From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: Increased memory usage with scsi-mq Date: Sat, 5 Aug 2017 10:44:36 +0200 Message-ID: <20170805084436.GA14264@lst.de> References: <20170804210035.GA10017@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170804210035.GA10017@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: "Richard W.M. Jones" Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , "Martin K. Petersen" , pbonzini@redhat.com List-Id: linux-scsi@vger.kernel.org On Fri, Aug 04, 2017 at 10:00:47PM +0100, Richard W.M. Jones wrote: > I read your slides about scsi-mq and it seems like a significant > benefit to large machines, but could the out of the box defaults be > made more friendly for small memory machines? The default inumber of queues and queue depth and thus memory usage is set by the LLDD. Try to reduce the can_queue value in virtio_scsi and/or make sure you use the single queue variant in your VM (which should be tunable in qemu).