From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 1/2] mpt2sas: Remove acquisition of host_lock Date: Wed, 6 Apr 2011 09:45:55 -0400 Message-ID: <20110406134555.GA21729@infradead.org> References: <20110405214355.GQ4183@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:46750 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755896Ab1DFNp5 (ORCPT ); Wed, 6 Apr 2011 09:45:57 -0400 Content-Disposition: inline In-Reply-To: <20110405214355.GQ4183@linux.intel.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Matthew Wilcox Cc: linux-scsi@vger.kernel.org, DL-MPTFusionLinux@lsi.com On Tue, Apr 05, 2011 at 05:43:55PM -0400, Matthew Wilcox wrote: > > We can eliminate the use of the scsi command serial_number, as the race > that the driver is checking for cannot happen. > > Then the driver no longer needs to use the DEF_SCSI_QCMD() macro and no > longer acquires the host_lock. This improves performance substantially > on high-IOPS workloads. Looks fine. Note that this somehow clashes with my patch to simply remove the serial_number check from mpt2sas. We could just drop my smaller patch if this one gets in in a timely fashion.