Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932165AbVLALgO (ORCPT ); Thu, 1 Dec 2005 06:36:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932167AbVLALgO (ORCPT ); Thu, 1 Dec 2005 06:36:14 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:18607 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932165AbVLALgN (ORCPT ); Thu, 1 Dec 2005 06:36:13 -0500 Date: Thu, 1 Dec 2005 11:36:10 +0000 From: Christoph Hellwig To: Dan Aloni Cc: Luke-Jr , Linux Kernel Mailing List Subject: Re: [PATCH 2.4.x] prevent emulated SCSI hosts from wasting DMA memory Message-ID: <20051201113610.GG3958@infradead.org> Mail-Followup-To: Christoph Hellwig , Dan Aloni , Luke-Jr , Linux Kernel Mailing List References: <20051130171520.GB15505@localdomain> <200511301933.48668.luke-jr@utopios.org> <20051130210222.GA32431@localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051130210222.GA32431@localdomain> User-Agent: Mutt/1.4.2.1i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1193 Lines: 23 On Wed, Nov 30, 2005 at 11:02:23PM +0200, Dan Aloni wrote: > On Wed, Nov 30, 2005 at 07:33:47PM +0000, Luke-Jr wrote: > > On Wednesday 30 November 2005 17:15, Dan Aloni wrote: > > > Emulated scsi hosts don't do DMA, so don't unnecessarily increase > > > the SCSI DMA pool. > > > > They don't? Recently I learned(?) that apparently using hdparm -d on the > > old /dev/hdX device still worked/applied when using ide-scsi... or do > > "emulated scsi hosts" refer to something else? > > Actually by 'do DMA' I meant use the scsi_malloc() interface - which > is mostly used by low level drivers. The IDE drivers allocate their > DMA memory outside the SCSI layer. iSCSI hosts for instance, don't > need to cause unnecessary DMA allocations. (1) there's no guranteee a driver setting ->emulated can't use scsi_malloc (2) 2.4.x is very late in the cycle so there's just no point in putting this in (and in 2.6.x scsi_malloc is gone fortunately) - 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/