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| author | Chris Wilson | 2019-02-28 23:06:39 +0100 |
|---|---|---|
| committer | Chris Wilson | 2019-03-01 00:10:43 +0100 |
| commit | b5773a3616d10bdef60662b8780ded912ee5d7b6 (patch) | |
| tree | 4f07f7291f9678e23d4c7e56701978c4be5700c8 /drivers/gpu/drm/i915/i915_request.c | |
| parent | drm/i915: Use __ffs() in for_each_priolist for more compact code (diff) | |
| download | kernel-qcow2-linux-b5773a3616d10bdef60662b8780ded912ee5d7b6.tar.gz kernel-qcow2-linux-b5773a3616d10bdef60662b8780ded912ee5d7b6.tar.xz kernel-qcow2-linux-b5773a3616d10bdef60662b8780ded912ee5d7b6.zip | |
drm/i915/execlists: Suppress mere WAIT preemption
WAIT is occasionally suppressed by virtue of preempted requests being
promoted to NEWCLIENT if they have not all ready received that boost.
Make this consistent for all WAIT boosts that they are not allowed to
preempt executing contexts and are merely granted the right to be at the
front of the queue for the next execution slot. This is in keeping with
the desire that the WAIT boost be a minor tweak that does not give
excessive promotion to its user and open ourselves to trivial abuse.
The problem with the inconsistent WAIT preemption becomes more apparent
as the preemption is propagated across the engines, where one engine may
preempt and the other not, and we be relying on the exact execution
order being consistent across engines (e.g. using HW semaphores to
coordinate parallel execution).
v2: Also protect GuC submission from false preemption loops.
v3: Build bug safeguards and better debug messages for st.
v4: Do the priority bumping in unsubmit (i.e. on preemption/reset
unwind), applying it earlier during submit causes out-of-order execution
combined with execute fences.
v5: Call sw_fence_fini for our dummy request (Matthew)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190228220639.3173-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm/i915/i915_request.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_request.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index a011bf4be48e..c65f6c990fdd 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -358,11 +358,14 @@ void __i915_request_submit(struct i915_request *request) /* We may be recursing from the signal callback of another i915 fence */ spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); + GEM_BUG_ON(test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags)); set_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags); + if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags) && !i915_request_enable_breadcrumb(request)) intel_engine_queue_breadcrumbs(engine); + spin_unlock(&request->lock); engine->emit_fini_breadcrumb(request, @@ -406,10 +409,22 @@ void __i915_request_unsubmit(struct i915_request *request) /* We may be recursing from the signal callback of another i915 fence */ spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); + + /* + * As we do not allow WAIT to preempt inflight requests, + * once we have executed a request, along with triggering + * any execution callbacks, we must preserve its ordering + * within the non-preemptible FIFO. + */ + BUILD_BUG_ON(__NO_PREEMPTION & ~I915_PRIORITY_MASK); /* only internal */ + request->sched.attr.priority |= __NO_PREEMPTION; + if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &request->fence.flags)) i915_request_cancel_breadcrumb(request); + GEM_BUG_ON(!test_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags)); clear_bit(I915_FENCE_FLAG_ACTIVE, &request->fence.flags); + spin_unlock(&request->lock); /* Transfer back from the global per-engine timeline to per-context */ |