From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 10/11] i40e/i40evf: Ignore a driver perceived Tx hang if the number of desc pending < 4 Date: Wed, 27 Aug 2014 02:26:45 -0700 Message-ID: <1409131606-15011-11-git-send-email-jeffrey.t.kirsher@intel.com> References: <1409131606-15011-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Anjali Singhai Jain , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga01.intel.com ([192.55.52.88]:64393 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932981AbaH0J0z (ORCPT ); Wed, 27 Aug 2014 05:26:55 -0400 In-Reply-To: <1409131606-15011-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Anjali Singhai Jain We are seeing situations where the driver sees a hang with less than 4 desc pending, if the driver chooses to ignore it the queue progresses forward and the stack never experiences a real hang. With this patch we will log a stat when this situation happens "tx_sluggish" will increment and we can see some more details at a higher debug level. Other than that we will ignore this particular case of Tx hang. Change-ID: I7d1d1666d990e2b12f4f6bed0d17d22e1b6410d5 Signed-off-by: Anjali Singhai Jain Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40e/i40e.h | 1 + drivers/net/ethernet/intel/i40e/i40e_debugfs.c | 3 +++ drivers/net/ethernet/intel/i40e/i40e_txrx.c | 10 +++++++++- drivers/net/ethernet/intel/i40e/i40e_txrx.h | 1 + drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 6 ++++-- drivers/net/ethernet/intel/i40evf/i40e_txrx.h | 1 + 6 files changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h index 8526950..4e97ba1 100644 --- a/drivers/net/ethernet/intel/i40e/i40e.h +++ b/drivers/net/ethernet/intel/i40e/i40e.h @@ -316,6 +316,7 @@ struct i40e_pf { u32 tx_timeout_count; u32 tx_timeout_recovery_level; unsigned long tx_timeout_last_recovery; + u32 tx_sluggish_count; u32 hw_csum_rx_error; u32 led_status; u16 corer_count; /* Core reset count */ diff --git a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c index 5a0cabe..7067f4b 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c +++ b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c @@ -1356,6 +1356,9 @@ static ssize_t i40e_dbg_command_write(struct file *filp, "emp reset count: %d\n", pf->empr_count); dev_info(&pf->pdev->dev, "pf reset count: %d\n", pf->pfr_count); + dev_info(&pf->pdev->dev, + "pf tx sluggish count: %d\n", + pf->tx_sluggish_count); } else if (strncmp(&cmd_buf[5], "port", 4) == 0) { struct i40e_aqc_query_port_ets_config_resp *bw_data; struct i40e_dcbx_config *cfg = diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 366624a..4bf49d2 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -607,6 +607,7 @@ static u32 i40e_get_tx_pending(struct i40e_ring *ring) static bool i40e_check_tx_hang(struct i40e_ring *tx_ring) { u32 tx_pending = i40e_get_tx_pending(tx_ring); + struct i40e_pf *pf = tx_ring->vsi->back; bool ret = false; clear_check_for_tx_hang(tx_ring); @@ -623,10 +624,17 @@ static bool i40e_check_tx_hang(struct i40e_ring *tx_ring) * pending but without time to complete it yet. */ if ((tx_ring->tx_stats.tx_done_old == tx_ring->stats.packets) && - tx_pending) { + (tx_pending >= I40E_MIN_DESC_PENDING)) { /* make sure it is true for two checks in a row */ ret = test_and_set_bit(__I40E_HANG_CHECK_ARMED, &tx_ring->state); + } else if ((tx_ring->tx_stats.tx_done_old == tx_ring->stats.packets) && + (tx_pending < I40E_MIN_DESC_PENDING) && + (tx_pending > 0)) { + if (I40E_DEBUG_FLOW & pf->hw.debug_mask) + dev_info(tx_ring->dev, "HW needs some more descs to do a cacheline flush. tx_pending %d, queue %d", + tx_pending, tx_ring->queue_index); + pf->tx_sluggish_count++; } else { /* update completed stats and disarm the hang check */ tx_ring->tx_stats.tx_done_old = tx_ring->stats.packets; diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h index 73f4fa4..d7a625a 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h @@ -121,6 +121,7 @@ enum i40e_dyn_idx_t { /* Tx Descriptors needed, worst case */ #define TXD_USE_COUNT(S) DIV_ROUND_UP((S), I40E_MAX_DATA_PER_TXD) #define DESC_NEEDED (MAX_SKB_FRAGS + 4) +#define I40E_MIN_DESC_PENDING 4 #define I40E_TX_FLAGS_CSUM (u32)(1) #define I40E_TX_FLAGS_HW_VLAN (u32)(1 << 1) diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 79bf96c..64b0891 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -163,11 +163,13 @@ static bool i40e_check_tx_hang(struct i40e_ring *tx_ring) * pending but without time to complete it yet. */ if ((tx_ring->tx_stats.tx_done_old == tx_ring->stats.packets) && - tx_pending) { + (tx_pending >= I40E_MIN_DESC_PENDING)) { /* make sure it is true for two checks in a row */ ret = test_and_set_bit(__I40E_HANG_CHECK_ARMED, &tx_ring->state); - } else { + } else if (!(tx_ring->tx_stats.tx_done_old == tx_ring->stats.packets) || + !(tx_pending < I40E_MIN_DESC_PENDING) || + !(tx_pending > 0)) { /* update completed stats and disarm the hang check */ tx_ring->tx_stats.tx_done_old = tx_ring->stats.packets; clear_bit(__I40E_HANG_CHECK_ARMED, &tx_ring->state); diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h index 8bc6858..f6dcf9d 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h @@ -121,6 +121,7 @@ enum i40e_dyn_idx_t { /* Tx Descriptors needed, worst case */ #define TXD_USE_COUNT(S) DIV_ROUND_UP((S), I40E_MAX_DATA_PER_TXD) #define DESC_NEEDED (MAX_SKB_FRAGS + 4) +#define I40E_MIN_DESC_PENDING 4 #define I40E_TX_FLAGS_CSUM (u32)(1) #define I40E_TX_FLAGS_HW_VLAN (u32)(1 << 1) -- 1.9.3