Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751415AbdHEIoj (ORCPT ); Sat, 5 Aug 2017 04:44:39 -0400 Received: from verein.lst.de ([213.95.11.211]:33502 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751144AbdHEIoi (ORCPT ); Sat, 5 Aug 2017 04:44:38 -0400 Date: Sat, 5 Aug 2017 10:44:36 +0200 From: Christoph Hellwig To: "Richard W.M. Jones" Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , "Martin K. Petersen" , pbonzini@redhat.com Subject: Re: Increased memory usage with scsi-mq Message-ID: <20170805084436.GA14264@lst.de> References: <20170804210035.GA10017@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170804210035.GA10017@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 488 Lines: 11 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).