Wed, 16 Nov 2016 06:13:04 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id m203so21945237wma.2 for ; Wed, 16 Nov 2016 03:13:04 -0800 (PST) Received: from mail-wm0-x243.google.com (mail-wm0-x243.google.com. [2a00:1450:400c:c09::243]) by mx.google.com with ESMTPS id y130si6825535wmc.29.2016.11.16.03.13.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Nov 2016 03:13:03 -0800 (PST) Received: by mail-wm0-x243.google.com with SMTP id a20so9966332wme.2 for ; Wed, 16 Nov 2016 03:13:03 -0800 (PST) Date: Wed, 16 Nov 2016 14:13:01 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH 01/21] mm: Join struct fault_env and vm_fault Message-ID: <20161116111301.GA27027@node.shutemov.name> References: <1478233517-3571-1-git-send-email-jack@suse.cz> <1478233517-3571-2-git-send-email-jack@suse.cz> <20161115215021.GA23021@node> <20161116105132.GR3142@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161116105132.GR3142@twins.programming.kicks-ass.net> Sender: owner-linux-mm@kvack.org List-ID: To: Peter Zijlstra Cc: Jan Kara , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-nvdimm@ml01.01.org, Andrew Morton , Ross Zwisler , "Kirill A. Shutemov" On Wed, Nov 16, 2016 at 11:51:32AM +0100, Peter Zijlstra wrote: > On Wed, Nov 16, 2016 at 12:50:21AM +0300, Kirill A. Shutemov wrote: > > On Fri, Nov 04, 2016 at 05:24:57AM +0100, Jan Kara wrote: > > > Currently we have two different structures for passing fault information > > > around - struct vm_fault and struct fault_env. DAX will need more > > > information in struct vm_fault to handle its faults so the content of > > > that structure would become event closer to fault_env. Furthermore it > > > would need to generate struct fault_env to be able to call some of the > > > generic functions. So at this point I don't think there's much use in > > > keeping these two structures separate. Just embed into struct vm_fault > > > all that is needed to use it for both purposes. > > > > > > Signed-off-by: Jan Kara > > > > I'm not necessary dislike this, but I remember Peter had objections before > > when I proposed something similar. > > > > Peter? > > My objection was that it would be a layering violation. The 'filesystem' > shouldn't know about page-tables, all it should do is return a page > matching a specific offset. Well, this layering violation is already there (blame me): see vm_ops->map_pages(). :P > So fault_env manages the core vm parts and has the page-table bits in, > vm_fault manages the filesystem interface and gets us a page given an > offset. > > Now, I'm entirely out of touch wrt DAX, so I've not idea what that > needs/wants. I think we are better off with one structure. It streamlines code in quite a few places. -- Kirill A. Shutemov -- 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