Re: [Intel-gfx] [PATCH 23/51] drm/i915/guc: Direct all breadcrumbs for a class to single breadcrumbs

John Harrison
2021-07-20T19:45:49Z

On 7/16/2021 13:16, Matthew Brost wrote:
> With GuC virtual engines the physical engine which a request executes
> and completes on isn't known to the i915. Therefore we can't attach a
> request to a physical engines breadcrumbs. To work around this we create
> a single breadcrumbs per engine class when using GuC submission and
> direct all physical engine interrupts to this breadcrumbs.
>
> v2:
> (John H)
> - Rework header file structure so intel_engine_mask_t can be in
> intel_engine_types.h
>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> CC: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>

> ---
> drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 41 +++++-------
> drivers/gpu/drm/i915/gt/intel_breadcrumbs.h | 16 ++++-
> .../gpu/drm/i915/gt/intel_breadcrumbs_types.h | 7 ++
> drivers/gpu/drm/i915/gt/intel_engine.h | 3 +
> drivers/gpu/drm/i915/gt/intel_engine_cs.c | 28 +++++++-
> drivers/gpu/drm/i915/gt/intel_engine_types.h | 2 +-
> .../drm/i915/gt/intel_execlists_submission.c | 2 +-
> drivers/gpu/drm/i915/gt/mock_engine.c | 4 +-
> .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 67 +++++++++++++++++--
> 9 files changed, 133 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> index 38cc42783dfb..2007dc6f6b99 100644
> --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
> @@ -15,28 +15,14 @@
> #include "intel_gt_pm.h"
> #include "intel_gt_requests.h"
>
> -static bool irq_enable(struct intel_engine_cs *engine)
> +static bool irq_enable(struct intel_breadcrumbs *b)
> {
> - if (!engine->irq_enable)
> - return false;
> -
> - /* Caller disables interrupts */
> - spin_lock(&engine->gt->irq_lock);
> - engine->irq_enable(engine);
> - spin_unlock(&engine->gt->irq_lock);
> -
> - return true;
> + return intel_engine_irq_enable(b->irq_engine);
> }
>
> -static void irq_disable(struct intel_engine_cs *engine)
> +static void irq_disable(struct intel_breadcrumbs *b)
> {
> - if (!engine->irq_disable)
> - return;
> -
> - /* Caller disables interrupts */
> - spin_lock(&engine->gt->irq_lock);
> - engine->irq_disable(engine);
> - spin_unlock(&engine->gt->irq_lock);
> + intel_engine_irq_disable(b->irq_engine);
> }
>
> static void __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
> @@ -57,7 +43,7 @@ static void __intel_breadcrumbs_arm_irq(struct intel_breadcrumbs *b)
> WRITE_ONCE(b->irq_armed, true);
>
> /* Requests may have completed before we could enable the interrupt. */
> - if (!b->irq_enabled++ && irq_enable(b->irq_engine))
> + if (!b->irq_enabled++ && b->irq_enable(b))
> irq_work_queue(&b->irq_work);
> }
>
> @@ -76,7 +62,7 @@ static void __intel_breadcrumbs_disarm_irq(struct intel_breadcrumbs *b)
> {
> GEM_BUG_ON(!b->irq_enabled);
> if (!--b->irq_enabled)
> - irq_disable(b->irq_engine);
> + b->irq_disable(b);
>
> WRITE_ONCE(b->irq_armed, false);
> intel_gt_pm_put_async(b->irq_engine->gt);
> @@ -281,7 +267,7 @@ intel_breadcrumbs_create(struct intel_engine_cs *irq_engine)
