Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422854AbWJPTcj (ORCPT ); Mon, 16 Oct 2006 15:32:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422855AbWJPTcj (ORCPT ); Mon, 16 Oct 2006 15:32:39 -0400 Received: from pne-smtpout2-sn1.fre.skanova.net ([81.228.11.159]:8356 "EHLO pne-smtpout2-sn1.fre.skanova.net") by vger.kernel.org with ESMTP id S1422854AbWJPTcj (ORCPT ); Mon, 16 Oct 2006 15:32:39 -0400 Date: Mon, 16 Oct 2006 21:32:37 +0200 (CEST) From: Peter Osterlund X-X-Sender: petero@p4.localdomain To: balagi@justmail.de cc: Jens Axboe , linux-kernel@vger.kernel.org Subject: Re: Re: [PATCH 2/2] 2.6.19-rc1-mm1 pktcdvd: bio write congestion In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 999 Lines: 22 On Mon, 16 Oct 2006, balagi@justmail.de wrote: > the congestion control will work with both code changes, but i am > not sure, if using clear_queue_congested() and blk_congestion_wait() > is the right thing to use here: it works on global level. Any other > thread/driver/etc. can do a clear_queue_congested() and wake > up anyone waiting on this global write or read wait queue, resulting to > unneeded task switches. > The driver local solution (own waitqueue) would prevent this..... But it would make the driver more complex. How many extra task switches can you get, and how much CPU time does that consume? If it is negligible I think it's better to keep the code simple. -- Peter Osterlund - petero2@telia.com http://web.telia.com/~u89404340 - 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/