From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f49.google.com (mail-ee0-f49.google.com [74.125.83.49]) by kanga.kvack.org (Postfix) with ESMTP id 635E06B0035 for ; Tue, 6 May 2014 19:06:06 -0400 (EDT) Received: by mail-ee0-f49.google.com with SMTP id e53so176455eek.8 for ; Tue, 06 May 2014 16:06:05 -0700 (PDT) Received: from jenni2.inet.fi (mta-out1.inet.fi. [62.71.2.199]) by mx.google.com with ESMTP id 45si14562601eeh.243.2014.05.06.16.06.04 for ; Tue, 06 May 2014 16:06:04 -0700 (PDT) Date: Wed, 7 May 2014 02:03:23 +0300 From: "Kirill A. Shutemov" Subject: Re: [RFC, PATCH 0/8] remap_file_pages() decommission Message-ID: <20140506230323.GA14821@node.dhcp.inet.fi> References: <1399387052-31660-1-git-send-email-kirill.shutemov@linux.intel.com> <20140506143542.1d4e5f41be58b3ad3543ffe3@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Andrew Morton , "Kirill A. Shutemov" , linux-mm , Peter Zijlstra , Ingo Molnar On Tue, May 06, 2014 at 02:51:24PM -0700, Linus Torvalds wrote: > On Tue, May 6, 2014 at 2:35 PM, Andrew Morton wrote: > > On Tue, 6 May 2014 17:37:24 +0300 "Kirill A. Shutemov" wrote: > > > >> This patchset replaces the syscall with emulation which creates new VMA on > >> each remap and remove code to support non-linear mappings. > >> > >> Nonlinear mappings are pain to support and it seems there's no legitimate > >> use-cases nowadays since 64-bit systems are widely available. > >> > >> It's not yet ready to apply. Just to give rough idea of what can we get if > >> we'll deprecated remap_file_pages(). > >> > >> I need to split patches properly and write correct commit messages. And there's > >> still code to remove. > > > > hah. That's bold. It would be great if we can get away with this. > > > > Do we have any feeling for who will be impacted by this and how badly? > > I *would* love to get rid of the nonlinear mappings, but I really have > zero visibility into who ended up using it. I assume it's a "Oracle on > 32-bit x86" kind of thing. There're funny PyPy people who wants to use remap_file_pages() in new code to build software transaction memory[1]. It sounds just crazy to me. [1] https://lwn.net/Articles/587923/ > I think this is more of a distro question. Plus perhaps an early patch > to just add a warning first so that we can see who it triggers for? Something like this?