[Intel-gfx] [PATCH] drm/i915/guc: Fix revocation of non-persistent contexts
Andrzej Hajda
andrzej.hajda at intel.com
Mon Oct 3 09:30:11 UTC 2022
On 03.10.2022 09:59, Tvrtko Ursulin wrote:
>
> On 30/09/2022 15:52, Andrzej Hajda wrote:
>> On 30.09.2022 11:47, Tvrtko Ursulin wrote:
>>> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>>
>>> Patch which added graceful exit for non-persistent contexts missed the
>>> fact it is not enough to set the exiting flag on a context and let the
>>> backend handle it from there.
>>>
>>> GuC backend cannot handle it because it runs independently in the
>>> firmware and driver might not see the requests ever again. Patch also
>>> missed the fact some usages of intel_context_is_banned in the GuC
>>> backend
>>> needed replacing with newly introduced intel_context_is_schedulable.
>>>
>>> Fix the first issue by calling into backend revoke when we know this is
>>> the last chance to do it. Fix the second issue by replacing
>>> intel_context_is_banned with intel_context_is_schedulable, which should
>>> always be safe since latter is a superset of the former.
>>
>> negation of the latter is a ...?
>
> I did not get what you meant here.
>
>>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>> Fixes: 45c64ecf97ee ("drm/i915: Improve user experience and driver
>>> robustness under SIGINT or similar")
>>> Cc: Andrzej Hajda <andrzej.hajda at intel.com>
>>> Cc: John Harrison <John.C.Harrison at Intel.com>
>>> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
>>> ---
>>> drivers/gpu/drm/i915/gem/i915_gem_context.c | 8 +-----
>>> drivers/gpu/drm/i915/gt/intel_context.c | 14 +++++++---
>>> drivers/gpu/drm/i915/gt/intel_context.h | 8 +-----
>>> .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 26 +++++++++----------
>>> 4 files changed, 25 insertions(+), 31 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> index 0bcde53c50c6..1e29b1e6d186 100644
>>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>>> @@ -1387,14 +1387,8 @@ kill_engines(struct i915_gem_engines *engines,
>>> bool exit, bool persistent)
>>> */
>>> for_each_gem_engine(ce, engines, it) {
>>> struct intel_engine_cs *engine;
>>> - bool skip = false;
>>> - if (exit)
>>> - skip = intel_context_set_exiting(ce);
>>> - else if (!persistent)
>>> - skip = intel_context_exit_nonpersistent(ce, NULL); > -
>>> - if (skip)
>>> + if ((exit || !persistent) && intel_context_revoke(ce))
>>> continue; /* Already marked. */
>>> /*
>>> diff --git a/drivers/gpu/drm/i915/gt/intel_context.c
>>> b/drivers/gpu/drm/i915/gt/intel_context.c
>>> index 654a092ed3d6..398b2a9eed61 100644
>>> --- a/drivers/gpu/drm/i915/gt/intel_context.c
>>> +++ b/drivers/gpu/drm/i915/gt/intel_context.c
>>> @@ -614,13 +614,19 @@ bool intel_context_ban(struct intel_context
>>> *ce, struct i915_request *rq)
>>> return ret;
>>> }
>>> -bool intel_context_exit_nonpersistent(struct intel_context *ce,
>>> - struct i915_request *rq)
>>> +bool intel_context_revoke(struct intel_context *ce)
>>> {
>>> bool ret = intel_context_set_exiting(ce);
>>> - if (ce->ops->revoke)
>>> - ce->ops->revoke(ce, rq, ce->engine->props.preempt_timeout_ms);
>>> + if (!ret && intel_engine_uses_guc(ce->engine)) {
>>> + /*
>>> + * With GuC backend we have to notify it of revocation as soon
>>> + * as the exiting flag is set.
>>> + */
>>> + if (ce->ops->revoke)
>>> + ce->ops->revoke(ce, NULL,
>>> + ce->engine->props.preempt_timeout_ms);
>>> + }
>>
>> Now revoke is called only with GuC, previously it was called also for
>> other backends in case non-exiting/non-persistent, is it OK?
>
> It is okay (execlists has no revoke vfunc, ringbuffer has it but only
> works if target request is known), but agreed it is a bit ugly. I was in
> two minds which way to go. Perhaps it would indeed be cleaner to go
> unconditional. I will resend with that change, copying stable this time
> round (since 6.0 is out), and can keep your r-b?
Yes, please keep r-b.
