Date: Thu, 14 Jun 2018 16:51:39 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r335150 - stable/11/sys/dev/nvme Message-ID: <201806141651.w5EGpdWU079326@repo.freebsd.org>
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Author: mav Date: Thu Jun 14 16:51:39 2018 New Revision: 335150 URL: https://svnweb.freebsd.org/changeset/base/335150 Log: MFC r331046 (by imp): Try polling the qpairs on timeout. On some systems, we're getting timeouts when we use multiple queues on drives that work perfectly well on other systems. On a hunch, Jim Harris suggested I poll the completion queue when we get a timeout. This patch polls the completion queue if no fatal status was indicated. If it had pending I/O, we complete that request and return. Otherwise, if aborts are enabled and no fatal status, we abort the command and return. Otherwise we reset the card. This may clear up the problem, or we may see it result in lots of timeouts and a performance problem. Either way, we'll know the next step. We may also need to pay attention to the fatal status bit of the controller. Modified: stable/11/sys/dev/nvme/nvme_private.h stable/11/sys/dev/nvme/nvme_qpair.c Modified: stable/11/sys/dev/nvme/nvme_private.h ============================================================================== --- stable/11/sys/dev/nvme/nvme_private.h Thu Jun 14 16:19:05 2018 (r335149) +++ stable/11/sys/dev/nvme/nvme_private.h Thu Jun 14 16:51:39 2018 (r335150) @@ -424,7 +424,7 @@ int nvme_qpair_construct(struct nvme_qpair *qpair, uin struct nvme_controller *ctrlr); void nvme_qpair_submit_tracker(struct nvme_qpair *qpair, struct nvme_tracker *tr); -void nvme_qpair_process_completions(struct nvme_qpair *qpair); +bool nvme_qpair_process_completions(struct nvme_qpair *qpair); void nvme_qpair_submit_request(struct nvme_qpair *qpair, struct nvme_request *req); void nvme_qpair_reset(struct nvme_qpair *qpair); Modified: stable/11/sys/dev/nvme/nvme_qpair.c ============================================================================== --- stable/11/sys/dev/nvme/nvme_qpair.c Thu Jun 14 16:19:05 2018 (r335149) +++ stable/11/sys/dev/nvme/nvme_qpair.c Thu Jun 14 16:51:39 2018 (r335150) @@ -389,11 +389,12 @@ nvme_qpair_manual_complete_request(struct nvme_qpair * nvme_free_request(req); } -void +bool nvme_qpair_process_completions(struct nvme_qpair *qpair) { struct nvme_tracker *tr; struct nvme_completion *cpl; + int done = 0; qpair->num_intr_handler_calls++; @@ -404,7 +405,7 @@ nvme_qpair_process_completions(struct nvme_qpair *qpai * associated with this interrupt will get retried when the * reset is complete. */ - return; + return (false); while (1) { cpl = &qpair->cpl[qpair->cq_head]; @@ -417,6 +418,7 @@ nvme_qpair_process_completions(struct nvme_qpair *qpai if (tr != NULL) { nvme_qpair_complete_tracker(qpair, tr, cpl, TRUE); qpair->sq_head = cpl->sqhd; + done++; } else { nvme_printf(qpair->ctrlr, "cpl does not map to outstanding cmd\n"); @@ -432,6 +434,7 @@ nvme_qpair_process_completions(struct nvme_qpair *qpai nvme_mmio_write_4(qpair->ctrlr, doorbell[qpair->id].cq_hdbl, qpair->cq_head); } + return (done != 0); } static void @@ -685,18 +688,29 @@ nvme_timeout(void *arg) struct nvme_controller *ctrlr = qpair->ctrlr; union csts_register csts; - /* Read csts to get value of cfs - controller fatal status. */ + /* + * Read csts to get value of cfs - controller fatal status. + * If no fatal status, try to call the completion routine, and + * if completes transactions, report a missed interrupt and + * return (this may need to be rate limited). Otherwise, if + * aborts are enabled and the controller is not reporting + * fatal status, abort the command. Otherwise, just reset the + * controller and hope for the best. + */ csts.raw = nvme_mmio_read_4(ctrlr, csts); - + if (csts.bits.cfs == 0 && nvme_qpair_process_completions(qpair)) { + nvme_printf(ctrlr, "Missing interrupt\n"); + return; + } if (ctrlr->enable_aborts && csts.bits.cfs == 0) { - /* - * If aborts are enabled, only use them if the controller is - * not reporting fatal status. - */ + nvme_printf(ctrlr, "Aborting command due to a timeout.\n"); nvme_ctrlr_cmd_abort(ctrlr, tr->cid, qpair->id, nvme_abort_complete, tr); - } else + } else { + nvme_printf(ctrlr, "Resetting controller due to a timeout%s.\n", + csts.bits.cfs ? " and fatal error status" : ""); nvme_ctrlr_reset(ctrlr); + } } void
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