From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f180.google.com (mail-pd0-f180.google.com [209.85.192.180]) by kanga.kvack.org (Postfix) with ESMTP id 41EDF6B0035 for ; Fri, 25 Apr 2014 16:08:17 -0400 (EDT) Received: by mail-pd0-f180.google.com with SMTP id x10so86279pdj.39 for ; Fri, 25 Apr 2014 13:08:16 -0700 (PDT) Received: from mail-pb0-x234.google.com (mail-pb0-x234.google.com [2607:f8b0:400e:c01::234]) by mx.google.com with ESMTPS id oz6si5492127pac.420.2014.04.25.13.08.16 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 25 Apr 2014 13:08:16 -0700 (PDT) Received: by mail-pb0-f52.google.com with SMTP id rq2so3562161pbb.25 for ; Fri, 25 Apr 2014 13:08:15 -0700 (PDT) Date: Fri, 25 Apr 2014 13:07:01 -0700 (PDT) From: Hugh Dickins Subject: Re: [PATCH] mm: get_user_pages(write,force) refuse to COW in shared areas In-Reply-To: <20140425190931.GA11323@redhat.com> Message-ID: References: <20140424133055.GA13269@redhat.com> <20140425190931.GA11323@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov Cc: Linus Torvalds , Andrew Morton , Jan Kara , Roland Dreier , Konstantin Khlebnikov , "Kirill A. Shutemov" , Mauro Carvalho Chehab , Omar Ramirez Luna , Inki Dae , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org On Fri, 25 Apr 2014, Oleg Nesterov wrote: > > And I forgot to mention, there is another reason why I would like to > change uprobes to follow the same convention. I still think it would > be better to kill __replace_page() and use gup(FOLL_WRITE | FORCE) > in uprobe_write_opcode(). Oh, please please do! I assumed there was a good atomicity reason for doing it that way, but if you can do it with gup() please do so. I went off into a little rant about __replace_page() in my reply to you; but then felt that you had approached with an honest enquiry, and didn't deserve a rant in response, so I deleted it. And, of course, I'm conscious that I have from start to finish withheld my involvement from uprobes, and refused to review that __replace_page() (beyond insisting that it not be put in a common place for sharing with KSM, because I just couldn't guarantee it for uprobes). I'm afraid that it's much like HWPoison to me, a complexity (nastiness?) way beyond what I have time to support myself. Hugh -- 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