Re: [Intel-gfx] [PATCH 22/47] drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC

[John Harrison <john.c.harrison@intel.com>]

On 6/24/2021 00:04, Matthew Brost wrote:
> When running the GuC the GPU can't be considered idle if the GuC still
> has contexts pinned. As such, a call has been added in
> intel_gt_wait_for_idle to idle the UC and in turn the GuC by waiting for
> the number of unpinned contexts to go to zero.
>
> v2: rtimeout -> remaining_timeout
>
> Cc: John Harrison <john.c.harrison@intel.com>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_mman.c      |  3 +-
>   drivers/gpu/drm/i915/gt/intel_gt.c            | 19 ++++
>   drivers/gpu/drm/i915/gt/intel_gt.h            |  2 +
>   drivers/gpu/drm/i915/gt/intel_gt_requests.c   | 22 ++---
>   drivers/gpu/drm/i915/gt/intel_gt_requests.h   |  9 +-
>   drivers/gpu/drm/i915/gt/uc/intel_guc.h        |  4 +
>   drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c     |  1 +
>   drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h     |  4 +
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 88 ++++++++++++++++++-
>   drivers/gpu/drm/i915/gt/uc/intel_uc.h         |  5 ++
>   drivers/gpu/drm/i915/i915_debugfs.c           |  1 +
>   drivers/gpu/drm/i915/i915_gem_evict.c         |  1 +
>   .../gpu/drm/i915/selftests/igt_live_test.c    |  2 +-
>   .../gpu/drm/i915/selftests/mock_gem_device.c  |  3 +-
>   14 files changed, 137 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> index 2fd155742bd2..335b955d5b4b 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> @@ -644,7 +644,8 @@ mmap_offset_attach(struct drm_i915_gem_object *obj,
>   		goto insert;
>   
>   	/* Attempt to reap some mmap space from dead objects */
> -	err = intel_gt_retire_requests_timeout(&i915->gt, MAX_SCHEDULE_TIMEOUT);
> +	err = intel_gt_retire_requests_timeout(&i915->gt, MAX_SCHEDULE_TIMEOUT,
> +					       NULL);
>   	if (err)
>   		goto err;
>   
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
> index e714e21c0a4d..acfdd53b2678 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
> @@ -585,6 +585,25 @@ static void __intel_gt_disable(struct intel_gt *gt)
>   	GEM_BUG_ON(intel_gt_pm_is_awake(gt));
>   }
>   
> +int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout)
> +{
> +	long remaining_timeout;
> +
> +	/* If the device is asleep, we have no requests outstanding */
> +	if (!intel_gt_pm_is_awake(gt))
> +		return 0;
> +
> +	while ((timeout = intel_gt_retire_requests_timeout(gt, timeout,
> +							   &remaining_timeout)) > 0) {
> +		cond_resched();
> +		if (signal_pending(current))
> +			return -EINTR;
> +	}
> +
> +	return timeout ? timeout : intel_uc_wait_for_idle(&gt->uc,
> +							  remaining_timeout);
> +}
> +
>   int intel_gt_init(struct intel_gt *gt)
>   {
>   	int err;
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.h b/drivers/gpu/drm/i915/gt/intel_gt.h
> index e7aabe0cc5bf..74e771871a9b 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt.h
> @@ -48,6 +48,8 @@ void intel_gt_driver_release(struct intel_gt *gt);
>   
>   void intel_gt_driver_late_release(struct intel_gt *gt);
>   
> +int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout);
> +
>   void intel_gt_check_and_clear_faults(struct intel_gt *gt);
>   void intel_gt_clear_error_registers(struct intel_gt *gt,
>   				    intel_engine_mask_t engine_mask);
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
> index 647eca9d867a..39f5e824dac5 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
> @@ -13,6 +13,7 @@
>   #include "intel_gt_pm.h"
>   #include "intel_gt_requests.h"
>   #include "intel_timeline.h"
> +#include "uc/intel_uc.h"
Why is this needed?

>   
>   static bool retire_requests(struct intel_timeline *tl)
>   {
> @@ -130,7 +131,8 @@ void intel_engine_fini_retire(struct intel_engine_cs *engine)
>   	GEM_BUG_ON(engine->retire);
>   }
>   
> -long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout)
> +long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout,
> +				      long *remaining_timeout)
>   {
>   	struct intel_gt_timelines *timelines = &gt->timelines;
>   	struct intel_timeline *tl, *tn;
> @@ -195,22 +197,10 @@ out_active:	spin_lock(&timelines->lock);
>   	if (flush_submission(gt, timeout)) /* Wait, there's more! */
>   		active_count++;
>   
> -	return active_count ? timeout : 0;
> -}
> -
> -int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout)
> -{
> -	/* If the device is asleep, we have no requests outstanding */
> -	if (!intel_gt_pm_is_awake(gt))
> -		return 0;
> -
> -	while ((timeout = intel_gt_retire_requests_timeout(gt, timeout)) > 0) {
> -		cond_resched();
> -		if (signal_pending(current))
> -			return -EINTR;
> -	}
> +	if (remaining_timeout)
> +		*remaining_timeout = timeout;
>   
> -	return timeout;
> +	return active_count ? timeout : 0;
>   }
>   
>   static void retire_work_handler(struct work_struct *work)
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.h b/drivers/gpu/drm/i915/gt/intel_gt_requests.h
> index fcc30a6e4fe9..51dbe0e3294e 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.h
> @@ -6,14 +6,17 @@
>   #ifndef INTEL_GT_REQUESTS_H
>   #define INTEL_GT_REQUESTS_H
>   
> +#include <stddef.h>
> +
Why is this needed?

