Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753936AbZFHRuc (ORCPT ); Mon, 8 Jun 2009 13:50:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750727AbZFHRuX (ORCPT ); Mon, 8 Jun 2009 13:50:23 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:49850 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751190AbZFHRuW (ORCPT ); Mon, 8 Jun 2009 13:50:22 -0400 Date: Mon, 8 Jun 2009 18:50:18 +0100 From: Al Viro To: Miklos Szeredi Cc: 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, torvalds@linux-foundation.org, alan@lxorguk.ukuu.org.uk, gregkh@suse.de, npiggin@suse.de, akpm@linux-foundation.org, hch@infradead.org Subject: Re: [PATCH 0/23] File descriptor hot-unplug support v2 Message-ID: <20090608175018.GM8633@ZenIV.linux.org.uk> References: <20090606080334.GA15204@ZenIV.linux.org.uk> <20090608162913.GL8633@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1277 Lines: 31 On Mon, Jun 08, 2009 at 06:44:41PM +0200, Miklos Szeredi wrote: > I'm still not getting what the problem is. AFAICS file operations are > either > > a) non-interruptible but finish within a short time or > b) may block indefinitely but are interruptible (or at least killable). > > Anything else is already problematic, resulting in processes "stuck in > D state". 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 ... just for starters. If you sign up for auditing the tree to eliminate "something's stuck in D state", you are welcome to it. Mind you, you'll have to audit filesystems for "doesn't check if metadata IO has failed" first, but that _really_ needs to be done anyway. On the ongoing basis. Drivers, of course, are even more interesting - looking through foo_ioctl() instances is a wonderful way to lower pH in stomach, but that's on the "we want revoke()" side of 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/