> if (!b)
> return NULL;
>
> - b->irq_engine = irq_engine;
> + kref_init(&b->ref);
>
> spin_lock_init(&b->signalers_lock);
> INIT_LIST_HEAD(&b->signalers);
> @@ -290,6 +276,10 @@ intel_breadcrumbs_create(struct intel_engine_cs *irq_engine)
> spin_lock_init(&b->irq_lock);
> init_irq_work(&b->irq_work, signal_irq_work);
>
> + b->irq_engine = irq_engine;
> + b->irq_enable = irq_enable;
> + b->irq_disable = irq_disable;
> +
> return b;
> }
>
> @@ -303,9 +293,9 @@ void intel_breadcrumbs_reset(struct intel_breadcrumbs *b)
> spin_lock_irqsave(&b->irq_lock, flags);
>
> if (b->irq_enabled)
> - irq_enable(b->irq_engine);
> + b->irq_enable(b);
> else
> - irq_disable(b->irq_engine);
> + b->irq_disable(b);
>
> spin_unlock_irqrestore(&b->irq_lock, flags);
> }
> @@ -325,11 +315,14 @@ void __intel_breadcrumbs_park(struct intel_breadcrumbs *b)
> }
> }
>
> -void intel_breadcrumbs_free(struct intel_breadcrumbs *b)
> +void intel_breadcrumbs_free(struct kref *kref)
> {
> + struct intel_breadcrumbs *b = container_of(kref, typeof(*b), ref);
> +
> irq_work_sync(&b->irq_work);
> GEM_BUG_ON(!list_empty(&b->signalers));
> GEM_BUG_ON(b->irq_armed);
> +
> kfree(b);
> }
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
> index 3ce5ce270b04..be0d4f379a85 100644
> --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
> +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h
> @@ -9,7 +9,7 @@
> #include <linux/atomic.h>
> #include <linux/irq_work.h>
>
> -#include "intel_engine_types.h"
> +#include "intel_breadcrumbs_types.h"
>
> struct drm_printer;
> struct i915_request;
> @@ -17,7 +17,7 @@ struct intel_breadcrumbs;
>
> struct intel_breadcrumbs *
> intel_breadcrumbs_create(struct intel_engine_cs *irq_engine);
> -void intel_breadcrumbs_free(struct intel_breadcrumbs *b);
> +void intel_breadcrumbs_free(struct kref *kref);
>
> void intel_breadcrumbs_reset(struct intel_breadcrumbs *b);
> void __intel_breadcrumbs_park(struct intel_breadcrumbs *b);
> @@ -48,4 +48,16 @@ void i915_request_cancel_breadcrumb(struct i915_request *request);
> void intel_context_remove_breadcrumbs(struct intel_context *ce,
> struct intel_breadcrumbs *b);
>
> +static inline struct intel_breadcrumbs *
> +intel_breadcrumbs_get(struct intel_breadcrumbs *b)
> +{
> + kref_get(&b->ref);
> + return b;
> +}
> +
> +static inline void intel_breadcrumbs_put(struct intel_breadcrumbs *b)
> +{
> + kref_put(&b->ref, intel_breadcrumbs_free);
> +}
> +
> #endif /* __INTEL_BREADCRUMBS__ */
> diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h
> index 3a084ce8ff5e..72dfd3748c4c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h
> @@ -7,10 +7,13 @@
> #define __INTEL_BREADCRUMBS_TYPES__
>
> #include <linux/irq_work.h>
> +#include <linux/kref.h>
> #include <linux/list.h>
> #include <linux/spinlock.h>
> #include <linux/types.h>
>
> +#include "intel_engine_types.h"
> +
> /*
> * Rather than have every client wait upon all user interrupts,
> * with the herd waking after every interrupt and each doing the
> @@ -29,6 +32,7 @@
> * the overhead of waking that client is much preferred.
