Re: [dpdk-dev] [PATCH] net/mlx5: fix memory region cache init

["Xueming(Steven) Li" <xuemingl@mellanox.com>]

> -----Original Message-----
> From: Yongseok Koh
> Sent: Friday, May 25, 2018 6:20 PM
> To: Xueming(Steven) Li <xuemingl@mellanox.com>
> Cc: Shahaf Shuler <shahafs@mellanox.com>; dev@dpdk.org
> Subject: Re: [PATCH] net/mlx5: fix memory region cache init
> 
> > On May 24, 2018, at 11:35 PM, Xueming Li <xuemingl@mellanox.com> wrote:
> >
> > This patch moved MR cache init from device configuration function to
> > probe function to make sure init only once.
> >
> > Fixes: 974f1e7ef146 ("net/mlx5: add new memory region support")
> > Cc: yskoh@mellanox.com
> >
> > Signed-off-by: Xueming Li <xuemingl@mellanox.com>
> > ---
> > drivers/net/mlx5/mlx5.c        | 11 +++++++++++
> > drivers/net/mlx5/mlx5_ethdev.c | 11 -----------
> > drivers/net/mlx5/mlx5_mr.c     |  1 +
> > 3 files changed, 12 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c index
> > dae847493..77ed8e01f 100644
> > --- a/drivers/net/mlx5/mlx5.c
> > +++ b/drivers/net/mlx5/mlx5.c
> > @@ -1193,6 +1193,17 @@ mlx5_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
> > 			goto port_error;
> > 		}
> > 		priv->config.max_verbs_prio = verb_priorities;
> > +		/*
> > +		 * Once the device is added to the list of memory event
> > +		 * callback, its global MR cache table cannot be expanded
> > +		 * on the fly because of deadlock. If it overflows, lookup
> > +		 * should be done by searching MR list linearly, which is slow.
> > +		 */
> > +		err = -mlx5_mr_btree_init(&priv->mr.cache,
> > +					  MLX5_MR_BTREE_CACHE_N * 2,
> > +					  eth_dev->device->numa_node);
> > +		if (err)
> > +			goto port_error;
> 
> A nit.
> Like mlx5_flow_create_drop_queue(), please store rte_errno to err (err = rte_errno;) instead of
> putting a minus sign to the function.

Rte_errno is set inside mlx5_mr_btree_init() if any error, that's why I simply the code.

> 
> With that being fixed, you can put my acked-by tag when you submit v2.
> 
> Thanks,
> Yongseok
> 
> > 		/* Add device to memory callback list. */
> > 		rte_rwlock_write_lock(&mlx5_shared_data->mem_event_rwlock);
> > 		LIST_INSERT_HEAD(&mlx5_shared_data->mem_event_cb_list,
> > diff --git a/drivers/net/mlx5/mlx5_ethdev.c
> > b/drivers/net/mlx5/mlx5_ethdev.c index f6cebae41..90488af33 100644
> > --- a/drivers/net/mlx5/mlx5_ethdev.c
> > +++ b/drivers/net/mlx5/mlx5_ethdev.c
> > @@ -392,17 +392,6 @@ mlx5_dev_configure(struct rte_eth_dev *dev)
> > 		if (++j == rxqs_n)
> > 			j = 0;
> > 	}
> > -	/*
> > -	 * Once the device is added to the list of memory event callback, its
> > -	 * global MR cache table cannot be expanded on the fly because of
> > -	 * deadlock. If it overflows, lookup should be done by searching MR list
> > -	 * linearly, which is slow.
> > -	 */
> > -	if (mlx5_mr_btree_init(&priv->mr.cache, MLX5_MR_BTREE_CACHE_N * 2,
> > -			       dev->device->numa_node)) {
> > -		/* rte_errno is already set. */
> > -		return -rte_errno;
> > -	}
> > 	return 0;
> > }
> >
> > diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
> > index abb1f5179..08105a443 100644
> > --- a/drivers/net/mlx5/mlx5_mr.c
> > +++ b/drivers/net/mlx5/mlx5_mr.c
> > @@ -191,6 +191,7 @@ mlx5_mr_btree_init(struct mlx5_mr_btree *bt, int n, int socket)
> > 		rte_errno = EINVAL;
> > 		return -rte_errno;
> > 	}
> > +	assert(!bt->table && !bt->size);
> > 	memset(bt, 0, sizeof(*bt));
> > 	bt->table = rte_calloc_socket("B-tree table",
> > 				      n, sizeof(struct mlx5_mr_cache),
> > --
> > 2.13.3
> >