From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id C5F2C6B004D for ; Mon, 8 Jun 2009 14:48:23 -0400 (EDT) Date: Mon, 8 Jun 2009 19:50:41 +0100 From: Al Viro Subject: Re: [PATCH 0/23] File descriptor hot-unplug support v2 Message-ID: <20090608185041.GN8633@ZenIV.linux.org.uk> References: <20090606080334.GA15204@ZenIV.linux.org.uk> <20090608162913.GL8633@ZenIV.linux.org.uk> <20090608175018.GM8633@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Linus Torvalds Cc: Miklos Szeredi , ebiederm@xmission.com, 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, npiggin@suse.de, akpm@linux-foundation.org, hch@infradead.org List-ID: On Mon, Jun 08, 2009 at 11:01:51AM -0700, Linus Torvalds wrote: > > > On Mon, 8 Jun 2009, Al Viro wrote: > > > > Welcome to reality... > > > > * bread() is non-interruptible > > * so's copy_from_user()/copy_to_user() > > * IO we are stuck upon _might_ be interruptible, but by sending a signal > > to some other process > > We can probably improve on these, though. > > Like the copy_to/from_user thing. We might well be able to do that whole > "if it's a fatal signal, return early" thing. > > So in the _general_ case - no, we probably can't fix things. But we could > likely at least improve in some common cases if we cared. 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. -- 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