[PATCH 6/8] fcoe: removes fcoe_watchdog

Robert Love
2009-05-06T17:52:46Z

From: Vasu Dev <vasu.dev@intel.com>

Removes periodic fcoe_watchdog timer used across all fcoe interface
maintained in fcoe_hostlist instead added new fcoe_queue_timer
per fcoe interface.

Added timer is armed only when some pending skb need to be flushed
as oppose to periodic 1 second fcoe_watchdog, since now
fcoe_queue_timer is used on demand thus set this to 2 jiffies.

Now fcoe_queue_timer is much simple than fcoe_watchdog using lock to
process all fcoe interface from fcoe_hostlist.

I noticed +ve performance result with using 2 jiffies timer as
this helps flushing fcoe_pending_queue quickly.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
---

drivers/scsi/fcoe/fcoe.c | 52 ++++++++++++++++------------------------------
drivers/scsi/fcoe/fcoe.h | 1 +
2 files changed, 19 insertions(+), 34 deletions(-)

diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 7d44a49..cf62e99 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -54,7 +54,6 @@ MODULE_LICENSE("GPL v2");
/* fcoe host list */
LIST_HEAD(fcoe_hostlist);
DEFINE_RWLOCK(fcoe_hostlist_lock);
-DEFINE_TIMER(fcoe_timer, NULL, 0, 0);
DEFINE_PER_CPU(struct fcoe_percpu_s, fcoe_percpu);

/* Function Prototypes */
@@ -167,6 +166,18 @@ static int fcoe_lport_config(struct fc_lport *lp)
}

/**
+ * fcoe_queue_timer() - fcoe queue timer
+ * @lp: the fc_lport pointer
+ *
+ * Calls fcoe_check_wait_queue on timeout
+ *
+ */
+static void fcoe_queue_timer(ulong lp)
+{
+ fcoe_check_wait_queue((struct fc_lport *)lp, NULL);
+}
+
+/**
* fcoe_netdev_config() - Set up netdev for SW FCoE
* @lp : ptr to the fc_lport
* @netdev : ptr to the associated netdevice struct
@@ -236,6 +247,7 @@ static int fcoe_netdev_config(struct fc_lport *lp, struct net_device *netdev)
}
skb_queue_head_init(&fc->fcoe_pending_queue);
fc->fcoe_pending_queue_active = 0;
+ setup_timer(&fc->timer, fcoe_queue_timer, (unsigned long)lp);

/* setup Source Mac Address */
memcpy(fc->ctlr.ctl_src_addr, fc->real_dev->dev_addr,
@@ -386,6 +398,9 @@ static int fcoe_if_destroy(struct net_device *netdev)
/* Free existing skbs */
fcoe_clean_pending_queue(lp);

+ /* Stop the timer */
+ del_timer_sync(&fc->timer);
+
/* Free memory used by statistical counters */
fc_lport_free_stats(lp);

@@ -1259,32 +1274,6 @@ int fcoe_percpu_receive_thread(void *arg)
}

/**
- * fcoe_watchdog() - fcoe timer callback
- * @vp:
- *
- * This checks the pending queue length for fcoe and set lport qfull
- * if the FCOE_MAX_QUEUE_DEPTH is reached. This is done for all fc_lport on the
- * fcoe_hostlist.
- *
- * Returns: 0 for success
- */
-void fcoe_watchdog(ulong vp)
-{
- struct fcoe_softc *fc;
-
- read_lock(&fcoe_hostlist_lock);
- list_for_each_entry(fc, &fcoe_hostlist, list) {
- if (fc->ctlr.lp)
- fcoe_check_wait_queue(fc->ctlr.lp, NULL);
- }
- read_unlock(&fcoe_hostlist_lock);
-
- fcoe_timer.expires = jiffies + (1 * HZ);
- add_timer(&fcoe_timer);
-}
-
-
-/**
* fcoe_check_wait_queue() - attempt to clear the transmit backlog
* @lp: the fc_lport
*
@@ -1332,6 +1321,8 @@ static void fcoe_check_wait_queue(struct fc_lport *lp, struct sk_buff *skb)

if (fc->fcoe_pending_queue.qlen < FCOE_LOW_QUEUE_DEPTH)
lp->qfull = 0;
+ if (fc->fcoe_pending_queue.qlen && !timer_pending(&fc->timer))
+ mod_timer(&fc->timer, jiffies + 2);
fc->fcoe_pending_queue_active = 0;
out:
if (fc->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
@@ -1808,10 +1799,6 @@ static int __init fcoe_init(void)
/* Setup link change notification */
fcoe_dev_setup();

- setup_timer(&fcoe_timer, fcoe_watchdog, 0);
-
- mod_timer(&fcoe_timer, jiffies + (10 * HZ));
-
fcoe_if_init();

return 0;
@@ -1837,9 +1824,6 @@ static void __exit fcoe_exit(void)

fcoe_dev_cleanup();

- /* Stop the timer */
- del_timer_sync(&fcoe_timer);
-
/* releases the associated fcoe hosts */
list_for_each_entry_safe(fc, tmp, &fcoe_hostlist, list)
fcoe_if_destroy(fc->real_dev);
diff --git a/drivers/scsi/fcoe/fcoe.h b/drivers/scsi/fcoe/fcoe.h
index 917aae8..a1eb8c1 100644
--- a/drivers/scsi/fcoe/fcoe.h
+++ b/drivers/scsi/fcoe/fcoe.h
@@ -61,6 +61,7 @@ struct fcoe_softc {
struct packet_type fip_packet_type;
struct sk_buff_head fcoe_pending_queue;
u8 fcoe_pending_queue_active;
+ struct timer_list timer; /* queue timer */
struct fcoe_ctlr ctlr;
};