Re: [PATCH 30/47] drm/i915/guc: Direct all breadcrumbs for a class to single breadcrumbs

On 6/24/2021 00:04, 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.

Signed-off-by: Matthew Brost matthew.brost@intel.com CC: John Harrison John.C.Harrison@Intel.com

---

drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 41 +++++------- drivers/gpu/drm/i915/gt/intel_breadcrumbs.h | 14 +++- .../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 | 1 - .../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, 131 insertions(+), 36 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..72105b74663d 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h @@ -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..a4e146684be8 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>

+typedef u8 intel_engine_mask_t;

Seems like the wrong place for this. Can it be moved to gt/intel_engine_types.h instead?

• /*
  • 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 923eaee627b3..e9e0657f847a 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 d13b1716c29e..69245670b8b0 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;

@@ -947,7 +947,7 @@ 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);

@@ -1264,6 +1264,30 @@ 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 1dc59e6c9a92..e7cb6a06db9d 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h @@ -64,7 +64,6 @@ struct intel_gt; struct intel_ring; struct intel_uncore;

-typedef u8 intel_engine_mask_t;

Oh.

The following fixes this for me: diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h index 3ce5ce270b04..ac5cdd6ff3f4 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.h @@ -10,6 +10,7 @@  #include <linux/irq_work.h>

#include "intel_engine_types.h" +#include "gt/intel_breadcrumbs_types.h"

struct drm_printer;  struct i915_request; diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h index 3a084ce8ff5e..260ccd5c1573 100644 --- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h +++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs_types.h @@ -11,6 +11,8 @@  #include <linux/spinlock.h>  #include <linux/types.h>

+#include "gt/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 diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h index 1cb9c3b70b29..da15b8b3c1f7 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"

John.

#define ALL_ENGINES ((intel_engine_mask_t)~0ul)

struct intel_hw_status_page { diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 9cfb8800a0e6..c10ea6080752 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -3419,7 +3419,7 @@ 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 d1badd7137b7..83058df5ba01 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -1074,6 +1074,9 @@ 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);

@@ -1377,6 +1380,62 @@ 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;

@@ -1600,6 +1659,7 @@ 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);

@@ -1839,11 +1899,6 @@ 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");

@@ -1892,6 +1947,8 @@ 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;