[PATCH net-next 5/10] cxgb3: separate TX and RX reclaim handlers

From: Divy Le Ray
Date: Fri Mar 13 2009 - 03:16:19 EST


From: Divy Le Ray <divy@xxxxxxxxxxx>

Separate TX and RX reclaim handlers
Don't disable interrupts in RX reclaim handler.

Signed-off-by: Divy Le Ray <divy@xxxxxxxxxxx>
---

drivers/net/cxgb3/adapter.h | 1
drivers/net/cxgb3/sge.c | 128 ++++++++++++++++++++++++++++++-------------
2 files changed, 89 insertions(+), 40 deletions(-)

diff --git a/drivers/net/cxgb3/adapter.h b/drivers/net/cxgb3/adapter.h
index 95dce48..66ce456 100644
--- a/drivers/net/cxgb3/adapter.h
+++ b/drivers/net/cxgb3/adapter.h
@@ -197,6 +197,7 @@ struct sge_qset { /* an SGE queue set */
struct netdev_queue *tx_q; /* associated netdev TX queue */
unsigned long txq_stopped; /* which Tx queues are stopped */
struct timer_list tx_reclaim_timer; /* reclaims TX buffers */
+ struct timer_list rx_reclaim_timer; /* reclaims RX buffers */
unsigned long port_stats[SGE_PSTAT_MAX];
} ____cacheline_aligned;

diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index a482429..7d779d1 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -61,6 +61,7 @@
#define FL1_PG_ORDER (PAGE_SIZE > 8192 ? 0 : 1)

#define SGE_RX_DROP_THRES 16
+#define RX_RECLAIM_PERIOD (HZ/4)

/*
* Max number of Rx buffers we replenish at a time.
@@ -71,6 +72,8 @@
* frequently as Tx buffers are usually reclaimed by new Tx packets.
*/
#define TX_RECLAIM_PERIOD (HZ / 4)
+#define TX_RECLAIM_TIMER_CHUNK 64U
+#define TX_RECLAIM_CHUNK 16U

/* WR size in bytes */
#define WR_LEN (WR_FLITS * 8)
@@ -308,21 +311,25 @@ static void free_tx_desc(struct adapter *adapter, struct sge_txq *q,
* reclaim_completed_tx - reclaims completed Tx descriptors
* @adapter: the adapter
* @q: the Tx queue to reclaim completed descriptors from
+ * @chunk: maximum number of descriptors to reclaim
*
* Reclaims Tx descriptors that the SGE has indicated it has processed,
* and frees the associated buffers if possible. Called with the Tx
* queue's lock held.
*/
-static inline void reclaim_completed_tx(struct adapter *adapter,
- struct sge_txq *q)
+static inline unsigned int reclaim_completed_tx(struct adapter *adapter,
+ struct sge_txq *q,
+ unsigned int chunk)
{
unsigned int reclaim = q->processed - q->cleaned;

+ reclaim = min(chunk, reclaim);
if (reclaim) {
free_tx_desc(adapter, q, reclaim);
q->cleaned += reclaim;
q->in_use -= reclaim;
}
+ return q->processed - q->cleaned;
}

/**
@@ -601,6 +608,7 @@ static void t3_reset_qset(struct sge_qset *q)
memset(q->txq, 0, sizeof(struct sge_txq) * SGE_TXQ_PER_SET);
q->txq_stopped = 0;
q->tx_reclaim_timer.function = NULL; /* for t3_stop_sge_timers() */
+ q->rx_reclaim_timer.function = NULL;
q->lro_frag_tbl.nr_frags = q->lro_frag_tbl.len = 0;
}

