From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] libata error handling fixes (ATAPI) Date: Wed, 16 Nov 2005 08:23:49 -0500 Message-ID: <437B32E5.5030707@pobox.com> References: <20051114195717.GA24373@havoc.gtf.org> <20051115074148.GA17459@htj.dyndns.org> <4379AA5B.1060900@pobox.com> <4379B28E.9070708@gmail.com> <4379C062.3010302@pobox.com> <20051115120016.GD7787@suse.de> <437A2814.1060308@cs.wisc.edu> <20051115184131.GJ7787@suse.de> <20051116124035.GX7787@suse.de> <437B2C61.7080605@pobox.com> <20051116131333.GA7787@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.dvmed.net ([216.237.124.58]:51891 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1030321AbVKPNYD (ORCPT ); Wed, 16 Nov 2005 08:24:03 -0500 In-Reply-To: <20051116131333.GA7787@suse.de> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jens Axboe Cc: Mike Christie , Tejun Heo , linux-ide@vger.kernel.org, lkml , SCSI Mailing List Jens Axboe wrote: > On Wed, Nov 16 2005, Jeff Garzik wrote: > >>Jens Axboe wrote: >> >>>I updated that patch, and converted IDE and SCSI to use it. See the >>>results here: >>> >>>http://brick.kernel.dk/git/?p=linux-2.6-block.git;a=shortlog;h=blk-softirq >>> >>>The main change from the version posted last october is killing the >>>'slightly' overdesigned completion queue hashing. >> >>Nifty, I like. Comments: >> >>* use of spin_lock_irq() in all completion paths now makes me nervous. > > > Should be fine from the paths originating from blk_done_softirq(), as we > know interrupts are enabled in the first place. But generally I agree, > whenever in doubt always always use the irq saving variants. > > >>* certainly it's what SCSI does now, but is a softirq really necessary? >> Using a tasklet would kill all that per-cpu code, and notifier. > > > It would work fine with a tasklet of course, but it's going to generate > a _lot_ of traffic on io busy systems so I felt a dedicated softirq was > the way to go. fair enough. ACK. Jeff