Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753427Ab3G2Lq7 (ORCPT ); Mon, 29 Jul 2013 07:46:59 -0400 Received: from mail-qe0-f41.google.com ([209.85.128.41]:37019 "EHLO mail-qe0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750821Ab3G2Lq5 (ORCPT ); Mon, 29 Jul 2013 07:46:57 -0400 Date: Mon, 29 Jul 2013 07:46:53 -0400 From: Tejun Heo To: "Nicholas A. Bellinger" Cc: Jens Axboe , Alexander Gordeev , James Bottomley , Mike Christie , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Jeff Garzik , linux-scsi Subject: Re: [PATCH RESEND 0/1] AHCI: Optimize interrupt processing Message-ID: <20130729114653.GB20951@mtj.dyndns.org> References: <1374215660.7397.1041.camel@haakon3.risingtidesystems.com> <1374248000.2266.20.camel@dabdike> <1374267684.7397.1058.camel@haakon3.risingtidesystems.com> <1374296162.7397.1098.camel@haakon3.risingtidesystems.com> <20130722150359.GA16564@dhcp-26-207.brq.redhat.com> <1374527436.7397.1145.camel@haakon3.risingtidesystems.com> <20130725101641.GB31994@dhcp-26-207.brq.redhat.com> <1374790082.7397.1411.camel@haakon3.risingtidesystems.com> <20130726020928.GL29296@kernel.dk> <1374873276.7397.1512.camel@haakon3.risingtidesystems.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1374873276.7397.1512.camel@haakon3.risingtidesystems.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1369 Lines: 31 Hello, On Fri, Jul 26, 2013 at 02:14:36PM -0700, Nicholas A. Bellinger wrote: > So I don't think (completely) getting rid of ata_port->qcmds[] will be > possible, and just converting the ata_scsi_queuecmd() path to use the > extra SHT->cmd_size pre-allocation for *ata_queued_cmd might end up > being more trouble that it's worth. Still undecided on that part.. > > Tejun, do you have any thoughts + input here..? libata exception handling which includes probing doesn't go through SCSI at all. It all works inside libata proper using ata_queuecmds and only the result is exposed to SCSI. Most of those SCSI semantics need to be emulated anyway, so this makes things a lot easier than going through SCSI for each command. As it currently stands, it'd be a lot of effort to try to embed ata_qc's into higher layer construct. Given how it's used, I don't think it's a high priority task. One thing which would probably be worthwhile tho is getting rid of the bitmap based qc tag allocator in libata. That one is just borderline stupid to keep around on any setup which is supposed to be scalable. Thanks. -- tejun -- 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/