Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755540AbXHPLxu (ORCPT ); Thu, 16 Aug 2007 07:53:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752257AbXHPLxk (ORCPT ); Thu, 16 Aug 2007 07:53:40 -0400 Received: from noname.neutralserver.com ([70.84.186.210]:51758 "EHLO noname.neutralserver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbXHPLxk (ORCPT ); Thu, 16 Aug 2007 07:53:40 -0400 Date: Thu, 16 Aug 2007 14:53:50 +0300 From: Dan Aloni To: Oleg Nesterov Cc: Andrew Morton , Alan Cox , "Eric W. Biederman" , Ingo Molnar , Jarek Poplawski , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] tty_io.c: don't use flush_scheduled_work() Message-ID: <20070816115349.GA26908@localdomain> References: <20070701153749.GA111@tv-sign.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070701153749.GA111@tv-sign.ru> User-Agent: Mutt/1.5.16 (2007-06-11) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - noname.neutralserver.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - monatomic.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1289 Lines: 28 On Sun, Jul 01, 2007 at 07:37:49PM +0400, Oleg Nesterov wrote: > I don't know how to test this patch, the ack/nack from maintainer is wanted. > > flush_scheduled_work() is evil and should be avoided. Change tty_set_ldisc() > and release_dev() to use cancel_delayed_work_sync/cancel_work_sync. > > I am not sure we really need to call do_tty_hangup() when cancel_work_sync() > returns true, but this matches the current behaviour. I also noticed this problem recently with 2.6.22, on a 2-CPU box where there was one SCHED_RR userspace process stuck in a busy loop. The box was completely responsive but had this annoyance where all tty closings were stuck in flush_scheduled_work(). It's especially noticable when you ssh to the machine and then try to log out. A temporary workaround was to give just the workqueue events/* threads a SCHED_FIFO static priority of 99, but I have kept that small patch to myself (figured it's just too nasty). -- Dan Aloni XIV LTD, http://www.xivstorage.com da-x (at) monatomic.org, dan (at) xiv.co.il - 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/