[PATCH v9 01/21] drm/i915: Look for active requests earlier in the reset path

Michel Thierry
2017-06-15T20:18:30Z

And store the active request so that we only search for it once.

v2: Check for request completion inside _prepare_engine, don't use
ECANCELED, remove unnecessary null checks (Chris).

v3: Capture active requests during reset_prepare and store it the
engine hangcheck obj.

v4: Rename commit, change i915_gem_reset_request to just confirm the
active_request is still incomplete, instead of engine_stalled (Chris).

v5: With style; pass the active request to gem_reset_engine, keep single
return in reset_prepare_engine (Chris).

v6: Moved before reset-engine code appears (Chris)

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v5)
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
---
drivers/gpu/drm/i915/i915_gem.c | 14 +++++++-------
drivers/gpu/drm/i915/intel_ringbuffer.h | 1 +
2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 31cbe78171a9..4722cd3567a5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2820,7 +2820,7 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv)

/* Ensure irq handler finishes, and not run again. */
for_each_engine(engine, dev_priv, id) {
- struct drm_i915_gem_request *request;
+ struct drm_i915_gem_request *request = NULL;

/* Prevent the signaler thread from updating the request
* state (by calling dma_fence_signal) as we are processing
@@ -2852,6 +2852,8 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv)
if (request && request->fence.error == -EIO)
err = -EIO; /* Previous reset failed! */
}
+
+ engine->hangcheck.active_request = request;
}

i915_gem_revoke_fences(dev_priv);
@@ -2905,7 +2907,7 @@ static void engine_skip_context(struct drm_i915_gem_request *request)
static bool i915_gem_reset_request(struct drm_i915_gem_request *request)
{
/* Read once and return the resolution */
- const bool guilty = engine_stalled(request->engine);
+ const bool guilty = !i915_gem_request_completed(request);

/* The guilty request will get skipped on a hung engine.
*
@@ -2939,11 +2941,9 @@ static bool i915_gem_reset_request(struct drm_i915_gem_request *request)
return guilty;
}

-static void i915_gem_reset_engine(struct intel_engine_cs *engine)
+static void i915_gem_reset_engine(struct intel_engine_cs *engine,
+ struct drm_i915_gem_request *request)
{
- struct drm_i915_gem_request *request;
-
- request = i915_gem_find_active_request(engine);
if (request && i915_gem_reset_request(request)) {
DRM_DEBUG_DRIVER("resetting %s to restart from tail of request 0x%x\n",
engine->name, request->global_seqno);
@@ -2969,7 +2969,7 @@ void i915_gem_reset(struct drm_i915_private *dev_priv)
for_each_engine(engine, dev_priv, id) {
struct i915_gem_context *ctx;

- i915_gem_reset_engine(engine);
+ i915_gem_reset_engine(engine, engine->hangcheck.active_request);
ctx = fetch_and_zero(&engine->last_retired_context);
if (ctx)
engine->context_unpin(engine, ctx);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 6aa20ac8cde3..d33c93444c0d 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -121,6 +121,7 @@ struct intel_engine_hangcheck {
unsigned long action_timestamp;
int deadlock;
struct intel_instdone instdone;
+ struct drm_i915_gem_request *active_request;
bool stalled;
};