From 0f4d201f74f0d4f1f88c367185591195c8151e9c Mon Sep 17 00:00:00 2001 From: Kumar Sanghvi Date: Thu, 13 Mar 2014 20:50:48 +0530 Subject: cxgb4: Rectify emitting messages about SGE Ingress DMA channels being potentially stuck Based on original work by Casey Leedom Signed-off-by: Kumar Sanghvi Signed-off-by: David S. Miller --- drivers/net/ethernet/chelsio/cxgb4/cxgb4.h | 9 ++- drivers/net/ethernet/chelsio/cxgb4/sge.c | 90 ++++++++++++++++++++++++------ 2 files changed, 79 insertions(+), 20 deletions(-) (limited to 'drivers') diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h b/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h index 509c97610343..50abe1d61287 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h @@ -556,8 +556,13 @@ struct sge { u32 pktshift; /* padding between CPL & packet data */ u32 fl_align; /* response queue message alignment */ u32 fl_starve_thres; /* Free List starvation threshold */ - unsigned int starve_thres; - u8 idma_state[2]; + + /* State variables for detecting an SGE Ingress DMA hang */ + unsigned int idma_1s_thresh;/* SGE same State Counter 1s threshold */ + unsigned int idma_stalled[2];/* SGE synthesized stalled timers in HZ */ + unsigned int idma_state[2]; /* SGE IDMA Hang detect state */ + unsigned int idma_qid[2]; /* SGE IDMA Hung Ingress Queue ID */ + unsigned int egr_start; unsigned int ingr_start; void *egr_map[MAX_EGRQ]; /* qid->queue egress queue map */ diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c index 3a2ecd84afee..054bb0389c09 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/sge.c +++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c @@ -93,6 +93,16 @@ */ #define TX_QCHECK_PERIOD (HZ / 2) +/* SGE Hung Ingress DMA Threshold Warning time (in Hz) and Warning Repeat Rate + * (in RX_QCHECK_PERIOD multiples). If we find one of the SGE Ingress DMA + * State Machines in the same state for this amount of time (in HZ) then we'll + * issue a warning about a potential hang. We'll repeat the warning as the + * SGE Ingress DMA Channel appears to be hung every N RX_QCHECK_PERIODs till + * the situation clears. If the situation clears, we'll note that as well. + */ +#define SGE_IDMA_WARN_THRESH (1 * HZ) +#define SGE_IDMA_WARN_REPEAT (20 * RX_QCHECK_PERIOD) + /* * Max number of Tx descriptors to be reclaimed by the Tx timer. */ @@ -2008,7 +2018,7 @@ irq_handler_t t4_intr_handler(struct adapter *adap) static void sge_rx_timer_cb(unsigned long data) { unsigned long m; - unsigned int i, cnt[2]; + unsigned int i, idma_same_state_cnt[2]; struct adapter *adap = (struct adapter *)data; struct sge *s = &adap->sge; @@ -2031,21 +2041,64 @@ static void sge_rx_timer_cb(unsigned long data) } t4_write_reg(adap, SGE_DEBUG_INDEX, 13); - cnt[0] = t4_read_reg(adap, SGE_DEBUG_DATA_HIGH); - cnt[1] = t4_read_reg(adap, SGE_DEBUG_DATA_LOW); - - for (i = 0; i < 2; i++) - if (cnt[i] >= s->starve_thres) { - if (s->idma_state[i] || cnt[i] == 0xffffffff) - continue; - s->idma_state[i] = 1; - t4_write_reg(adap, SGE_DEBUG_INDEX, 11); - m = t4_read_reg(adap, SGE_DEBUG_DATA_LOW) >> (i * 16); - dev_warn(adap->pdev_dev, - "SGE idma%u starvation detected for " - "queue %lu\n", i, m & 0xffff); - } else if (s->idma_state[i]) - s->idma_state[i] = 0; + idma_same_state_cnt[0] = t4_read_reg(adap, SGE_DEBUG_DATA_HIGH); + idma_same_state_cnt[1] = t4_read_reg(adap, SGE_DEBUG_DATA_LOW); + + for (i = 0; i < 2; i++) { + u32 debug0, debug11; + + /* If the Ingress DMA Same State Counter ("timer") is less + * than 1s, then we can reset our synthesized Stall Timer and + * continue. If we have previously emitted warnings about a + * potential stalled Ingress Queue, issue a note indicating + * that the Ingress Queue has resumed forward progress. + */ + if (idma_same_state_cnt[i] < s->idma_1s_thresh) { + if (s->idma_stalled[i] >= SGE_IDMA_WARN_THRESH) + CH_WARN(adap, "SGE idma%d, queue%u,resumed after %d sec\n", + i, s->idma_qid[i], + s->idma_stalled[i]/HZ); + s->idma_stalled[i] = 0; + continue; + } + + /* Synthesize an SGE Ingress DMA Same State Timer in the Hz + * domain. The first time we get here it'll be because we + * passed the 1s Threshold; each additional time it'll be + * because the RX Timer Callback is being fired on its regular + * schedule. + * + * If the stall is below our Potential Hung Ingress Queue + * Warning Threshold, continue. + */ + if (s->idma_stalled[i] == 0) + s->idma_stalled[i] = HZ; + else + s->idma_stalled[i] += RX_QCHECK_PERIOD; + + if (s->idma_stalled[i] < SGE_IDMA_WARN_THRESH) + continue; + + /* We'll issue a warning every SGE_IDMA_WARN_REPEAT Hz */ + if (((s->idma_stalled[i] - HZ) % SGE_IDMA_WARN_REPEAT) != 0) + continue; + + /* Read and save the SGE IDMA State and Queue ID information. + * We do this every time in case it changes across time ... + */ + t4_write_reg(adap, SGE_DEBUG_INDEX, 0); + debug0 = t4_read_reg(adap, SGE_DEBUG_DATA_LOW); + s->idma_state[i] = (debug0 >> (i * 9)) & 0x3f; + + t4_write_reg(adap, SGE_DEBUG_INDEX, 11); + debug11 = t4_read_reg(adap, SGE_DEBUG_DATA_LOW); + s->idma_qid[i] = (debug11 >> (i * 16)) & 0xffff; + + CH_WARN(adap, "SGE idma%u, queue%u, maybe stuck state%u %dsecs (debug0=%#x, debug11=%#x)\n", + i, s->idma_qid[i], s->idma_state[i], + s->idma_stalled[i]/HZ, debug0, debug11); + t4_sge_decode_idma_state(adap, s->idma_state[i]); + } mod_timer(&s->rx_timer, jiffies + RX_QCHECK_PERIOD); } @@ -2756,8 +2809,9 @@ int t4_sge_init(struct adapter *adap) setup_timer(&s->rx_timer, sge_rx_timer_cb, (unsigned long)adap); setup_timer(&s->tx_timer, sge_tx_timer_cb, (unsigned long)adap); - s->starve_thres = core_ticks_per_usec(adap) * 1000000; /* 1 s */ - s->idma_state[0] = s->idma_state[1] = 0; + s->idma_1s_thresh = core_ticks_per_usec(adap) * 1000000; /* 1 s */ + s->idma_stalled[0] = 0; + s->idma_stalled[1] = 0; spin_lock_init(&s->intrq_lock); return 0; -- cgit v1.2.3-59-g8ed1b