From patchwork Thu Oct 13 15:18:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Zhadchenko X-Patchwork-Id: 13006102 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAEB0C43219 for ; Thu, 13 Oct 2022 15:19:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229561AbiJMPTg (ORCPT ); Thu, 13 Oct 2022 11:19:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbiJMPTc (ORCPT ); Thu, 13 Oct 2022 11:19:32 -0400 Received: from relay.virtuozzo.com (relay.virtuozzo.com [130.117.225.111]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E6C611E45A for ; Thu, 13 Oct 2022 08:19:30 -0700 (PDT) Received: from dev006.ch-qa.sw.ru ([172.29.1.11]) by relay.virtuozzo.com with esmtp (Exim 4.95) (envelope-from ) id 1oizwM-00B3Aa-Jg; Thu, 13 Oct 2022 17:18:57 +0200 From: Andrey Zhadchenko To: virtualization@lists.linux-foundation.org Cc: andrey.zhadchenko@virtuozzo.com, mst@redhat.com, jasonwang@redhat.com, kvm@vger.kernel.org, stefanha@redhat.com, sgarzare@redhat.com, den@virtuozzo.com, ptikhomirov@virtuozzo.com Subject: [RFC PATCH v2 02/10] drivers/vhost: use array to store workers Date: Thu, 13 Oct 2022 18:18:31 +0300 Message-Id: <20221013151839.689700-3-andrey.zhadchenko@virtuozzo.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221013151839.689700-1-andrey.zhadchenko@virtuozzo.com> References: <20221013151839.689700-1-andrey.zhadchenko@virtuozzo.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org We want to support several vhost workers. The first step is to rework vhost to use array of workers rather than single pointer. Update creation and cleanup routines. Signed-off-by: Andrey Zhadchenko --- drivers/vhost/vhost.c | 75 +++++++++++++++++++++++++++++++------------ drivers/vhost/vhost.h | 10 +++++- 2 files changed, 63 insertions(+), 22 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 40097826cff0..40cc50c33c66 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -231,11 +231,24 @@ void vhost_poll_stop(struct vhost_poll *poll) } EXPORT_SYMBOL_GPL(vhost_poll_stop); +static void vhost_work_queue_at_worker(struct vhost_worker *w, + struct vhost_work *work) +{ + if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) { + /* We can only add the work to the list after we're + * sure it was not in the list. + * test_and_set_bit() implies a memory barrier. + */ + llist_add(&work->node, &w->work_list); + wake_up_process(w->worker); + } +} + void vhost_dev_flush(struct vhost_dev *dev) { struct vhost_flush_struct flush; - if (dev->worker) { + if (dev->workers[0].worker) { init_completion(&flush.wait_event); vhost_work_init(&flush.work, vhost_flush_work); @@ -247,17 +260,12 @@ EXPORT_SYMBOL_GPL(vhost_dev_flush); void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) { - if (!dev->worker) + struct vhost_worker *w = &dev->workers[0]; + + if (!w->worker) return; - if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) { - /* We can only add the work to the list after we're - * sure it was not in the list. - * test_and_set_bit() implies a memory barrier. - */ - llist_add(&work->node, &dev->work_list); - wake_up_process(dev->worker); - } + vhost_work_queue_at_worker(w, work); } EXPORT_SYMBOL_GPL(vhost_work_queue); @@ -333,9 +341,29 @@ static void vhost_vq_reset(struct vhost_dev *dev, __vhost_vq_meta_reset(vq); } +static void vhost_worker_reset(struct vhost_worker *w) +{ + init_llist_head(&w->work_list); + w->worker = NULL; +} + +void vhost_cleanup_workers(struct vhost_dev *dev) +{ + int i; + + for (i = 0; i < dev->nworkers; ++i) { + WARN_ON(!llist_empty(&dev->workers[i].work_list)); + kthread_stop(dev->workers[i].worker); + vhost_worker_reset(&dev->workers[i]); + } + + dev->nworkers = 0; +} + static int vhost_worker(void *data) { - struct vhost_dev *dev = data; + struct vhost_worker *w = data; + struct vhost_dev *dev = w->dev; struct vhost_work *work, *work_next; struct llist_node *node; @@ -350,7 +378,7 @@ static int vhost_worker(void *data) break; } - node = llist_del_all(&dev->work_list); + node = llist_del_all(&w->work_list); if (!node) schedule(); @@ -473,7 +501,6 @@ void vhost_dev_init(struct vhost_dev *dev, dev->umem = NULL; dev->iotlb = NULL; dev->mm = NULL; - dev->worker = NULL; dev->iov_limit = iov_limit; dev->weight = weight; dev->byte_weight = byte_weight; @@ -485,6 +512,11 @@ void vhost_dev_init(struct vhost_dev *dev, INIT_LIST_HEAD(&dev->pending_list); spin_lock_init(&dev->iotlb_lock); + dev->nworkers = 0; + for (i = 0; i < VHOST_MAX_WORKERS; ++i) { + dev->workers[i].dev = dev; + vhost_worker_reset(&dev->workers[i]); + } for (i = 0; i < dev->nvqs; ++i) { vq = dev->vqs[i]; @@ -594,7 +626,8 @@ long vhost_dev_set_owner(struct vhost_dev *dev) goto err_worker; } - dev->worker = worker; + dev->workers[0].worker = worker; + dev->nworkers = 1; wake_up_process(worker); /* avoid contributing to loadavg */ err = vhost_attach_cgroups(dev); @@ -608,9 +641,10 @@ long vhost_dev_set_owner(struct vhost_dev *dev) return 0; err_cgroup: - if (dev->worker) { - kthread_stop(dev->worker); - dev->worker = NULL; + dev->nworkers = 0; + if (dev->workers[0].worker) { + kthread_stop(dev->workers[0].worker); + dev->workers[0].worker = NULL; } err_worker: vhost_detach_mm(dev); @@ -693,6 +727,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx); vhost_vq_reset(dev, dev->vqs[i]); } + vhost_dev_free_iovecs(dev); if (dev->log_ctx) eventfd_ctx_put(dev->log_ctx); @@ -704,10 +739,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev) dev->iotlb = NULL; vhost_clear_msg(dev); wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); - WARN_ON(!llist_empty(&dev->work_list)); - if (dev->worker) { - kthread_stop(dev->worker); - dev->worker = NULL; + if (dev->use_worker) { + vhost_cleanup_workers(dev); dev->kcov_handle = 0; } vhost_detach_mm(dev); diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index d9109107af08..fc365b08fc38 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -25,6 +25,13 @@ struct vhost_work { unsigned long flags; }; +#define VHOST_MAX_WORKERS 4 +struct vhost_worker { + struct task_struct *worker; + struct llist_head work_list; + struct vhost_dev *dev; +}; + /* Poll a file (eventfd or socket) */ /* Note: there's nothing vhost specific about this structure. */ struct vhost_poll { @@ -148,7 +155,8 @@ struct vhost_dev { int nvqs; struct eventfd_ctx *log_ctx; struct llist_head work_list; - struct task_struct *worker; + struct vhost_worker workers[VHOST_MAX_WORKERS]; + int nworkers; struct vhost_iotlb *umem; struct vhost_iotlb *iotlb; spinlock_t iotlb_lock;