Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755767Ab1BKJw5 (ORCPT ); Fri, 11 Feb 2011 04:52:57 -0500 Received: from mail-qy0-f174.google.com ([209.85.216.174]:52600 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755335Ab1BKJwz convert rfc822-to-8bit (ORCPT ); Fri, 11 Feb 2011 04:52:55 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=l3hB0R405NiK4g2jc2hcGheNIGXT5RfjtJ9Hs3h4pEinhOgBFdr+7lCdU1qlx5kzpJ 59GXqTVXB+A+8Wu9bw+Km3aGfC81C0G8lXIGG9ZBw9N/y5WmPbCVKQibENDfvX0AXbFS c/1C54etcwT7XJPOxgtXN0odRnc+1nej1Iako= MIME-Version: 1.0 In-Reply-To: <1297350456.4933.25.camel@mulgrave.site> References: <201102091515.16202.bzolnier@gmail.com> <1297274408.3016.29.camel@mulgrave.site> <1297350456.4933.25.camel@mulgrave.site> Date: Fri, 11 Feb 2011 10:52:54 +0100 Message-ID: Subject: Re: [PATCH] scsi: make scsi_devinfo infrastructure optional From: Bartlomiej Zolnierkiewicz To: James Bottomley Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2493 Lines: 54 On Thu, Feb 10, 2011 at 4:07 PM, James Bottomley wrote: > On Thu, 2011-02-10 at 10:18 +0100, Bartlomiej Zolnierkiewicz wrote: >> On Wed, Feb 9, 2011 at 7:00 PM, James Bottomley wrote: >> > On Wed, 2011-02-09 at 15:15 +0100, Bartlomiej Zolnierkiewicz wrote: >> >> Add SCSI_QUIRKS config option (default y and dependent on EMBEDDED >> >> config option) to allow disabling of scsi_devinfo infrastructure. >> >> >> >> The output code size savings are ~14k for CONFIG_SCSI_QUIRKS=n >> >> (as measured on x86-32): >> > >> > I don't understand the point of this patch ... without the quirks SCSI >> > will do the wrong thing on a whole bunch of stuff. ?The savings look to >> > be tiny ... since the SCSI module is habitually a lot larger than your >> > figures suggest. >> >> The patch was originally done for embedded ATA-only setups. > > Well, if it's for ATA only then the better course would be extracting > libata from scsi. ?It's also a bit misleading to do sizings on x86, > because that doesn't imply embedded to me. ?Aren't there still ATAPI > devices that require the quirks? According to my knowledge all ATAPI quirks are handled locally in libata & sr. > Most embedded setups include some form of USB ... again, the pluggable > CD/DVD use the quirks table. This was done long time ago specifically for embedded 486-like embedded system w/o USB support and only using flash storage but indeed this is not a common case. > Given the potential for disaster even on embedded systems, I don't > really think something like this is a good idea. Well, I don't insist on applying it upstream as it is, it is more to show the direction where the possible room for improvements is in case of older/embedded systems and reducing memory/code size usage. [ There were some concerns about it during recent proposal to use more generalized code for support of some rare Intel-like PATA chipsets (which seem to cost ~20k as measured on x86-64 in terms of additional memory/code requirements, though most such systems are x86-32 only so the incurred cost is probably smaller) .] BTW with some effort we can do on-demand quirk table loading if it ever grows too big in the future. Thanks, Bartlomiej -- 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/