From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752022AbcG1Jbv (ORCPT ); Thu, 28 Jul 2016 05:31:51 -0400 Received: from smtp.citrix.com ([66.165.176.89]:53587 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752549AbcG1Jbn (ORCPT ); Thu, 28 Jul 2016 05:31:43 -0400 X-IronPort-AV: E=Sophos;i="5.28,433,1464652800"; d="scan'208";a="368920181" Subject: Re: [Xen-devel] [PATCH v3] xen-blkfront: dynamic configuration of per-vbd resources To: Bob Liu , References: <1469589685-31630-1-git-send-email-bob.liu@oracle.com> CC: , From: David Vrabel X-Enigmail-Draft-Status: N1110 Message-ID: <5799D0F6.2050107@citrix.com> Date: Thu, 28 Jul 2016 10:31:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.5.0 MIME-Version: 1.0 In-Reply-To: <1469589685-31630-1-git-send-email-bob.liu@oracle.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/07/16 04:21, Bob Liu wrote: > The current VBD layer reserves buffer space for each attached device based on > three statically configured settings which are read at boot time. > * max_indirect_segs: Maximum amount of segments. > * max_ring_page_order: Maximum order of pages to be used for the shared ring. > * max_queues: Maximum of queues(rings) to be used. I think you want a single knob for "maximum number of pages in flight". This is much easier for an admin to relate to resource usage. You could apply this limit without having to reconfigure, which would simplify this patch quite a bit. David