From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F21BC433F5 for ; Sun, 5 Sep 2021 07:46:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1565960F6D for ; Sun, 5 Sep 2021 07:46:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234942AbhIEHrj (ORCPT ); Sun, 5 Sep 2021 03:47:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:53184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229599AbhIEHrj (ORCPT ); Sun, 5 Sep 2021 03:47:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C849360555; Sun, 5 Sep 2021 07:46:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1630827996; bh=O/ZxP3FhOz37k0frdZmwLZpa5oBRB8mmxRGdut1wTDs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=l/n5ExtJ0lN140PPLg37CRQXuH3DT+TA3Oki8D+6E8+aoYkaeS3r68Rucy5CGcKbI mpp9ne8wEbkSqnLUxI2hGXfIdxTvYXYkEmfEUzPMGn3FYHzNmjmCkMLagls1eJqpRh wWVoCqII96pbG56Tt6e9mjtgw9QcVdTbs3hU5lGdOBJEibeq9n/uNR3xnormFYb1f9 9c2tNLosDtsYTePJ6Y/c+SXGfD/3uJd+SGXSS4LXw8O74bNXXqWleV9E7f79nzkw0C WCTE+4WdfdKFbLhkQFWG9TChM2kWIJXtPjkuCvV0gopzPjDXiG8Uqj5ItTWHdAr+Af THLmYI/iz//nA== Date: Sun, 5 Sep 2021 10:46:32 +0300 From: Leon Romanovsky To: Max Gurtovoy Cc: hch@infradead.org, mst@redhat.com, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, stefanha@redhat.com, israelr@nvidia.com, nitzanc@nvidia.com, oren@nvidia.com, linux-block@vger.kernel.org, axboe@kernel.dk Subject: Re: [PATCH v3 1/1] virtio-blk: add num_request_queues module parameter Message-ID: References: <20210902204622.54354-1-mgurtovoy@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210902204622.54354-1-mgurtovoy@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Sep 02, 2021 at 11:46:22PM +0300, Max Gurtovoy wrote: > Sometimes a user would like to control the amount of request queues to > be created for a block device. For example, for limiting the memory > footprint of virtio-blk devices. > > Reviewed-by: Christoph Hellwig > Reviewed-by: Stefan Hajnoczi > Signed-off-by: Max Gurtovoy > --- > > changes from v2: > - renamed num_io_queues to num_request_queues (from Stefan) > - added Reviewed-by signatures (from Stefan and Christoph) > > changes from v1: > - use param_set_uint_minmax (from Christoph) > - added "Should > 0" to module description > > Note: This commit apply on top of Jens's branch for-5.15/drivers > > --- > drivers/block/virtio_blk.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 4b49df2dfd23..aaa2833a4734 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -24,6 +24,23 @@ > /* The maximum number of sg elements that fit into a virtqueue */ > #define VIRTIO_BLK_MAX_SG_ELEMS 32768 > > +static int virtblk_queue_count_set(const char *val, > + const struct kernel_param *kp) > +{ > + return param_set_uint_minmax(val, kp, 1, nr_cpu_ids); > +} > + > +static const struct kernel_param_ops queue_count_ops = { > + .set = virtblk_queue_count_set, > + .get = param_get_uint, > +}; > + > +static unsigned int num_request_queues; > +module_param_cb(num_request_queues, &queue_count_ops, &num_request_queues, > + 0644); > +MODULE_PARM_DESC(num_request_queues, > + "Number of request queues to use for blk device. Should > 0"); > + Won't it limit all virtio block devices to the same limit? It is very common to see multiple virtio-blk devices on the same system and they probably need different limits. Thanks