Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269370AbUINNSb (ORCPT ); Tue, 14 Sep 2004 09:18:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269371AbUINNSE (ORCPT ); Tue, 14 Sep 2004 09:18:04 -0400 Received: from clock-tower.bc.nu ([81.2.110.250]:24509 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id S269344AbUINNPJ (ORCPT ); Tue, 14 Sep 2004 09:15:09 -0400 Subject: Re: [patch] sched, tty: fix scheduling latencies in tty_io.c From: Alan Cox To: Ingo Molnar Cc: Andrew Morton , Linux Kernel Mailing List , Alexander Viro In-Reply-To: <20040914122748.GA6846@elte.hu> References: <20040914101904.GD24622@elte.hu> <20040914102517.GE24622@elte.hu> <20040914104449.GA30790@elte.hu> <20040914105048.GA31238@elte.hu> <20040914105904.GB31370@elte.hu> <20040914110237.GC31370@elte.hu> <20040914110611.GA32077@elte.hu> <1095159217.16572.29.camel@localhost.localdomain> <20040914120016.GA5422@elte.hu> <1095160687.16572.34.camel@localhost.localdomain> <20040914122748.GA6846@elte.hu> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1095163891.16520.54.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Tue, 14 Sep 2004 13:11:54 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1122 Lines: 24 On Maw, 2004-09-14 at 13:27, Ingo Molnar wrote: > would it be a sufficient fix to grab some sort of tty_sem mutex in the > places where the patch drops the BKL - or are there other entry paths to > this code? There are a whole load of entry points. I've been trying to document all the ldisc layer stuff as I fix the basic bugs in it. A semaphore isnt sufficient because some of the entry points have to be multi-entry so you'd need to go modify all the ldisc internals (I think that will have to happen eventually). It also relies on it for read v write locking still. So far all I've fixed is the vfs/ldisc locking to ensure that open/close and other events are properly sequenced. I've not yet finished tackling the ldisc/driver cases where driver->close() completes and the ldisc calls the driver still. At that point its at least then down to the drivers to get fixed. - 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/