From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alice Michael Date: Wed, 5 Apr 2017 07:50:56 -0400 Subject: [Intel-wired-lan] [next S66 v2 04/11] i40e: Simplify i40e_detect_recover_hung_queue logic In-Reply-To: <20170405115103.67374-1-alice.michael@intel.com> References: <20170405115103.67374-1-alice.michael@intel.com> Message-ID: <20170405115103.67374-4-alice.michael@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: From: Alan Brady This patch greatly reduces the unneeded complexity in the i40e_detect_recover_hung_queue code path. The previous implementation set a 'hung bit' which would then get cleared while polling. If the detection routine was called a second time with the bit already set, we would issue a software interrupt. This patch makes it such that if interrupts are disabled and we have pending TX descriptors, we trigger a software interrupt since in, the worst case, queues are already clean and we have an extra interrupt. Additionally this patch removes the workaround for lost interrupts as calling napi_reschedule in this context can cause software interrupts to fire on the wrong CPU. Signed-off-by: Alan Brady Change-ID: Iae108582a3ceb6229ed1d22e4ed6e69cf97aad8d --- drivers/net/ethernet/intel/i40e/i40e.h | 4 -- drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 1 - drivers/net/ethernet/intel/i40e/i40e_main.c | 59 +++++--------------------- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 12 ++---- drivers/net/ethernet/intel/i40e/i40e_txrx.h | 3 +- 5 files changed, 15 insertions(+), 64 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h index 2c12900..e987503 100644 --- a/drivers/net/ethernet/intel/i40e/i40e.h +++ b/drivers/net/ethernet/intel/i40e/i40e.h @@ -613,7 +613,6 @@ struct i40e_vsi { u32 tx_busy; u64 tx_linearize; u64 tx_force_wb; - u64 tx_lost_interrupt; u32 rx_buf_failed; u32 rx_page_failed; @@ -699,9 +698,6 @@ struct i40e_q_vector { u8 num_ringpairs; /* total number of ring pairs in vector */ -#define I40E_Q_VECTOR_HUNG_DETECT 0 /* Bit Index for hung detection logic */ - unsigned long hung_detected; /* Set/Reset for hung_detection logic */ - cpumask_t affinity_mask; struct irq_affinity_notify affinity_notify; diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c index 68c0f20..10325b5 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c +++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c @@ -89,7 +89,6 @@ static const struct i40e_stats i40e_gstrings_misc_stats[] = { I40E_VSI_STAT("rx_unknown_protocol", eth_stats.rx_unknown_protocol), I40E_VSI_STAT("tx_linearize", tx_linearize), I40E_VSI_STAT("tx_force_wb", tx_force_wb), - I40E_VSI_STAT("tx_lost_interrupt", tx_lost_interrupt), I40E_VSI_STAT("rx_alloc_fail", rx_buf_failed), I40E_VSI_STAT("rx_pg_alloc_fail", rx_page_failed), }; diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 33725a5..fcfab36 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -737,7 +737,6 @@ static void i40e_update_vsi_stats(struct i40e_vsi *vsi) struct i40e_eth_stats *oes; struct i40e_eth_stats *es; /* device's eth stats */ u32 tx_restart, tx_busy; - u64 tx_lost_interrupt; struct i40e_ring *p; u32 rx_page, rx_buf; u64 bytes, packets; @@ -763,7 +762,6 @@ static void i40e_update_vsi_stats(struct i40e_vsi *vsi) rx_b = rx_p = 0; tx_b = tx_p = 0; tx_restart = tx_busy = tx_linearize = tx_force_wb = 0; - tx_lost_interrupt = 0; rx_page = 0; rx_buf = 0; rcu_read_lock(); @@ -782,7 +780,6 @@ static void i40e_update_vsi_stats(struct i40e_vsi *vsi) tx_busy += p->tx_stats.tx_busy; tx_linearize += p->tx_stats.tx_linearize; tx_force_wb += p->tx_stats.tx_force_wb; - tx_lost_interrupt += p->tx_stats.tx_lost_interrupt; /* Rx queue is part of the same block as Tx queue */ p = &p[1]; @@ -801,7 +798,6 @@ static void i40e_update_vsi_stats(struct i40e_vsi *vsi) vsi->tx_busy = tx_busy; vsi->tx_linearize = tx_linearize; vsi->tx_force_wb = tx_force_wb; - vsi->tx_lost_interrupt = tx_lost_interrupt; vsi->rx_page_failed = rx_page; vsi->rx_buf_failed = rx_buf; @@ -4499,16 +4495,15 @@ static int i40e_pf_wait_queues_disabled(struct i40e_pf *pf) * @vsi: Pointer to VSI struct * * This function checks specified queue for given VSI. Detects hung condition. - * Sets hung bit since it is two step process. Before next run of service task - * if napi_poll runs, it reset 'hung' bit for respective q_vector. If not, - * hung condition remain unchanged and during subsequent run, this function - * issues SW interrupt to recover from hung condition. + * We proactively detect hung TX queues by checking if interrupts are disabled + * but there are pending descriptors. If it