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net/mlx5e: Use kernel's mechanism to avoid missing NAPIs 

We used a channel state bit MLX5E_CHANNEL_NAPI_SCHED to make
sure no NAPI is missed when a channel's napi_schedule() is called
for completion events of the different channel's resources/rings
while NAPI is currently running.
Now, as similar mechanism is implemented in kernel,
("39e6c8208d7b net: solve a NAPI race"),
we obsolete our own implementation and rely on the return value
of napi_complete_done().

This patch removes a redundant overhead of atomic bit operations.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
This commit is contained in:
Tariq Toukan 2017-07-02 12:56:12 +03:00 committed by Saeed Mahameed
parent 29c2849e0d
commit 7b33aaeaae
3 changed files with 1 additions and 15 deletions
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5
drivers/net/ethernet/mellanox/mlx5/core/en.h
View File

@ -570,10 +570,6 @@ struct mlx5e_rq {
struct mlx5_core_mkey umr_mkey;
} ____cacheline_aligned_in_smp;
enum channel_flags {
MLX5E_CHANNEL_NAPI_SCHED = 1,
};
struct mlx5e_channel {
/* data path */
struct mlx5e_rq rq;
@ -585,7 +581,6 @@ struct mlx5e_channel {
struct net_device *netdev;
__be32 mkey_be;
u8 num_tc;
unsigned long flags;
/* control */
struct mlx5e_priv *priv;

1
drivers/net/ethernet/mellanox/mlx5/core/en_main.c
View File

@ -3697,7 +3697,6 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)
set_bit(MLX5E_RQ_STATE_ENABLED, &c->rq.state);
/* napi_schedule in case we have missed anything */
set_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags);
napi_schedule(&c->napi);
if (old_prog)

10
drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c
View File

@ -40,8 +40,6 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget)
int work_done;
int i;
clear_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags);
for (i = 0; i < c->num_tc; i++)
busy |= mlx5e_poll_tx_cq(&c->sq[i].cq, budget);
@ -56,13 +54,8 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget)
if (busy)
return budget;
napi_complete_done(napi, work_done);
/* avoid losing completion event during/after polling cqs */
if (test_bit(MLX5E_CHANNEL_NAPI_SCHED, &c->flags)) {
napi_schedule(napi);
if (unlikely(!napi_complete_done(napi, work_done)))
return work_done;
}
for (i = 0; i < c->num_tc; i++)
mlx5e_cq_arm(&c->sq[i].cq);
@ -81,7 +74,6 @@ void mlx5e_completion_event(struct mlx5_core_cq *mcq)
struct mlx5e_cq *cq = container_of(mcq, struct mlx5e_cq, mcq);
cq->event_ctr++;
set_bit(MLX5E_CHANNEL_NAPI_SCHED, &cq->channel->flags);
napi_schedule(cq->napi);
}