@@ -1179,7 +1187,7 @@ int t3_eth_xmit(struct sk_buff *skb, struct net_device *dev)
txq = netdev_get_tx_queue(dev, qidx);

spin_lock(&q->lock);
- reclaim_completed_tx(adap, q);
+ reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);

credits = q->size - q->in_use;
ndesc = calc_tx_descs(skb);
@@ -1588,7 +1596,7 @@ static int ofld_xmit(struct adapter *adap, struct sge_txq *q,
unsigned int ndesc = calc_tx_descs_ofld(skb), pidx, gen;

spin_lock(&q->lock);
- again:reclaim_completed_tx(adap, q);
+again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);

ret = check_desc_avail(adap, q, skb, ndesc, TXQ_OFLD);
if (unlikely(ret)) {
@@ -1630,7 +1638,7 @@ static void restart_offloadq(unsigned long data)
struct adapter *adap = pi->adapter;

spin_lock(&q->lock);
- again:reclaim_completed_tx(adap, q);
+again: reclaim_completed_tx(adap, q, TX_RECLAIM_CHUNK);

while ((skb = skb_peek(&q->sendq)) != NULL) {
unsigned int gen, pidx;
@@ -2747,13 +2755,13 @@ void t3_sge_err_intr_handler(struct adapter *adapter)
}

/**
- * sge_timer_cb - perform periodic maintenance of an SGE qset
+ * sge_timer_tx - perform periodic maintenance of an SGE qset
* @data: the SGE queue set to maintain
*
* Runs periodically from a timer to perform maintenance of an SGE queue
* set. It performs two tasks:
*
- * a) Cleans up any completed Tx descriptors that may still be pending.
+ * Cleans up any completed Tx descriptors that may still be pending.
* Normal descriptor cleanup happens when new packets are added to a Tx
* queue so this timer is relatively infrequent and does any cleanup only
* if the Tx queue has not seen any new packets in a while. We make a
@@ -2763,51 +2771,87 @@ void t3_sge_err_intr_handler(struct adapter *adapter)
* up). Since control queues use immediate data exclusively we don't
* bother cleaning them up here.
*
- * b) Replenishes Rx queues that have run out due to memory shortage.
- * Normally new Rx buffers are added when existing ones are consumed but
- * when out of memory a queue can become empty. We try to add only a few
- * buffers here, the queue will be replenished fully as these new buffers
- * are used up if memory shortage has subsided.
*/
-static void sge_timer_cb(unsigned long data)
+static void sge_timer_tx(unsigned long data)
{
- spinlock_t *lock;
struct sge_qset *qs = (struct sge_qset *)data;
- struct adapter *adap = qs->adap;
+ struct port_info *pi = netdev_priv(qs->netdev);
+ struct adapter *adap = pi->adapter;
+ unsigned int tbd[SGE_TXQ_PER_SET] = {0, 0};
+ unsigned long next_period;

