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Message-Id: <1259201395.2806.17.camel@achroite.uk.solarflarecom.com>
Date: Thu, 26 Nov 2009 02:09:55 +0000
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, linux-net-drivers@...arflare.com
Subject: [PATCH 07/16] sfc: Fix bugs in RX queue flushing
Avoid overrunning the hardware limit of 4 concurrent RX queue flushes.
Expand the queue flush state to support this. Make similar changes to
TX flushing to keep the code symmetric.
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/falcon.c | 103 ++++++++++++++++++++++++++----------------
drivers/net/sfc/net_driver.h | 11 ++++-
2 files changed, 73 insertions(+), 41 deletions(-)
diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index 2f1f1fc..e1b9ce3 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -109,6 +109,9 @@ MODULE_PARM_DESC(rx_xon_thresh_bytes, "RX fifo XON threshold");
/* Size and alignment of special buffers (4KB) */
#define FALCON_BUF_SIZE 4096
+/* Depth of RX flush request fifo */
+#define FALCON_RX_FLUSH_COUNT 4
+
#define FALCON_IS_DUAL_FUNC(efx) \
(falcon_rev(efx) < FALCON_REV_B0)
@@ -426,7 +429,7 @@ void falcon_init_tx(struct efx_tx_queue *tx_queue)
efx_oword_t tx_desc_ptr;
struct efx_nic *efx = tx_queue->efx;
- tx_queue->flushed = false;
+ tx_queue->flushed = FLUSH_NONE;
/* Pin TX descriptor ring */
falcon_init_special_buffer(efx, &tx_queue->txd);
@@ -476,6 +479,8 @@ static void falcon_flush_tx_queue(struct efx_tx_queue *tx_queue)
struct efx_nic *efx = tx_queue->efx;
efx_oword_t tx_flush_descq;
+ tx_queue->flushed = FLUSH_PENDING;
+
/* Post a flush command */
EFX_POPULATE_OWORD_2(tx_flush_descq,
FRF_AZ_TX_FLUSH_DESCQ_CMD, 1,
@@ -489,7 +494,7 @@ void falcon_fini_tx(struct efx_tx_queue *tx_queue)
efx_oword_t tx_desc_ptr;
/* The queue should have been flushed */
- WARN_ON(!tx_queue->flushed);
+ WARN_ON(tx_queue->flushed != FLUSH_DONE);
/* Remove TX descriptor ring from card */
EFX_ZERO_OWORD(tx_desc_ptr);
@@ -578,7 +583,7 @@ void falcon_init_rx(struct efx_rx_queue *rx_queue)
rx_queue->queue, rx_queue->rxd.index,
rx_queue->rxd.index + rx_queue->rxd.entries - 1);
- rx_queue->flushed = false;
+ rx_queue->flushed = FLUSH_NONE;
/* Pin RX descriptor ring */
falcon_init_special_buffer(efx, &rx_queue->rxd);
@@ -607,6 +612,8 @@ static void falcon_flush_rx_queue(struct efx_rx_queue *rx_queue)
struct efx_nic *efx = rx_queue->efx;
efx_oword_t rx_flush_descq;
+ rx_queue->flushed = FLUSH_PENDING;
+
/* Post a flush command */
EFX_POPULATE_OWORD_2(rx_flush_descq,
FRF_AZ_RX_FLUSH_DESCQ_CMD, 1,
@@ -620,7 +627,7 @@ void falcon_fini_rx(struct efx_rx_queue *rx_queue)
struct efx_nic *efx = rx_queue->efx;
/* The queue should already have been flushed */
- WARN_ON(!rx_queue->flushed);
+ WARN_ON(rx_queue->flushed != FLUSH_DONE);
/* Remove RX descriptor ring from card */
EFX_ZERO_OWORD(rx_desc_ptr);
@@ -1181,7 +1188,7 @@ static void falcon_poll_flush_events(struct efx_nic *efx)
FSF_AZ_DRIVER_EV_SUBDATA);
if (ev_queue < EFX_TX_QUEUE_COUNT) {
tx_queue = efx->tx_queue + ev_queue;
- tx_queue->flushed = true;
+ tx_queue->flushed = FLUSH_DONE;
}
} else if (ev_code == FSE_AZ_EV_CODE_DRIVER_EV &&
ev_sub_code == FSE_AZ_RX_DESCQ_FLS_DONE_EV) {
@@ -1191,17 +1198,29 @@ static void falcon_poll_flush_events(struct efx_nic *efx)
*event, FSF_AZ_DRIVER_EV_RX_FLUSH_FAIL);
if (ev_queue < efx->n_rx_queues) {
rx_queue = efx->rx_queue + ev_queue;
-
- /* retry the rx flush */
- if (ev_failed)
- falcon_flush_rx_queue(rx_queue);
- else
- rx_queue->flushed = true;
+ rx_queue->flushed =
+ ev_failed ? FLUSH_FAILED : FLUSH_DONE;
}
}
+ /* We're about to destroy the queue anyway, so
+ * it's ok to throw away every non-flush event */
+ EFX_SET_QWORD(*event);
+
read_ptr = (read_ptr + 1) & EFX_EVQ_MASK;
} while (read_ptr != end_ptr);
+
+ channel->eventq_read_ptr = read_ptr;
+}
+
