/**
* 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->@max_fill. If there is insufficient atomic
* 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.
*/
void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, bool atomic)
{
struct efx_nic *efx = rx_queue->efx;
unsigned int fill_level, batch_size;
int space, rc = 0;
if (!rx_queue->refill_enabled)
return;
/* 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 > rx_queue->efx->rxq_entries);
if (fill_level >= rx_queue->fast_fill_trigger)
goto out;
/* Record minimum fill level */
if (unlikely(fill_level < rx_queue->min_fill)) {
if (fill_level)
rx_queue->min_fill = fill_level;
}
batch_size = efx->rx_pages_per_batch * efx->rx_bufs_per_page;
space = rx_queue->max_fill - fill_level;
EFX_BUG_ON_PARANOID(space < batch_size);
netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
"RX queue %d fast-filling descriptor ring from"
" level %d to level %d\n",
efx_rx_queue_index(rx_queue), fill_level,
rx_queue->max_fill);
do {
rc = efx_init_rx_buffers(rx_queue, atomic);
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;
}
} while ((space -= batch_size) >= batch_size);
netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
"RX queue %d fast-filled descriptor ring "
"to level %d\n", efx_rx_queue_index(rx_queue),
rx_queue->added_count - rx_queue->removed_count);
out:
if (rx_queue->notified_count != rx_queue->added_count)
efx_nic_notify_rx_desc(rx_queue);
}
/**
* 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.
*/
static int __efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue,
int retry)
{
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.
*/
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;
/* Record minimum fill level */
if (unlikely(fill_level < rx_queue->min_fill)) {
if (fill_level)
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;
EFX_TRACE(rx_queue->efx, "RX queue %d fast-filling descriptor ring from"
" level %d to level %d using %s allocation\n",
rx_queue->queue, fill_level, rx_queue->fast_fill_limit,
rx_queue->channel->rx_alloc_push_pages ? "page" : "skb");
do {
for (i = 0; i < EFX_RX_BATCH; ++i) {
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))
goto out;
++rx_queue->added_count;
}
} while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
EFX_TRACE(rx_queue->efx, "RX queue %d fast-filled descriptor ring "
"to level %d\n", rx_queue->queue,
rx_queue->added_count - rx_queue->removed_count);
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;
}