if (spin_trylock(&qs->txq[TXQ_ETH].lock)) {
- reclaim_completed_tx(adap, &qs->txq[TXQ_ETH]);
+ tbd[TXQ_ETH] = reclaim_completed_tx(adap, &qs->txq[TXQ_ETH],
+ TX_RECLAIM_TIMER_CHUNK);
spin_unlock(&qs->txq[TXQ_ETH].lock);
}
if (spin_trylock(&qs->txq[TXQ_OFLD].lock)) {
- reclaim_completed_tx(adap, &qs->txq[TXQ_OFLD]);
+ tbd[TXQ_OFLD] = reclaim_completed_tx(adap, &qs->txq[TXQ_OFLD],
+ TX_RECLAIM_TIMER_CHUNK);
spin_unlock(&qs->txq[TXQ_OFLD].lock);
}
- lock = (adap->flags & USING_MSIX) ? &qs->rspq.lock :
- &adap->sge.qs[0].rspq.lock;
- if (spin_trylock_irq(lock)) {
- if (!napi_is_scheduled(&qs->napi)) {
- u32 status = t3_read_reg(adap, A_SG_RSPQ_FL_STATUS);
-
- if (qs->fl[0].credits < qs->fl[0].size)
- __refill_fl(adap, &qs->fl[0]);
- if (qs->fl[1].credits < qs->fl[1].size)
- __refill_fl(adap, &qs->fl[1]);
-
- if (status & (1 << qs->rspq.cntxt_id)) {
- qs->rspq.starved++;
- if (qs->rspq.credits) {
- refill_rspq(adap, &qs->rspq, 1);
- qs->rspq.credits--;
- qs->rspq.restarted++;
- t3_write_reg(adap, A_SG_RSPQ_FL_STATUS,
- 1 << qs->rspq.cntxt_id);
- }
+
+ next_period = TX_RECLAIM_PERIOD >>
+ (max(tbd[TXQ_ETH], tbd[TXQ_OFLD]) /
+ TX_RECLAIM_TIMER_CHUNK);
+ mod_timer(&qs->tx_reclaim_timer, jiffies + next_period);
+}
+
+/*
+ * sge_timer_rx - perform periodic maintenance of an SGE qset
+ * @data: the SGE queue set to maintain
+ *
+ * a) Replenishes Rx queues that have run out due to memory shortage.
+ * Normally new Rx buffers are added when existing ones are consumed but
+ * when out of memory a queue can become empty. We try to add only a few
+ * buffers here, the queue will be replenished fully as these new buffers
+ * are used up if memory shortage has subsided.
+ *
+ * b) Return coalesced response queue credits in case a response queue is
+ * starved.
+ *
+ */
+static void sge_timer_rx(unsigned long data)
+{
+ spinlock_t *lock;
+ struct sge_qset *qs = (struct sge_qset *)data;
+ struct port_info *pi = netdev_priv(qs->netdev);
+ struct adapter *adap = pi->adapter;
+ u32 status;
+
+ lock = adap->params.rev > 0 ?
+ &qs->rspq.lock : &adap->sge.qs[0].rspq.lock;
+
+ if (!spin_trylock_irq(lock))
+ goto out;
+
+ if (napi_is_scheduled(&qs->napi))
+ goto unlock;
+
+ if (adap->params.rev < 4) {
+ status = t3_read_reg(adap, A_SG_RSPQ_FL_STATUS);
+
+ if (status & (1 << qs->rspq.cntxt_id)) {
+ qs->rspq.starved++;
+ if (qs->rspq.credits) {
+ qs->rspq.credits--;
+ refill_rspq(adap, &qs->rspq, 1);
+ qs->rspq.restarted++;
+ t3_write_reg(adap, A_SG_RSPQ_FL_STATUS,
+ 1 << qs->rspq.cntxt_id);
}
}
- spin_unlock_irq(lock);
}
- mod_timer(&qs->tx_reclaim_timer, jiffies + TX_RECLAIM_PERIOD);
+
+ if (qs->fl[0].credits < qs->fl[0].size)
+ __refill_fl(adap, &qs->fl[0]);
+ if (qs->fl[1].credits < qs->fl[1].size)
+ __refill_fl(adap, &qs->fl[1]);
+
+unlock:
+ spin_unlock_irq(lock);
+out:
+ mod_timer(&qs->rx_reclaim_timer, jiffies + RX_RECLAIM_PERIOD);
}

/**
@@ -2850,7 +2894,8 @@ int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
struct sge_qset *q = &adapter->sge.qs[id];

init_qset_cntxt(q, id);
- setup_timer(&q->tx_reclaim_timer, sge_timer_cb, (unsigned long)q);
+ setup_timer(&q->tx_reclaim_timer, sge_timer_tx, (unsigned long)q);
+ setup_timer(&q->rx_reclaim_timer, sge_timer_rx, (unsigned long)q);

q->fl[0].desc = alloc_ring(adapter->pdev, p->fl_size,
sizeof(struct rx_desc),
@@ -2999,6 +3044,7 @@ int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
V_NEWTIMER(q->rspq.holdoff_tmr));

mod_timer(&q->tx_reclaim_timer, jiffies + TX_RECLAIM_PERIOD);
+ mod_timer(&q->rx_reclaim_timer, jiffies + RX_RECLAIM_PERIOD);

return 0;

@@ -3024,6 +3070,8 @@ void t3_stop_sge_timers(struct adapter *adap)

if (q->tx_reclaim_timer.function)
del_timer_sync(&q->tx_reclaim_timer);
+ if (q->rx_reclaim_timer.function)
+ del_timer_sync(&q->rx_reclaim_timer);
}
}


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