+static void falcon_prepare_flush(struct efx_nic *efx)
+{
+ falcon_deconfigure_mac_wrapper(efx);
+
+ /* Wait for the tx and rx fifo's to get to the next packet boundary
+ * (~1ms without back-pressure), then to drain the remainder of the
+ * fifo's at data path speeds (negligible), with a healthy margin. */
+ msleep(10);
}
/* Handle tx and rx flushes at the same time, since they run in
@@ -1211,50 +1230,56 @@ int falcon_flush_queues(struct efx_nic *efx)
{
struct efx_rx_queue *rx_queue;
struct efx_tx_queue *tx_queue;
- int i;
- bool outstanding;
+ int i, tx_pending, rx_pending;
- /* Issue flush requests */
- efx_for_each_tx_queue(tx_queue, efx) {
- tx_queue->flushed = false;
+ falcon_prepare_flush(efx);
+
+ /* Flush all tx queues in parallel */
+ efx_for_each_tx_queue(tx_queue, efx)
falcon_flush_tx_queue(tx_queue);
- }
- efx_for_each_rx_queue(rx_queue, efx) {
- rx_queue->flushed = false;
- falcon_flush_rx_queue(rx_queue);
- }
- /* Poll the evq looking for flush completions. Since we're not pushing
- * any more rx or tx descriptors at this point, we're in no danger of
- * overflowing the evq whilst we wait */
+ /* The hardware supports four concurrent rx flushes, each of which may
+ * need to be retried if there is an outstanding descriptor fetch */
for (i = 0; i < FALCON_FLUSH_POLL_COUNT; ++i) {
- msleep(FALCON_FLUSH_INTERVAL);
- falcon_poll_flush_events(efx);
+ rx_pending = tx_pending = 0;
+ efx_for_each_rx_queue(rx_queue, efx) {
+ if (rx_queue->flushed == FLUSH_PENDING)
+ ++rx_pending;
+ }
+ efx_for_each_rx_queue(rx_queue, efx) {
+ if (rx_pending == FALCON_RX_FLUSH_COUNT)
+ break;
+ if (rx_queue->flushed == FLUSH_FAILED ||
+ rx_queue->flushed == FLUSH_NONE) {
+ falcon_flush_rx_queue(rx_queue);
+ ++rx_pending;
+ }
+ }
+ efx_for_each_tx_queue(tx_queue, efx) {
+ if (tx_queue->flushed != FLUSH_DONE)
+ ++tx_pending;
+ }
- /* Check if every queue has been succesfully flushed */
- outstanding = false;
- efx_for_each_tx_queue(tx_queue, efx)
- outstanding |= !tx_queue->flushed;
- efx_for_each_rx_queue(rx_queue, efx)
- outstanding |= !rx_queue->flushed;
- if (!outstanding)
+ if (rx_pending == 0 && tx_pending == 0)
return 0;
+
+ msleep(FALCON_FLUSH_INTERVAL);
+ falcon_poll_flush_events(efx);
}
/* Mark the queues as all flushed. We're going to return failure
- * leading to a reset, or fake up success anyway. "flushed" now
- * indicates that we tried to flush. */
+ * leading to a reset, or fake up success anyway */
efx_for_each_tx_queue(tx_queue, efx) {
- if (!tx_queue->flushed)
+ if (tx_queue->flushed != FLUSH_DONE)
EFX_ERR(efx, "tx queue %d flush command timed out\n",
tx_queue->queue);
- tx_queue->flushed = true;
+ tx_queue->flushed = FLUSH_DONE;
}
efx_for_each_rx_queue(rx_queue, efx) {
- if (!rx_queue->flushed)
+ if (rx_queue->flushed != FLUSH_DONE)
EFX_ERR(efx, "rx queue %d flush command timed out\n",
rx_queue->queue);
- rx_queue->flushed = true;
+ rx_queue->flushed = FLUSH_DONE;
}
if (EFX_WORKAROUND_7803(efx))
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index ac808d5..d0755ab 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -113,6 +113,13 @@ struct efx_special_buffer {
int entries;
};
+enum efx_flush_state {
+ FLUSH_NONE,
+ FLUSH_PENDING,
+ FLUSH_FAILED,
+ FLUSH_DONE,
+};
+
/**
* struct efx_tx_buffer - An Efx TX buffer
* @skb: The associated socket buffer.
@@ -189,7 +196,7 @@ struct efx_tx_queue {
struct efx_nic *nic;
struct efx_tx_buffer *buffer;
struct efx_special_buffer txd;
- bool flushed;
+ enum efx_flush_state flushed;
/* Members used mainly on the completion path */
unsigned int read_count ____cacheline_aligned_in_smp;
@@ -284,7 +291,7 @@ struct efx_rx_queue {
struct page *buf_page;
dma_addr_t buf_dma_addr;
char *buf_data;
- bool flushed;
+ enum efx_flush_state flushed;
};
/**
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
--
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