/**
* efx_fast_push_rx_descriptors - push new RX descriptors quickly
* @rx_queue: RX descriptor queue
- * @retry: Recheck the fill level
* This will aim to fill the RX descriptor queue up to
* @rx_queue->@fast_fill_limit. If there is insufficient atomic
- * memory to do so, the caller should retry.
+ * memory to do so, a slow fill will be scheduled.
+ *
+ * The caller must provide serialisation (none is used here). In practise,
+ * this means this function must run from the NAPI handler, or be called
+ * when NAPI is disabled.
*/
-static int __efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue,
- int retry)
+void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
{
struct efx_rx_buffer *rx_buf;
unsigned fill_level, index;
int i, space, rc = 0;
- /* Calculate current fill level. Do this outside the lock,
- * because most of the time we'll end up not wanting to do the
- * fill anyway.
- */
+ /* Calculate current fill level, and exit if we don't need to fill */
fill_level = (rx_queue->added_count - rx_queue->removed_count);
EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE);
-
- /* Don't fill if we don't need to */
if (fill_level >= rx_queue->fast_fill_trigger)
- return 0;
+ return;
/* Record minimum fill level */
if (unlikely(fill_level < rx_queue->min_fill)) {
rx_queue->min_fill = fill_level;
}
- /* Acquire RX add lock. If this lock is contended, then a fast
- * fill must already be in progress (e.g. in the refill
- * tasklet), so we don't need to do anything
- */
- if (!spin_trylock_bh(&rx_queue->add_lock))
- return -1;
-
- retry:
- /* Recalculate current fill level now that we have the lock */
- fill_level = (rx_queue->added_count - rx_queue->removed_count);
- EFX_BUG_ON_PARANOID(fill_level > EFX_RXQ_SIZE);
space = rx_queue->fast_fill_limit - fill_level;
if (space < EFX_RX_BATCH)
- goto out_unlock;
+ return;
EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
" level %d to level %d using %s allocation\n",
index = rx_queue->added_count & EFX_RXQ_MASK;
rx_buf = efx_rx_buffer(rx_queue, index);
rc = efx_init_rx_buffer(rx_queue, rx_buf);
- if (unlikely(rc))
+ if (unlikely(rc)) {
+ /* Ensure that we don't leave the rx queue
+ * empty */
+ if (rx_queue->added_count == rx_queue->removed_count)
+ efx_schedule_slow_fill(rx_queue);
goto out;
+ }
++rx_queue->added_count;
}
} while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
out:
/* Send write pointer to card. */
efx_nic_notify_rx_desc(rx_queue);
-
- /* If the fast fill is running inside from the refill tasklet, then
- * for SMP systems it may be running on a different CPU to
- * RX event processing, which means that the fill level may now be
- * out of date. */
- if (unlikely(retry && (rc == 0)))
- goto retry;
-
- out_unlock:
- spin_unlock_bh(&rx_queue->add_lock);
-
- return rc;
}
-/**
- * efx_fast_push_rx_descriptors - push new RX descriptors quickly
- * @rx_queue: RX descriptor queue
- *
- * This will aim to fill the RX descriptor queue up to
- * @rx_queue->@fast_fill_limit. If there is insufficient memory to do so,
- * it will schedule a work item to immediately continue the fast fill
- */
-void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
-{
- int rc;
-
- rc = __efx_fast_push_rx_descriptors(rx_queue, 0);
- if (unlikely(rc)) {
- /* Schedule the work item to run immediately. The hope is
- * that work is immediately pending to free some memory
- * (e.g. an RX event or TX completion)
- */
- efx_schedule_slow_fill(rx_queue, 0);
- }
-}
-
-void efx_rx_work(struct work_struct *data)
+void efx_rx_slow_fill(unsigned long context)
{
- struct efx_rx_queue *rx_queue;
- int rc;
-
- rx_queue = container_of(data, struct efx_rx_queue, work.work);
-
- if (unlikely(!rx_queue->channel->enabled))
- return;
-
- EFX_TRACE(rx_queue->efx, "RX queue %d worker thread executing on CPU "
- "%d\n", rx_queue->queue, raw_smp_processor_id());
+ struct efx_rx_queue *rx_queue = (struct efx_rx_queue *)context;
+ struct efx_channel *channel = rx_queue->channel;
+ /* Post an event to cause NAPI to run and refill the queue */
+ efx_nic_generate_fill_event(channel);
++rx_queue->slow_fill_count;
- /* Push new RX descriptors, allowing at least 1 jiffy for
- * the kernel to free some more memory. */
- rc = __efx_fast_push_rx_descriptors(rx_queue, 1);
- if (rc)
- efx_schedule_slow_fill(rx_queue, 1);
}
static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
EFX_LOG(rx_queue->efx, "shutting down RX queue %d\n", rx_queue->queue);
+ del_timer_sync(&rx_queue->slow_fill);
efx_nic_fini_rx(rx_queue);
/* Release RX buffers NB start at index 0 not current HW ptr */
git.openpandora.org / pandora-kernel.git / blobdiff