sdp: rx_irq should use tasklet instead of timer due to latency issue

mod_timer(..., 0) measured to add 4ms delay.

Signed-off-by: Eldad Zinger <eldadz@mellanox.co.il>

diff --git a/drivers/infiniband/ulp/sdp/sdp.h b/drivers/infiniband/ulp/sdp/sdp.h
index 1cab58c3fc5629f151d2a167a2adf28469e6f4f9..2fc4f8f61830bbf20f17dd2faa2750eef3b9c0e1 100644 (file)
--- a/drivers/infiniband/ulp/sdp/sdp.h
+++ b/drivers/infiniband/ulp/sdp/sdp.h
@@ -322,6 +322,7 @@ struct sdp_rx_ring {
        spinlock_t       lock;
 
        struct timer_list       timer;
+       struct tasklet_struct   tasklet;
 };
 
 struct sdp_device {

diff --git a/drivers/infiniband/ulp/sdp/sdp_rx.c b/drivers/infiniband/ulp/sdp/sdp_rx.c
index 8b12cf04e8e663816f0544f69c056cd230aa857f..abe11e4a7dff921d8ed6544a5a031e6f83075103 100644 (file)
--- a/drivers/infiniband/ulp/sdp/sdp_rx.c
+++ b/drivers/infiniband/ulp/sdp/sdp_rx.c
@@ -833,7 +833,10 @@ static void sdp_rx_irq(struct ib_cq *cq, void *cq_context)
 
        sdp_prf(sk, NULL, "rx irq");
 
-       mod_timer(&ssk->rx_ring.timer, 0);
+       /* We could use rx_ring.timer instead, but mod_timer(..., 0)
+        * measured to add 4ms delay.
+        */
+       tasklet_hi_schedule(&ssk->rx_ring.tasklet);
 }
 
 static inline int sdp_should_rearm(struct sock *sk)
@@ -969,7 +972,8 @@ int sdp_rx_ring_create(struct sdp_sock *ssk, struct ib_device *device)
        INIT_WORK(&ssk->rx_comp_work, sdp_rx_comp_work);
        ssk->rx_ring.timer.function = sdp_process_rx_timer;
        ssk->rx_ring.timer.data = (unsigned long) ssk;
-
+       tasklet_init(&ssk->rx_ring.tasklet, sdp_process_rx_timer,
+                       (unsigned long) ssk);
        sdp_arm_rx_cq(&ssk->isk.sk);
 
        return 0;
@@ -1000,10 +1004,11 @@ void sdp_rx_ring_destroy(struct sdp_sock *ssk)
                }
        }
 
-       /* the timer should be deleted only after the rx_cq is destroyed,
-        * so there won't be rx_irq any more, meaning the timer will never be
+       /* the tasklet should be killed only after the rx_cq is destroyed,
+        * so there won't be rx_irq any more, meaning the tasklet will never be
         * enabled. */
        del_timer_sync(&ssk->rx_ring.timer);
+       tasklet_kill(&ssk->rx_ring.tasklet);
 
        SDP_WARN_ON(ring_head(ssk->rx_ring) != ring_tail(ssk->rx_ring));
 }