Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752697AbdHJPkb (ORCPT ); Thu, 10 Aug 2017 11:40:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37098 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752495AbdHJPk3 (ORCPT ); Thu, 10 Aug 2017 11:40:29 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 82152C014196 Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=rjones@redhat.com Date: Thu, 10 Aug 2017 16:40:11 +0100 From: "Richard W.M. Jones" To: Paolo Bonzini Cc: Christoph Hellwig , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, "Martin K. Petersen" Subject: Re: Increased memory usage with scsi-mq Message-ID: <20170810154011.GB20914@redhat.com> References: <20170805155103.GE20914@redhat.com> <20170807122701.GH20914@redhat.com> <20170809160111.GC3141@lst.de> <3b96a6c9-c5af-c50d-ba02-59863d1ee5f2@redhat.com> <20170810122232.GY20914@redhat.com> <63c286cb-4720-33a7-5fcd-e7591cd6dd2c@redhat.com> <20170810141634.GA20914@redhat.com> <367767f5-b3b2-6905-759d-d97196e7f140@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <367767f5-b3b2-6905-759d-d97196e7f140@redhat.com> User-Agent: Mutt/1.5.20 (2009-12-10) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 10 Aug 2017 15:40:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4072 Lines: 107 OK this is looking a bit better now. With scsi-mq enabled: 175 disks virtqueue_size=64: 318 disks * virtqueue_size=16: 775 disks * With scsi-mq disabled: 1755 disks * = new results I also ran the whole libguestfs test suite with virtqueue_size=16 (with no failures shown). As this tests many different disk I/O operations, it gives me some confidence that things generally work. Do you have any other comments about the patches? I'm not sure I know enough to write an intelligent commit message for the kernel patch. Rich. --- kernel patch --- diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 9be211d68b15..d6b4ff634c0d 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -972,6 +972,8 @@ static int virtscsi_probe(struct virtio_device *vdev) if (err) goto virtscsi_init_failed; + shost->can_queue = virtqueue_get_vring_size(vscsi->req_vqs[0].vq); + cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1; shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue); shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF; diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 5e1b548828e6..2d7509da9f39 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -296,7 +296,6 @@ static inline int virtqueue_add(struct virtqueue *_vq, } #endif - BUG_ON(total_sg > vq->vring.num); BUG_ON(total_sg == 0); head = vq->free_head; @@ -305,8 +304,10 @@ static inline int virtqueue_add(struct virtqueue *_vq, * buffers, then go indirect. FIXME: tune this threshold */ if (vq->indirect && total_sg > 1 && vq->vq.num_free) desc = alloc_indirect(_vq, total_sg, gfp); - else + else { desc = NULL; + WARN_ON_ONCE(total_sg > vq->vring.num && !vq->indirect); + } if (desc) { /* Use a single buffer which doesn't continue */ --- qemu patch --- diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index eb639442d1..aadd99aad1 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -867,10 +867,10 @@ void virtio_scsi_common_realize(DeviceState *dev, s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE; s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE; - s->ctrl_vq = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE, ctrl); - s->event_vq = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE, evt); + s->ctrl_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, ctrl); + s->event_vq = virtio_add_queue(vdev, s->conf.virtqueue_size, evt); for (i = 0; i < s->conf.num_queues; i++) { - s->cmd_vqs[i] = virtio_add_queue(vdev, VIRTIO_SCSI_VQ_SIZE, cmd); + s->cmd_vqs[i] = virtio_add_queue(vdev, s->conf.virtqueue_size, cmd); } } @@ -917,6 +917,7 @@ static void virtio_scsi_device_unrealize(DeviceState *dev, Error **errp) static Property virtio_scsi_properties[] = { DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1), + DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI, parent_obj.conf.virtqueue_size, 128), DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors, 0xFFFF), DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun, diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h index de6ae5a9f6..e30a92d3e7 100644 --- a/include/hw/virtio/virtio-scsi.h +++ b/include/hw/virtio/virtio-scsi.h @@ -48,6 +48,7 @@ typedef struct virtio_scsi_config VirtIOSCSIConfig; struct VirtIOSCSIConf { uint32_t num_queues; + uint32_t virtqueue_size; uint32_t max_sectors; uint32_t cmd_per_lun; #ifdef CONFIG_VHOST_SCSI -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top