From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 03/13] scsi: unify allocation of scsi command and sense buffer Date: Mon, 25 May 2009 12:49:08 +0200 Message-ID: <20090525104908.GV11363@kernel.dk> References: <1243236668-3398-1-git-send-email-jens.axboe@oracle.com> <1243236668-3398-6-git-send-email-jens.axboe@oracle.com> <20090525074124.GA31746@infradead.org> <20090525074647.GK11363@kernel.dk> <20090525075008.GA23413@infradead.org> <4A1A7406.5060106@panasas.com> <20090525104215.GA3191@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Boaz Harrosh , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, chris.mason@oracle.com, david@fromorbit.com, akpm@linux-foundation.org, jack@suse.cz, yanmin_zhang@linux.intel.com, linux-scsi@vger.kernel.org, Matthew Wilcox , Andi Kleen , James Bottomley To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20090525104215.GA3191@infradead.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Mon, May 25 2009, Christoph Hellwig wrote: > On Mon, May 25, 2009 at 01:33:42PM +0300, Boaz Harrosh wrote: > > 1. If we have a machine with few type of hosts active each with it's own > > cmnd_slab we end up with many more slabs then today. Even though at the > > end they all happen to be of the same size. (With the pool reserves it > > can get big also). > > Note that this should be optional. Device not having their own > per-command structure would continue using the global pools. Those > that have their own per-command structures already have their own pools > anyway. The multiple pools of the same size "issue" can also easily be resolved by having SCSI provide a way to setup/destroy these pools. Then it can just reuse an existing pool, if it has the same size. However, I doubt that this is really a real life issue that's worth worrying about. -- Jens Axboe