Regards
Andrzej
>
> Regards,
>
> Tvrtko
>
>>
>>> return ret;
>>> }
>>> diff --git a/drivers/gpu/drm/i915/gt/intel_context.h
>>> b/drivers/gpu/drm/i915/gt/intel_context.h
>>> index 8e2d70630c49..40f8809d14ea 100644
>>> --- a/drivers/gpu/drm/i915/gt/intel_context.h
>>> +++ b/drivers/gpu/drm/i915/gt/intel_context.h
>>> @@ -319,18 +319,12 @@ static inline bool
>>> intel_context_is_schedulable(const struct intel_context *ce)
>>> !test_bit(CONTEXT_BANNED, &ce->flags);
>>> }
>>> -static inline bool intel_context_is_exiting(const struct
>>> intel_context *ce)
>>> -{
>>> - return test_bit(CONTEXT_EXITING, &ce->flags);
>>> -}
>>> -
>>> static inline bool intel_context_set_exiting(struct intel_context *ce)
>>> {
>>> return test_and_set_bit(CONTEXT_EXITING, &ce->flags);
>>> }
>>> -bool intel_context_exit_nonpersistent(struct intel_context *ce,
>>> - struct i915_request *rq);
>>> +bool intel_context_revoke(struct intel_context *ce);
>>> static inline bool
>>> intel_context_force_single_submission(const struct intel_context *ce)
>>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>> b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>> index 0ef295a94060..88a4476b8e92 100644
>>> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
>>> @@ -685,7 +685,7 @@ static int __guc_add_request(struct intel_guc
>>> *guc, struct i915_request *rq)
>>> * Corner case where requests were sitting in the priority list
>>> or a
>>> * request resubmitted after the context was banned.
>>> */
>>> - if (unlikely(intel_context_is_banned(ce))) {
>>> + if (unlikely(!intel_context_is_schedulable(ce))) {
>>> i915_request_put(i915_request_mark_eio(rq));
>>> intel_engine_signal_breadcrumbs(ce->engine);
>>> return 0;
>>> @@ -871,15 +871,15 @@ static int guc_wq_item_append(struct intel_guc
>>> *guc,
>>> struct i915_request *rq)
>>> {
>>> struct intel_context *ce = request_to_scheduling_context(rq);
>>> - int ret = 0;
>>> + int ret;
>>> - if (likely(!intel_context_is_banned(ce))) {
>>> - ret = __guc_wq_item_append(rq);
>>> + if (unlikely(!intel_context_is_schedulable(ce)))
>>> + return 0;
>>> - if (unlikely(ret == -EBUSY)) {
>>> - guc->stalled_request = rq;
>>> - guc->submission_stall_reason = STALL_MOVE_LRC_TAIL;
>>> - }
>>> + ret = __guc_wq_item_append(rq);
>>> + if (unlikely(ret == -EBUSY)) {
>>> + guc->stalled_request = rq;
>>> + guc->submission_stall_reason = STALL_MOVE_LRC_TAIL;
>>> }
>>> return ret;
>>> @@ -898,7 +898,7 @@ static bool multi_lrc_submit(struct i915_request
>>> *rq)
>>> * submitting all the requests generated in parallel.
>>> */
>>> return test_bit(I915_FENCE_FLAG_SUBMIT_PARALLEL,
>>> &rq->fence.flags) ||
>>> - intel_context_is_banned(ce);
>>> + !intel_context_is_schedulable(ce);
>>> }
>>> static int guc_dequeue_one_context(struct intel_guc *guc)
>>> @@ -967,7 +967,7 @@ static int guc_dequeue_one_context(struct
>>> intel_guc *guc)
>>> struct intel_context *ce =
>>> request_to_scheduling_context(last);
>>> if (unlikely(!ctx_id_mapped(guc, ce->guc_id.id) &&
>>> - !intel_context_is_banned(ce))) {
>>> + intel_context_is_schedulable(ce))) {
>>> ret = try_context_registration(ce, false);
>>> if (unlikely(ret == -EPIPE)) {
>>> goto deadlk;
>>> @@ -1577,7 +1577,7 @@ static void guc_reset_state(struct
>>> intel_context *ce, u32 head, bool scrub)
>>> {
>>> struct intel_engine_cs *engine = __context_to_physical_engine(ce);
>>> - if (intel_context_is_banned(ce))
>>> + if (!intel_context_is_schedulable(ce))
>>> return;
>>> GEM_BUG_ON(!intel_context_is_pinned(ce));
>>> @@ -4518,12 +4518,12 @@ static void guc_handle_context_reset(struct
>>> intel_guc *guc,
>>> {
>>> trace_intel_context_reset(ce);
>>> - if (likely(!intel_context_is_banned(ce))) {
>>> + if (likely(intel_context_is_schedulable(ce))) {
>>> capture_error_state(guc, ce);
>>> guc_context_replay(ce);
>>> } else {
>>> drm_info(&guc_to_gt(guc)->i915->drm,
>>> - "Ignoring context reset notification of banned context
>>> 0x%04X on %s",
>>> + "Ignoring context reset notification of exiting context
>>> 0x%04X on %s",
>>
>> With small clarifications:
>>
>> Reviewed-by: Andrzej Hajda <andrzej.hajda at intel.com>
>>
>> Regards
>> Andrzej
>>
>>
>>> ce->guc_id.id, ce->engine->name);
>>> }
>>> }
>>
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