> */
> struct intel_breadcrumbs {
> + struct kref ref;
> atomic_t active;
>
> spinlock_t signalers_lock; /* protects the list of signalers */
> @@ -42,7 +46,10 @@ struct intel_breadcrumbs {
> bool irq_armed;
>
> /* Not all breadcrumbs are attached to physical HW */
> + intel_engine_mask_t engine_mask;
> struct intel_engine_cs *irq_engine;
> + bool (*irq_enable)(struct intel_breadcrumbs *b);
> + void (*irq_disable)(struct intel_breadcrumbs *b);
> };
>
> #endif /* __INTEL_BREADCRUMBS_TYPES__ */
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
> index 9fec0aca5f4b..edbde6171bca 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine.h
> @@ -212,6 +212,9 @@ void intel_engine_get_instdone(const struct intel_engine_cs *engine,
>
> void intel_engine_init_execlists(struct intel_engine_cs *engine);
>
> +bool intel_engine_irq_enable(struct intel_engine_cs *engine);
> +void intel_engine_irq_disable(struct intel_engine_cs *engine);
> +
> static inline void __intel_engine_reset(struct intel_engine_cs *engine,
> bool stalled)
> {
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> index b7292d5cb7da..d95d666407f5 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
> @@ -739,7 +739,7 @@ static int engine_setup_common(struct intel_engine_cs *engine)
> err_cmd_parser:
> i915_sched_engine_put(engine->sched_engine);
> err_sched_engine:
> - intel_breadcrumbs_free(engine->breadcrumbs);
> + intel_breadcrumbs_put(engine->breadcrumbs);
> err_status:
> cleanup_status_page(engine);
> return err;
> @@ -948,7 +948,7 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine)
> GEM_BUG_ON(!list_empty(&engine->sched_engine->requests));
>
> i915_sched_engine_put(engine->sched_engine);
> - intel_breadcrumbs_free(engine->breadcrumbs);
> + intel_breadcrumbs_put(engine->breadcrumbs);
>
> intel_engine_fini_retire(engine);
> intel_engine_cleanup_cmd_parser(engine);
> @@ -1265,6 +1265,30 @@ bool intel_engines_are_idle(struct intel_gt *gt)
> return true;
> }
>
> +bool intel_engine_irq_enable(struct intel_engine_cs *engine)
> +{
> + if (!engine->irq_enable)
> + return false;
> +
> + /* Caller disables interrupts */
> + spin_lock(&engine->gt->irq_lock);
> + engine->irq_enable(engine);
> + spin_unlock(&engine->gt->irq_lock);
> +
> + return true;
> +}
> +
> +void intel_engine_irq_disable(struct intel_engine_cs *engine)
> +{
> + if (!engine->irq_disable)
> + return;
> +
> + /* Caller disables interrupts */
> + spin_lock(&engine->gt->irq_lock);
> + engine->irq_disable(engine);
> + spin_unlock(&engine->gt->irq_lock);
> +}
> +
> void intel_engines_reset_default_submission(struct intel_gt *gt)
> {
> struct intel_engine_cs *engine;
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> index 8ad304b2f2e4..03a81e8d87f4 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> @@ -21,7 +21,6 @@
> #include "i915_pmu.h"
> #include "i915_priolist_types.h"
> #include "i915_selftest.h"
> -#include "intel_breadcrumbs_types.h"
> #include "intel_sseu.h"
> #include "intel_timeline_types.h"
> #include "intel_uncore.h"
> @@ -63,6 +62,7 @@ struct i915_sched_engine;
> struct intel_gt;
> struct intel_ring;
> struct intel_uncore;
> +struct intel_breadcrumbs;
>
> typedef u8 intel_engine_mask_t;
> #define ALL_ENGINES ((intel_engine_mask_t)~0ul)
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index 920707e22eb0..abe48421fd7a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -3407,7 +3407,7 @@ static void rcu_virtual_context_destroy(struct work_struct *wrk)
> intel_context_fini(&ve->context);
>
> if (ve->base.breadcrumbs)
> - intel_breadcrumbs_free(ve->base.breadcrumbs);
> + intel_breadcrumbs_put(ve->base.breadcrumbs);
> if (ve->base.sched_engine)
> i915_sched_engine_put(ve->base.sched_engine);
> intel_engine_free_request_pool(&ve->base);
> diff --git a/drivers/gpu/drm/i915/gt/mock_engine.c b/drivers/gpu/drm/i915/gt/mock_engine.c
> index 9203c766db80..fc5a65ab1937 100644
> --- a/drivers/gpu/drm/i915/gt/mock_engine.c
> +++ b/drivers/gpu/drm/i915/gt/mock_engine.c
> @@ -284,7 +284,7 @@ static void mock_engine_release(struct intel_engine_cs *engine)
