From patchwork Wed Mar 28 21:18:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10314147 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6476E600F6 for ; Wed, 28 Mar 2018 21:19:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5595329188 for ; Wed, 28 Mar 2018 21:19:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4A2B62990A; Wed, 28 Mar 2018 21:19:29 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6E49129188 for ; Wed, 28 Mar 2018 21:19:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2863A6E260; Wed, 28 Mar 2018 21:19:25 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 02F788982D for ; Wed, 28 Mar 2018 21:19:15 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 11193780-1500050 for multiple; Wed, 28 Mar 2018 22:19:07 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Wed, 28 Mar 2018 22:19:07 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 28 Mar 2018 22:18:46 +0100 Message-Id: <20180328211857.32457-5-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180328211857.32457-1-chris@chris-wilson.co.uk> References: <20180328211857.32457-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH 04/15] drm/i915/execlists: Flush pending preemption events during reset X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP Catch up with the inflight CSB events, after disabling the tasklet before deciding which request was truly guilty of hanging the GPU. v2: Restore checking of use_csb_mmio on every loop, don't forget old vgpu. Signed-off-by: Chris Wilson Cc: Michał Winiarski CC: Michel Thierry Cc: Jeff McGee --- drivers/gpu/drm/i915/intel_lrc.c | 127 +++++++++++++++++++++++++++------------ 1 file changed, 87 insertions(+), 40 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 540e437d9783..89a4c9eb68fa 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -874,34 +874,14 @@ static void execlists_cancel_requests(struct intel_engine_cs *engine) local_irq_restore(flags); } -/* - * Check the unread Context Status Buffers and manage the submission of new - * contexts to the ELSP accordingly. - */ -static void execlists_submission_tasklet(unsigned long data) +static void process_csb(struct intel_engine_cs *engine) { - struct intel_engine_cs * const engine = (struct intel_engine_cs *)data; struct intel_engine_execlists * const execlists = &engine->execlists; struct execlist_port * const port = execlists->port; - struct drm_i915_private *dev_priv = engine->i915; + struct drm_i915_private *i915 = engine->i915; bool fw = false; - /* - * We can skip acquiring intel_runtime_pm_get() here as it was taken - * on our behalf by the request (see i915_gem_mark_busy()) and it will - * not be relinquished until the device is idle (see - * i915_gem_idle_work_handler()). As a precaution, we make sure - * that all ELSP are drained i.e. we have processed the CSB, - * before allowing ourselves to idle and calling intel_runtime_pm_put(). - */ - GEM_BUG_ON(!dev_priv->gt.awake); - - /* - * Prefer doing test_and_clear_bit() as a two stage operation to avoid - * imposing the cost of a locked atomic transaction when submitting a - * new request (outside of the context-switch interrupt). - */ - while (test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)) { + do { /* The HWSP contains a (cacheable) mirror of the CSB */ const u32 *buf = &engine->status_page.page_addr[I915_HWS_CSB_BUF0_INDEX]; @@ -909,28 +889,27 @@ static void execlists_submission_tasklet(unsigned long data) if (unlikely(execlists->csb_use_mmio)) { buf = (u32 * __force) - (dev_priv->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0))); - execlists->csb_head = -1; /* force mmio read of CSB ptrs */ + (i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0))); + execlists->csb_head = -1; /* force mmio read of CSB */ } /* Clear before reading to catch new interrupts */ clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted); smp_mb__after_atomic(); - if (unlikely(execlists->csb_head == -1)) { /* following a reset */ + if (unlikely(execlists->csb_head == -1)) { /* after a reset */ if (!fw) { - intel_uncore_forcewake_get(dev_priv, - execlists->fw_domains); + intel_uncore_forcewake_get(i915, execlists->fw_domains); fw = true; } - head = readl(dev_priv->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine))); + head = readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine))); tail = GEN8_CSB_WRITE_PTR(head); head = GEN8_CSB_READ_PTR(head); execlists->csb_head = head; } else { const int write_idx = - intel_hws_csb_write_index(dev_priv) - + intel_hws_csb_write_index(i915) - I915_HWS_CSB_BUF0_INDEX; head = execlists->csb_head; @@ -938,8 +917,8 @@ static void execlists_submission_tasklet(unsigned long data) } GEM_TRACE("%s cs-irq head=%d [%d%s], tail=%d [%d%s]\n", engine->name, - head, GEN8_CSB_READ_PTR(readl(dev_priv->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?", - tail, GEN8_CSB_WRITE_PTR(readl(dev_priv->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?"); + head, GEN8_CSB_READ_PTR(readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?", + tail, GEN8_CSB_WRITE_PTR(readl(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine)))), fw ? "" : "?"); while (head != tail) { struct i915_request *rq; @@ -949,7 +928,8 @@ static void execlists_submission_tasklet(unsigned long data) if (++head == GEN8_CSB_ENTRIES) head = 0; - /* We are flying near dragons again. + /* + * We are flying near dragons again. * * We hold a reference to the request in execlist_port[] * but no more than that. We are operating in softirq @@ -1040,15 +1020,48 @@ static void execlists_submission_tasklet(unsigned long data) if (head != execlists->csb_head) { execlists->csb_head = head; writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK, head << 8), - dev_priv->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine))); + i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine))); } - } + } while (test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)); - if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_PREEMPT)) - execlists_dequeue(engine); + if (unlikely(fw)) + intel_uncore_forcewake_put(i915, execlists->fw_domains); +} + +/* + * Check the unread Context Status Buffers and manage the submission of new + * contexts to the ELSP accordingly. + */ +static void execlists_submission_tasklet(unsigned long data) +{ + struct intel_engine_cs * const engine = (struct intel_engine_cs *)data; - if (fw) - intel_uncore_forcewake_put(dev_priv, execlists->fw_domains); + GEM_TRACE("%s awake?=%d, active=%x, irq-posted?=%d\n", + engine->name, + engine->i915->gt.awake, + engine->execlists.active, + test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)); + + /* + * We can skip acquiring intel_runtime_pm_get() here as it was taken + * on our behalf by the request (see i915_gem_mark_busy()) and it will + * not be relinquished until the device is idle (see + * i915_gem_idle_work_handler()). As a precaution, we make sure + * that all ELSP are drained i.e. we have processed the CSB, + * before allowing ourselves to idle and calling intel_runtime_pm_put(). + */ + GEM_BUG_ON(!engine->i915->gt.awake); + + /* + * Prefer doing test_and_clear_bit() as a two stage operation to avoid + * imposing the cost of a locked atomic transaction when submitting a + * new request (outside of the context-switch interrupt). + */ + if (test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)) + process_csb(engine); + + if (!execlists_is_active(&engine->execlists, EXECLISTS_ACTIVE_PREEMPT)) + execlists_dequeue(engine); /* If the engine is now idle, so should be the flag; and vice versa. */ GEM_BUG_ON(execlists_is_active(&engine->execlists, @@ -1713,6 +1726,7 @@ static struct i915_request * execlists_reset_prepare(struct intel_engine_cs *engine) { struct intel_engine_execlists * const execlists = &engine->execlists; + struct i915_request *request, *active; GEM_TRACE("%s\n", engine->name); @@ -1736,7 +1750,40 @@ execlists_reset_prepare(struct intel_engine_cs *engine) tasklet_kill(&execlists->tasklet); tasklet_disable(&execlists->tasklet); - return i915_gem_find_active_request(engine); + /* + * We want to flush the pending context switches, having disabled + * the tasklet above, we can assume exclusive access to the execlists. + * For this allows us to catch up with an inflight preemption event, + * and avoid blaming an innocent request if the stall was due to the + * preemption itself. + */ + if (test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)) + process_csb(engine); + + /* + * The last active request can then be no later than the last request + * now in ELSP[0]. So search backwards from there, so that if the GPU + * has advanced beyond the last CSB update, it will be pardoned. + */ + active = NULL; + request = port_request(execlists->port); + if (request) { + unsigned long flags; + + spin_lock_irqsave(&engine->timeline->lock, flags); + list_for_each_entry_from_reverse(request, + &engine->timeline->requests, + link) { + if (__i915_request_completed(request, + request->global_seqno)) + break; + + active = request; + } + spin_unlock_irqrestore(&engine->timeline->lock, flags); + } + + return active; } static void execlists_reset(struct intel_engine_cs *engine,