Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754599AbYJBQmk (ORCPT ); Thu, 2 Oct 2008 12:42:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753968AbYJBQmc (ORCPT ); Thu, 2 Oct 2008 12:42:32 -0400 Received: from pasmtpa.tele.dk ([80.160.77.114]:50172 "EHLO pasmtpA.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753933AbYJBQmc (ORCPT ); Thu, 2 Oct 2008 12:42:32 -0400 Date: Thu, 2 Oct 2008 18:42:11 +0200 From: Jens Axboe To: Arjan van de Ven Cc: Dave Chinner , Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org, Alan Cox Subject: Re: [PATCH] Give kjournald a IOPRIO_CLASS_RT io priority Message-ID: <20081002164211.GK19428@kernel.dk> References: <20081001215638.3a65134c.akpm@linux-foundation.org> <87fxnfpjqj.fsf@basil.nowhere.org> <20081002075511.GX19428@kernel.dk> <20081002093326.GF30001@disturbed> <20081002094537.GA19428@kernel.dk> <20081002061433.4e995075@infradead.org> <20081002132746.GG19428@kernel.dk> <20081002063606.512decb3@infradead.org> <20081002134736.GH19428@kernel.dk> <20081002072650.248373ea@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081002072650.248373ea@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1044 Lines: 29 On Thu, Oct 02 2008, Arjan van de Ven wrote: > On Thu, 2 Oct 2008 15:47:37 +0200 > Jens Axboe wrote: > > > Yes, it'll report '0' which means 'not set'. The kernel inteprets 'not > > set' as the default values, BE/4. There's a big diffence, since '0' > > means that we track CPU nice values where as if it returned be/4 then > > that is a strict/fixed setting. > > argh. "0" means both "not set" and "highest priority". Arjan, please read the interface, it does not... 0 means not set, period. What matters is the class setting, if that is non-zero then it is a valid setting. See #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data) So highest priority BE is IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0), which is of course valid. -- Jens Axboe -- 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/