appears hung, attempt to recover + * by triggering a SW interrupt. **/ static void i40e_detect_recover_hung_queue(int q_idx, struct i40e_vsi *vsi) { struct i40e_ring *tx_ring = NULL; struct i40e_pf *pf; - u32 head, val, tx_pending_hw; + u32 val, tx_pending; int i; pf = vsi->back; @@ -4534,47 +4529,15 @@ static void i40e_detect_recover_hung_queue(int q_idx, struct i40e_vsi *vsi) else val = rd32(&pf->hw, I40E_PFINT_DYN_CTL0); - head = i40e_get_head(tx_ring); + tx_pending = i40e_get_tx_pending(tx_ring); - tx_pending_hw = i40e_get_tx_pending(tx_ring, false); - - /* HW is done executing descriptors, updated HEAD write back, - * but SW hasn't processed those descriptors. If interrupt is - * not generated from this point ON, it could result into - * dev_watchdog detecting timeout on those netdev_queue, - * hence proactively trigger SW interrupt. + /* Interrupts are disabled and TX pending is non-zero, + * trigger the SW interrupt (don't wait). Worst case + * there will be one extra interrupt which may result + * into not cleaning any queues because queues are cleaned. */ - if (tx_pending_hw && (!(val & I40E_PFINT_DYN_CTLN_INTENA_MASK))) { - /* NAPI Poll didn't run and clear since it was set */ - if (test_and_clear_bit(I40E_Q_VECTOR_HUNG_DETECT, - &tx_ring->q_vector->hung_detected)) { - netdev_info(vsi->netdev, "VSI_seid %d, Hung TX queue %d, tx_pending_hw: %d, NTC:0x%x, HWB: 0x%x, NTU: 0x%x, TAIL: 0x%x\n", - vsi->seid, q_idx, tx_pending_hw, - tx_ring->next_to_clean, head, - tx_ring->next_to_use, - readl(tx_ring->tail)); - netdev_info(vsi->netdev, "VSI_seid %d, Issuing force_wb for TX queue %d, Interrupt Reg: 0x%x\n", - vsi->seid, q_idx, val); - i40e_force_wb(vsi, tx_ring->q_vector); - } else { - /* First Chance - detected possible hung */ - set_bit(I40E_Q_VECTOR_HUNG_DETECT, - &tx_ring->q_vector->hung_detected); - } - } - - /* This is the case where we have interrupts missing, - * so the tx_pending in HW will most likely be 0, but we - * will have tx_pending in SW since the WB happened but the - * interrupt got lost. - */ - if ((!tx_pending_hw) && i40e_get_tx_pending(tx_ring, true) && - (!(val & I40E_PFINT_DYN_CTLN_INTENA_MASK))) { - local_bh_disable(); - if (napi_reschedule(&tx_ring->q_vector->napi)) - tx_ring->tx_stats.tx_lost_interrupt++; - local_bh_enable(); - } + if (tx_pending && (!(val & I40E_PFINT_DYN_CTLN_INTENA_MASK))) + i40e_force_wb(vsi, tx_ring->q_vector); } /** diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 9b92d00..b4a7bfc 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -711,19 +711,15 @@ void i40e_free_tx_resources(struct i40e_ring *tx_ring) /** * i40e_get_tx_pending - how many tx descriptors not processed * @tx_ring: the ring of descriptors - * @in_sw: is tx_pending being checked in SW or HW * * Since there is no access to the ring head register * in XL710, we need to use our local copies **/ -u32 i40e_get_tx_pending(struct i40e_ring *ring, bool in_sw) +u32 i40e_get_tx_pending(struct i40e_ring *ring) { u32 head, tail; - if (!in_sw) - head = i40e_get_head(ring); - else - head = ring->next_to_clean; + head = i40e_get_head(ring); tail = readl(ring->tail); if (head != tail) @@ -846,7 +842,7 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi, * them to be written back in case we stay in NAPI. * In this mode on X722 we do not enable Interrupt. */ - unsigned int j = i40e_get_tx_pending(tx_ring, false); + unsigned int j = i40e_get_tx_pending(tx_ring); if (budget && ((j / WB_STRIDE) == 0) && (j > 0) && @@ -2185,8 +2181,6 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) return 0; } - /* Clear hung_detected bit */ - clear_bit(I40E_Q_VECTOR_HUNG_DETECT, &q_vector->hung_detected); /* Since the actual Tx work is minimal, we can give the Tx a larger * budget and be more aggressive about cleaning up the Tx descriptors. */ diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h index 2e876ad..f5de511 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h @@ -328,7 +328,6 @@ struct i40e_tx_queue_stats { u64 tx_done_old; u64 tx_linearize; u64 tx_force_wb; - u64 tx_lost_interrupt; }; struct i40e_rx_queue_stats { @@ -480,7 +479,7 @@ void i40e_free_tx_resources(struct i40e_ring *tx_ring); void i40e_free_rx_resources(struct i40e_ring *rx_ring); int i40e_napi_poll(struct napi_struct *napi, int budget); void i40e_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector); -u32 i40e_get_tx_pending(struct i40e_ring *ring, bool in_sw); +u32 i40e_get_tx_pending(struct i40e_ring *ring); int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size); bool __i40e_chk_linearize(struct sk_buff *skb); -- 2.9.3