> GEM_BUG_ON(timer_pending(&mock->hw_delay));
>
> i915_sched_engine_put(engine->sched_engine);
> - intel_breadcrumbs_free(engine->breadcrumbs);
> + intel_breadcrumbs_put(engine->breadcrumbs);
>
> intel_context_unpin(engine->kernel_context);
> intel_context_put(engine->kernel_context);
> @@ -376,7 +376,7 @@ int mock_engine_init(struct intel_engine_cs *engine)
> return 0;
>
> err_breadcrumbs:
> - intel_breadcrumbs_free(engine->breadcrumbs);
> + intel_breadcrumbs_put(engine->breadcrumbs);
> err_schedule:
> i915_sched_engine_put(engine->sched_engine);
> return -ENOMEM;
> 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 372e0dc7617a..9f28899ff17f 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -1076,6 +1076,9 @@ static void __guc_context_destroy(struct intel_context *ce)
> struct guc_virtual_engine *ve =
> container_of(ce, typeof(*ve), context);
>
> + if (ve->base.breadcrumbs)
> + intel_breadcrumbs_put(ve->base.breadcrumbs);
> +
> kfree(ve);
> } else {
> intel_context_free(ce);
> @@ -1366,6 +1369,62 @@ static const struct intel_context_ops virtual_guc_context_ops = {
> .get_sibling = guc_virtual_get_sibling,
> };
>
> +static bool
> +guc_irq_enable_breadcrumbs(struct intel_breadcrumbs *b)
> +{
> + struct intel_engine_cs *sibling;
> + intel_engine_mask_t tmp, mask = b->engine_mask;
> + bool result = false;
> +
> + for_each_engine_masked(sibling, b->irq_engine->gt, mask, tmp)
> + result |= intel_engine_irq_enable(sibling);
> +
> + return result;
> +}
> +
> +static void
> +guc_irq_disable_breadcrumbs(struct intel_breadcrumbs *b)
> +{
> + struct intel_engine_cs *sibling;
> + intel_engine_mask_t tmp, mask = b->engine_mask;
> +
> + for_each_engine_masked(sibling, b->irq_engine->gt, mask, tmp)
> + intel_engine_irq_disable(sibling);
> +}
> +
> +static void guc_init_breadcrumbs(struct intel_engine_cs *engine)
> +{
> + int i;
> +
> + /*
> + * In GuC submission mode we do not know which physical engine a request
> + * will be scheduled on, this creates a problem because the breadcrumb
> + * interrupt is per physical engine. To work around this we attach
> + * requests and direct all breadcrumb interrupts to the first instance
> + * of an engine per class. In addition all breadcrumb interrupts are
> + * enabled / disabled across an engine class in unison.
> + */
> + for (i = 0; i < MAX_ENGINE_INSTANCE; ++i) {
> + struct intel_engine_cs *sibling =
> + engine->gt->engine_class[engine->class][i];
> +
> + if (sibling) {
> + if (engine->breadcrumbs != sibling->breadcrumbs) {
> + intel_breadcrumbs_put(engine->breadcrumbs);
> + engine->breadcrumbs =
> + intel_breadcrumbs_get(sibling->breadcrumbs);
> + }
> + break;
> + }
> + }
> +
> + if (engine->breadcrumbs) {
> + engine->breadcrumbs->engine_mask |= engine->mask;
> + engine->breadcrumbs->irq_enable = guc_irq_enable_breadcrumbs;
> + engine->breadcrumbs->irq_disable = guc_irq_disable_breadcrumbs;
> + }
> +}
> +
> static void sanitize_hwsp(struct intel_engine_cs *engine)
> {
> struct intel_timeline *tl;
> @@ -1589,6 +1648,7 @@ int intel_guc_submission_setup(struct intel_engine_cs *engine)
>
> guc_default_vfuncs(engine);
> guc_default_irqs(engine);
> + guc_init_breadcrumbs(engine);
>
> if (engine->class == RENDER_CLASS)
> rcs_submission_override(engine);
> @@ -1831,11 +1891,6 @@ guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count)
> ve->base.instance = I915_ENGINE_CLASS_INVALID_VIRTUAL;
> ve->base.uabi_instance = I915_ENGINE_CLASS_INVALID_VIRTUAL;
> ve->base.saturated = ALL_ENGINES;
> - ve->base.breadcrumbs = intel_breadcrumbs_create(&ve->base);
> - if (!ve->base.breadcrumbs) {
> - kfree(ve);
> - return ERR_PTR(-ENOMEM);
> - }
>
> snprintf(ve->base.name, sizeof(ve->base.name), "virtual");
>
> @@ -1884,6 +1939,8 @@ guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count)
> sibling->emit_fini_breadcrumb;
> ve->base.emit_fini_breadcrumb_dw =
> sibling->emit_fini_breadcrumb_dw;
> + ve->base.breadcrumbs =
> + intel_breadcrumbs_get(sibling->breadcrumbs);
>
> ve->base.flags |= sibling->flags;