From: Dragos Tatulea Date: Fri, 30 Aug 2024 10:58:38 +0000 (+0300) Subject: vdpa/mlx5: Postpone MR deletion X-Git-Url: https://git.dujemihanovic.xyz/?a=commitdiff_plain;h=62111654481d5df4be3776a898cb88b5e4974103;p=linux.git vdpa/mlx5: Postpone MR deletion Currently, when a new MR is set up, the old MR is deleted. MR deletion is about 30-40% the time of MR creation. As deleting the old MR is not important for the process of setting up the new MR, this operation can be postponed. This series adds a workqueue that does MR garbage collection at a later point. If the MR lock is taken, the handler will back off and reschedule. The exception during shutdown: then the handler must not postpone the work. Note that this is only a speculative optimization: if there is some mapping operation that is triggered while the garbage collector handler has the lock taken, this operation it will have to wait for the handler to finish. Signed-off-by: Dragos Tatulea Reviewed-by: Cosmin Ratiu Message-Id: <20240830105838.2666587-9-dtatulea@nvidia.com> Signed-off-by: Michael S. Tsirkin --- diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h index c3e17bc888e8..2cedf7e2dbc4 100644 --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h @@ -86,8 +86,18 @@ enum { struct mlx5_vdpa_mr_resources { struct mlx5_vdpa_mr *mr[MLX5_VDPA_NUM_AS]; unsigned int group2asid[MLX5_VDPA_NUMVQ_GROUPS]; + + /* Pre-deletion mr list */ struct list_head mr_list_head; + + /* Deferred mr list */ + struct list_head mr_gc_list_head; + struct workqueue_struct *wq_gc; + struct delayed_work gc_dwork_ent; + struct mutex lock; + + atomic_t shutdown; }; struct mlx5_vdpa_dev { diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c index 64683a39d3db..2dd21e0b399e 100644 --- a/drivers/vdpa/mlx5/core/mr.c +++ b/drivers/vdpa/mlx5/core/mr.c @@ -653,14 +653,50 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_ kfree(mr); } +/* There can be multiple .set_map() operations in quick succession. + * This large delay is a simple way to prevent the MR cleanup from blocking + * .set_map() MR creation in this scenario. + */ +#define MLX5_VDPA_MR_GC_TRIGGER_MS 2000 + +static void mlx5_vdpa_mr_gc_handler(struct work_struct *work) +{ + struct mlx5_vdpa_mr_resources *mres; + struct mlx5_vdpa_mr *mr, *tmp; + struct mlx5_vdpa_dev *mvdev; + + mres = container_of(work, struct mlx5_vdpa_mr_resources, gc_dwork_ent.work); + + if (atomic_read(&mres->shutdown)) { + mutex_lock(&mres->lock); + } else if (!mutex_trylock(&mres->lock)) { + queue_delayed_work(mres->wq_gc, &mres->gc_dwork_ent, + msecs_to_jiffies(MLX5_VDPA_MR_GC_TRIGGER_MS)); + return; + } + + mvdev = container_of(mres, struct mlx5_vdpa_dev, mres); + + list_for_each_entry_safe(mr, tmp, &mres->mr_gc_list_head, mr_list) { + _mlx5_vdpa_destroy_mr(mvdev, mr); + } + + mutex_unlock(&mres->lock); +} + static void _mlx5_vdpa_put_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr) { + struct mlx5_vdpa_mr_resources *mres = &mvdev->mres; + if (!mr) return; - if (refcount_dec_and_test(&mr->refcount)) - _mlx5_vdpa_destroy_mr(mvdev, mr); + if (refcount_dec_and_test(&mr->refcount)) { + list_move_tail(&mr->mr_list, &mres->mr_gc_list_head); + queue_delayed_work(mres->wq_gc, &mres->gc_dwork_ent, + msecs_to_jiffies(MLX5_VDPA_MR_GC_TRIGGER_MS)); + } } void mlx5_vdpa_put_mr(struct mlx5_vdpa_dev *mvdev, @@ -851,9 +887,17 @@ int mlx5_vdpa_init_mr_resources(struct mlx5_vdpa_dev *mvdev) { struct mlx5_vdpa_mr_resources *mres = &mvdev->mres; - INIT_LIST_HEAD(&mres->mr_list_head); + mres->wq_gc = create_singlethread_workqueue("mlx5_vdpa_mr_gc"); + if (!mres->wq_gc) + return -ENOMEM; + + INIT_DELAYED_WORK(&mres->gc_dwork_ent, mlx5_vdpa_mr_gc_handler); + mutex_init(&mres->lock); + INIT_LIST_HEAD(&mres->mr_list_head); + INIT_LIST_HEAD(&mres->mr_gc_list_head); + return 0; } @@ -861,5 +905,10 @@ void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev) { struct mlx5_vdpa_mr_resources *mres = &mvdev->mres; + atomic_set(&mres->shutdown, 1); + + flush_delayed_work(&mres->gc_dwork_ent); + destroy_workqueue(mres->wq_gc); + mres->wq_gc = NULL; mutex_destroy(&mres->lock); } diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c index 4b7dcfcba444..dee019977716 100644 --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c @@ -3435,6 +3435,8 @@ static void mlx5_vdpa_free(struct vdpa_device *vdev) free_fixed_resources(ndev); mlx5_vdpa_clean_mrs(mvdev); mlx5_vdpa_destroy_mr_resources(&ndev->mvdev); + mlx5_cmd_cleanup_async_ctx(&mvdev->async_ctx); + if (!is_zero_ether_addr(ndev->config.mac)) { pfmdev = pci_get_drvdata(pci_physfn(mvdev->mdev->pdev)); mlx5_mpfs_del_mac(pfmdev, ndev->config.mac); @@ -4042,8 +4044,6 @@ static void mlx5_vdpa_dev_del(struct vdpa_mgmt_dev *v_mdev, struct vdpa_device * mvdev->wq = NULL; destroy_workqueue(wq); mgtdev->ndev = NULL; - - mlx5_cmd_cleanup_async_ctx(&mvdev->async_ctx); } static int mlx5_vdpa_set_attr(struct vdpa_mgmt_dev *v_mdev, struct vdpa_device *dev,