From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id A9B476B0047 for ; Wed, 11 Mar 2009 18:10:41 -0400 (EDT) Date: Wed, 11 Mar 2009 15:07:48 -0700 (PDT) From: Linus Torvalds Subject: Re: [aarcange@redhat.com: [PATCH] fork vs gup(-fast) fix] In-Reply-To: Message-ID: References: <20090311174103.GA11979@elte.hu> <20090311183748.GK27823@random.random> <20090311195935.GO27823@random.random> <20090311205529.GR27823@random.random> <20090311215721.GS27823@random.random> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Andrea Arcangeli Cc: Ingo Molnar , Nick Piggin , Hugh Dickins , KOSAKI Motohiro , KAMEZAWA Hiroyuki , linux-mm@kvack.org List-ID: On Wed, 11 Mar 2009, Linus Torvalds wrote: > > An we could add a warning for it. Something like "if this is a threaded > program, and it has ever used get_user_pages(), and it does a fork(), warn > about it once". Maybe people would realize what a stupid thing they are > doing, and that there is a simple fix (vfork). Ehh. vfork is only simple if you literally are going to execve. If you are using a fork as some kind of odd way to snapshot, I don't know what you should do. You can't sanely snapshot a threaded app with fork, but I bet some people try. Linus -- 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