Re: [Intel-gfx] [PATCH 50/51] drm/i915/guc: Implement GuC priority management

Daniele Ceraolo Spurio
2021-07-22T21:50:37Z

<snip>

>>> @@ -1756,15 +1796,119 @@ static int guc_context_alloc(struct intel_context *ce)
>>> return lrc_alloc(ce, ce->engine);
>>> }
>>> +static void guc_context_set_prio(struct intel_guc *guc,
>>> + struct intel_context *ce,
>>> + u8 prio)
>>> +{
>>> + u32 action[] = {
>>> + INTEL_GUC_ACTION_SET_CONTEXT_PRIORITY,
>>> + ce->guc_id,
>>> + prio,
>>> + };
>>> +
>>> + GEM_BUG_ON(prio < GUC_CLIENT_PRIORITY_KMD_HIGH ||
>>> + prio > GUC_CLIENT_PRIORITY_NORMAL);
>>> +
>>> + if (ce->guc_prio == prio || submission_disabled(guc) ||
>>> + !context_registered(ce))
>>> + return;
>>> +
>>> + guc_submission_send_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);
>>> +
>>> + ce->guc_prio = prio;
>>> + trace_intel_context_set_prio(ce);
>>> +}
>>> +
>>> +static inline u8 map_i915_prio_to_guc_prio(int prio)
>>> +{
>>> + if (prio == I915_PRIORITY_NORMAL)
>>> + return GUC_CLIENT_PRIORITY_KMD_NORMAL;
>>> + else if (prio < I915_PRIORITY_NORMAL)
>>> + return GUC_CLIENT_PRIORITY_NORMAL;
>>> + else if (prio != I915_PRIORITY_BARRIER)
>> Shouldn't this be I915_PRIORITY_UNPREEMPTABLE?
>>
> No, I915_PRIORITY_UNPREEMPTABLE is an execlists only concept.

then we need a

/* we don't expect umpreemptable submissions with the GuC */
GEM_BUG_ON(prio == I915_PRIORITY_UNPREEMPTABLE)

or something, because that prio level would be assigned incorrectly
otherwise.

Daniele