From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: poll: allow f_op->poll to sleep, take #3 Date: Sun, 23 Nov 2008 09:59:02 +0100 Message-ID: <20081123085902.GI30453@elte.hu> References: <20081122123942.GF5707@parisc-linux.org> <4927FE87.6050005@gmail.com> <20081122105356.87856d04.akpm@linux-foundation.org> <4928B162.9030404@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Tejun Heo , Andrew Morton , Matthew Wilcox , Miklos Szeredi , arjan@linux.intel.com, Linus Torvalds , hch@infradead.org, rminnich@sandia.gov, ericvh@gmail.com, Linux Kernel Mailing List , linux-fsdevel@vger.kernel.org To: Davide Libenzi Return-path: Received: from mx3.mail.elte.hu ([157.181.1.138]:40373 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752383AbYKWI71 (ORCPT ); Sun, 23 Nov 2008 03:59:27 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: * Davide Libenzi wrote: > On Sun, 23 Nov 2008, Tejun Heo wrote: > > > +static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) > > +{ > > + struct poll_wqueues *pwq = wait->private; > > + DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task); > > + > > + set_mb(pwq->triggered, 1); > > + > > + /* perform the default wake up operation */ > > + return default_wake_function(&dummy_wait, mode, sync, key); > > +} > > Wouldn't it be nicer to un-static try_to_wake_up() (or a wrapper) > instead of setting up a fake wait queue just to use > default_wake_function(), just to wake up a task? the already existing single-task-wakeup shortcut method made available by the scheduler is wake_up_process(). A number of primitives where waitqueue overhead is of concern already make use of it. (mutexes/rtmutexes and more) if you need a different mode flag, then please extend the wake_up_process() family of APIs. Ingo