Attachment 140044 Details for Bug 106832 – fix patch by bisect

fix patch by bisect

fix-patch-0001-drm-i915-execlists-Unwind-incomplete-requests-on-res.patch (text/plain), 5.08 KB, created by Owen Zhang on 2018-06-06 05:43:31 UTC

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Creator: Owen Zhang

Created: 2018-06-06 05:43:31 UTC

Size: 5.08 KB

patch

obsolete

>From 221ab9719bf33ad2984928d2afb20988d652a289 Mon Sep 17 00:00:00 2001
>From: Chris Wilson <chris@chris-wilson.co.uk>
>Date: Sat, 16 Sep 2017 21:44:14 +0100
>Subject: [PATCH] drm/i915/execlists: Unwind incomplete requests on resets
>MIME-Version: 1.0
>Content-Type: text/plain; charset=UTF-8
>Content-Transfer-Encoding: 8bit
>
>Given the mechanism to unwind and replay requests (designed to support
>preemption), we have an alternative to the current method of
>resubmitting the ELSP upon reset. Resubmitting ELSP turns out to be more
>complicated than expected, due to having to handle lost context-switch
>interrupts and so guessing what ELSP we need to resubmit later. Instead,
>by unwinding the requests and clearing the ELSP tracking entirely, we
>can then just dequeue the first pair of ready requests after resetting,
>using the normal submission procedure.
>
>Currently, the unwound requests have maximum priority and so are
>guaranteed to be resubmitted upon resume. If we are lucky, we may be
>able to coalesce a new request on top!
>
>Suggested-by: MichaÅ Winiarski <michal.winiarski@intel.com>
>Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>Cc: MichaÅ Winiarski <michal.winiarski@intel.com>
>Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
>Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>Link: https://patchwork.freedesktop.org/patch/msgid/20170916204414.32762-4-chris@chris-wilson.co.uk
>Reviewed-by: MichaÅ Winiarski <michal.winiarski@intel.com>
>---
> drivers/gpu/drm/i915/intel_lrc.c | 61 +++++++++++++++++-----------------------
> 1 file changed, 26 insertions(+), 35 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
>index be2cba6..94a89ef 100644
>--- a/drivers/gpu/drm/i915/intel_lrc.c
>+++ b/drivers/gpu/drm/i915/intel_lrc.c
>@@ -1308,9 +1308,6 @@ static int intel_init_workaround_bb(struct intel_engine_cs *engine)
> static int gen8_init_common_ring(struct intel_engine_cs *engine)
> {
> 	struct drm_i915_private *dev_priv = engine->i915;
>-	struct execlist_port *port = engine->execlist_port;
>-	unsigned int n;
>-	bool submit;
> 	int ret;
> 
> 	ret = intel_mocs_init_engine(engine);
>@@ -1346,26 +1343,8 @@ static int gen8_init_common_ring(struct intel_engine_cs *engine)
> 	engine->csb_head = -1;
> 
> 	/* After a GPU reset, we may have requests to replay */
>-	submit = false;
>-	for (n = 0; n < ARRAY_SIZE(engine->execlist_port); n++) {
>-		if (!port_isset(&port[n]))
>-			break;
>-
>-		DRM_DEBUG_DRIVER("Restarting %s:%d from 0x%x\n",
>-				 engine->name, n,
>-				 port_request(&port[n])->global_seqno);
>-
>-		/* Discard the current inflight count */
>-		port_set(&port[n], port_request(&port[n]));
>-		submit = true;
>-	}
>-
>-	if (!i915.enable_guc_submission) {
>-		if (submit)
>-			execlists_submit_ports(engine);
>-		else if (engine->execlist_first)
>-			tasklet_schedule(&engine->irq_tasklet);
>-	}
>+	if (!i915.enable_guc_submission && engine->execlist_first)
>+		tasklet_schedule(&engine->irq_tasklet);
> 
> 	return 0;
> }
>@@ -1407,9 +1386,13 @@ static void reset_common_ring(struct intel_engine_cs *engine,
> 			      struct drm_i915_gem_request *request)
> {
> 	struct execlist_port *port = engine->execlist_port;
>+	struct drm_i915_gem_request *rq, *rn;
> 	struct intel_context *ce;
>+	unsigned long flags;
> 	unsigned int n;
> 
>+	spin_lock_irqsave(&engine->timeline->lock, flags);
>+
> 	/*
> 	 * Catch up with any missed context-switch interrupts.
> 	 *
>@@ -1419,20 +1402,28 @@ static void reset_common_ring(struct intel_engine_cs *engine,
> 	 * guessing the missed context-switch events by looking at what
> 	 * requests were completed.
> 	 */
>-	if (!request) {
>-		for (n = 0; n < ARRAY_SIZE(engine->execlist_port); n++)
>-			i915_gem_request_put(port_request(&port[n]));
>-		memset(engine->execlist_port, 0, sizeof(engine->execlist_port));
>-		return;
>-	}
>+	for (n = 0; n < ARRAY_SIZE(engine->execlist_port); n++)
>+		i915_gem_request_put(port_request(&port[n]));
>+	memset(engine->execlist_port, 0, sizeof(engine->execlist_port));
> 
>-	if (request->ctx != port_request(port)->ctx) {
>-		i915_gem_request_put(port_request(port));
>-		port[0] = port[1];
>-		memset(&port[1], 0, sizeof(port[1]));
>+	/* Push back any incomplete requests for replay after the reset. */
>+	list_for_each_entry_safe_reverse(rq, rn,
>+					 &engine->timeline->requests, link) {
>+		struct i915_priolist *p;
>+
>+		if (i915_gem_request_completed(rq))
>+			break;
>+
>+		__i915_gem_request_unsubmit(rq);
>+
>+		p = lookup_priolist(engine,
>+				    &rq->priotree,
>+				    rq->priotree.priority);
>+		list_add(&rq->priotree.link,
>+			 &ptr_mask_bits(p, 1)->requests);
> 	}
> 
>-	GEM_BUG_ON(request->ctx != port_request(port)->ctx);
>+	spin_unlock_irqrestore(&engine->timeline->lock, flags);
> 
> 	/* If the request was innocent, we leave the request in the ELSP
> 	 * and will try to replay it on restarting. The context image may
>@@ -1444,7 +1435,7 @@ static void reset_common_ring(struct intel_engine_cs *engine,
> 	 * and have to at least restore the RING register in the context
> 	 * image back to the expected values to skip over the guilty request.
> 	 */
>-	if (request->fence.error != -EIO)
>+	if (!request || request->fence.error != -EIO)
> 		return;
> 
> 	/* We want a simple context + ring to execute the breadcrumb update.
>-- 
>1.8.3.1
>

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