From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id 626436B00D4 for ; Sun, 12 Sep 2010 23:21:38 -0400 (EDT) Date: Mon, 13 Sep 2010 13:21:16 +1000 From: Neil Brown Subject: Re: [PATCH 05/17] writeback: quit throttling when signal pending Message-ID: <20100913132116.3917e5d5@notabene> In-Reply-To: <20100913015529.GB5312@localhost> References: <20100912154945.758129106@intel.com> <20100912155203.355459925@intel.com> <20100913064654.3cce885c@notabene> <20100913015529.GB5312@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: linux-mm , LKML , Andrew Morton , Theodore Ts'o , Dave Chinner , Jan Kara , Peter Zijlstra , Mel Gorman , Rik van Riel , KOSAKI Motohiro , Chris Mason , Christoph Hellwig , "Li, Shaohua" List-ID: On Mon, 13 Sep 2010 09:55:29 +0800 Wu Fengguang wrote: > On Mon, Sep 13, 2010 at 04:46:54AM +0800, Neil Brown wrote: > > On Sun, 12 Sep 2010 23:49:50 +0800 > > Wu Fengguang wrote: > > > > > This allows quick response to Ctrl-C etc. for impatient users. > > > > > > Signed-off-by: Wu Fengguang > > > --- > > > mm/page-writeback.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > --- linux-next.orig/mm/page-writeback.c 2010-09-09 16:01:14.000000000 +0800 > > > +++ linux-next/mm/page-writeback.c 2010-09-09 16:02:27.000000000 +0800 > > > @@ -553,6 +553,9 @@ static void balance_dirty_pages(struct a > > > __set_current_state(TASK_INTERRUPTIBLE); > > > io_schedule_timeout(pause); > > > > > > + if (signal_pending(current)) > > > + break; > > > + > > > > Given the patch description, I think you might want "fatal_signal_pending()" > > here ??? > > __fatal_signal_pending() tests SIGKILL only, while the one often used > and need more quick responding is SIGINT.. > I thought that at first too.... but I don't think that is the case. In kernel/signal.c, in complete_signal, we have if (sig_fatal() ...) .... sigaddset(&t->pending.signal, SIGKILL); where sig_fatal is #define sig_fatal(t, signr) \ (!siginmask(signr, SIG_KERNEL_IGNORE_MASK|SIG_KERNEL_STOP_MASK) && \ (t)->sighand->action[(signr)-1].sa.sa_handler == SIG_DFL) so (if I'm reading the code correctly), if a process receives a signal for which the handler is SIG_DFL, then SIGKILL is set in the pending mask, so __fatal_signal_pending will be true. So it fatal_signal_pending should catch any signal that will cause the process to exit. I assume that it what you want... NeilBrown -- 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