From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id D7ED96B0044 for ; Wed, 28 Jan 2009 23:47:07 -0500 (EST) Date: Thu, 29 Jan 2009 05:42:27 +0100 From: Oleg Nesterov Subject: Re: [RFC v7] wait: prevent exclusive waiter starvation Message-ID: <20090129044227.GA5231@redhat.com> References: <20090121213813.GB23270@cmpxchg.org> <20090122202550.GA5726@redhat.com> <20090123095904.GA22890@cmpxchg.org> <20090123113541.GB12684@redhat.com> <20090123133050.GA19226@redhat.com> <20090126215957.GA3889@cmpxchg.org> <20090127032359.GA17359@redhat.com> <20090127193434.GA19673@cmpxchg.org> <20090127200544.GA28843@redhat.com> <20090128091453.GA22036@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090128091453.GA22036@cmpxchg.org> Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Chris Mason , Peter Zijlstra , Matthew Wilcox , Chuck Lever , Nick Piggin , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar List-ID: On 01/28, Johannes Weiner wrote: > > Add abort_exclusive_wait() which removes the process' wait descriptor > from the waitqueue, iff still queued, or wakes up the next waiter > otherwise. It does so under the waitqueue lock. Racing with a wake > up means the aborting process is either already woken (removed from > the queue) and will wake up the next waiter, or it will remove itself > from the queue and the concurrent wake up will apply to the next > waiter after it. > > Use abort_exclusive_wait() in __wait_event_interruptible_exclusive() > and __wait_on_bit_lock() when they were interrupted by other means > than a wake up through the queue. Imho, this all is right, and this patch should replace lock_page_killable-avoid-lost-wakeups.patch (except for stable tree). But I guess we need maintainer's opinion, we have them in cc ;) Oleg. -- 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