Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759867AbZFIKxE (ORCPT ); Tue, 9 Jun 2009 06:53:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754996AbZFIKww (ORCPT ); Tue, 9 Jun 2009 06:52:52 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36666 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755123AbZFIKwv (ORCPT ); Tue, 9 Jun 2009 06:52:51 -0400 Date: Tue, 9 Jun 2009 12:52:51 +0200 From: Nick Piggin To: "Eric W. Biederman" Cc: Linus Torvalds , Al Viro , Miklos Szeredi , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hugh@veritas.com, tj@kernel.org, adobriyan@gmail.com, alan@lxorguk.ukuu.org.uk, gregkh@suse.de, akpm@linux-foundation.org, hch@infradead.org Subject: Re: [PATCH 0/23] File descriptor hot-unplug support v2 Message-ID: <20090609105251.GK14820@wotan.suse.de> References: <20090606080334.GA15204@ZenIV.linux.org.uk> <20090608162913.GL8633@ZenIV.linux.org.uk> <20090608175018.GM8633@ZenIV.linux.org.uk> <20090608185041.GN8633@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1498 Lines: 34 On Mon, Jun 08, 2009 at 11:42:53PM -0700, Eric W. Biederman wrote: > Linus Torvalds writes: > > > On Mon, 8 Jun 2009, Al Viro wrote: > >> > >> Sure, even though I'm not at all certain that copy_from_user() is that easy. > >> We can make locking current->mm in there interruptible, all right, but that's > >> only a part of the answer - even aside of the allocations, we'd need vma > >> ->fault() interruptible as well, which leads to interruptible instances of > >> ->readpage(), with all the fun _that_ would be. > > > > We already have all that - the NFS people wanted it. > > > > More importantly, you don't actually need to interrupt readpage itself - > > you just need to stop _waiting_ on it. So in your fault handler, just stop > > waiting, and instead just return FAULT_RETRY or whatever. > > That sounds doable. Has that code been merged yet? > > I took a quick look and it didn't see anyone breaking out of page fault with a > signal or code to really handle that. The problem is get_user_pages I think. Now that we have a good number of fault flags, we can pass down whether the caller is able to be interrupted or not. Ben H had some interest in doing this, but I don't know how far he got with it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/