>   struct intel_engine_cs;
>   struct intel_gt;
>   struct intel_timeline;
>   
> -long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout);
> +long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout,
> +				      long *remaining_timeout);
>   static inline void intel_gt_retire_requests(struct intel_gt *gt)
>   {
> -	intel_gt_retire_requests_timeout(gt, 0);
> +	intel_gt_retire_requests_timeout(gt, 0, NULL);
>   }
>   
>   void intel_engine_init_retire(struct intel_engine_cs *engine);
> @@ -21,8 +24,6 @@ void intel_engine_add_retire(struct intel_engine_cs *engine,
>   			     struct intel_timeline *tl);
>   void intel_engine_fini_retire(struct intel_engine_cs *engine);
>   
> -int intel_gt_wait_for_idle(struct intel_gt *gt, long timeout);
> -
>   void intel_gt_init_requests(struct intel_gt *gt);
>   void intel_gt_park_requests(struct intel_gt *gt);
>   void intel_gt_unpark_requests(struct intel_gt *gt);
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> index 24e7a924134e..22eb1e9cca41 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
> @@ -38,6 +38,8 @@ struct intel_guc {
>   	spinlock_t irq_lock;
>   	unsigned int msg_enabled_mask;
>   
> +	atomic_t outstanding_submission_g2h;
> +
>   	struct {
>   		void (*reset)(struct intel_guc *guc);
>   		void (*enable)(struct intel_guc *guc);
> @@ -238,6 +240,8 @@ static inline void intel_guc_disable_msg(struct intel_guc *guc, u32 mask)
>   	spin_unlock_irq(&guc->irq_lock);
>   }
>   
> +int intel_guc_wait_for_idle(struct intel_guc *guc, long timeout);
> +
>   int intel_guc_reset_engine(struct intel_guc *guc,
>   			   struct intel_engine_cs *engine);
>   
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> index a60970e85635..e0f92e28350c 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> @@ -109,6 +109,7 @@ void intel_guc_ct_init_early(struct intel_guc_ct *ct)
>   	INIT_LIST_HEAD(&ct->requests.incoming);
>   	INIT_WORK(&ct->requests.worker, ct_incoming_request_worker_func);
>   	tasklet_setup(&ct->receive_tasklet, ct_receive_tasklet_func);
> +	init_waitqueue_head(&ct->wq);
>   }
>   
>   static inline const char *guc_ct_buffer_type_to_str(u32 type)
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> index 660bf37238e2..ab1b79ab960b 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> @@ -10,6 +10,7 @@
>   #include <linux/spinlock.h>
>   #include <linux/workqueue.h>
>   #include <linux/ktime.h>
> +#include <linux/wait.h>
>   
>   #include "intel_guc_fwif.h"
>   
> @@ -68,6 +69,9 @@ struct intel_guc_ct {
>   
>   	struct tasklet_struct receive_tasklet;
>   
> +	/** @wq: wait queue for g2h chanenl */
> +	wait_queue_head_t wq;
> +
>   	struct {
>   		u16 last_fence; /* last fence used to send request */
>   
> 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 ef24758c4266..d1a28283a9ae 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -254,6 +254,74 @@ static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
>   	xa_store_irq(&guc->context_lookup, id, ce, GFP_ATOMIC);
>   }
>   
> +static int guc_submission_busy_loop(struct intel_guc* guc,
I think this name is misleading. It would be better as 
guc_submission_send_busy_loop.

> +				    const u32 *action,
> +				    u32 len,
> +				    u32 g2h_len_dw,
> +				    bool loop)
> +{
> +	int err;
> +
> +	err = intel_guc_send_busy_loop(guc, action, len, g2h_len_dw, loop);
> +
> +	if (!err && g2h_len_dw)
> +		atomic_inc(&guc->outstanding_submission_g2h);
> +
> +	return err;
> +}
> +
> +static int guc_wait_for_pending_msg(struct intel_guc *guc,
> +				    atomic_t *wait_var,
> +				    bool interruptible,
> +				    long timeout)
> +{
> +	const int state = interruptible ?
> +		TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
> +	DEFINE_WAIT(wait);
> +
> +	might_sleep();
> +	GEM_BUG_ON(timeout < 0);
> +
> +	if (!atomic_read(wait_var))
> +		return 0;
> +
> +	if (!timeout)
> +		return -ETIME;
> +
> +	for (;;) {
> +		prepare_to_wait(&guc->ct.wq, &wait, state);
> +
> +		if (!atomic_read(wait_var))
> +			break;
> +
> +		if (signal_pending_state(state, current)) {
> +			timeout = -ERESTARTSYS;
> +			break;
> +		}
> +
> +		if (!timeout) {
> +			timeout = -ETIME;
> +			break;
> +		}
> +
> +		timeout = io_schedule_timeout(timeout);
> +	}
> +	finish_wait(&guc->ct.wq, &wait);
> +
> +	return (timeout < 0) ? timeout : 0;
> +}
> +
> +int intel_guc_wait_for_idle(struct intel_guc *guc, long timeout)
> +{
> +	bool interruptible = true;
> +
> +	if (unlikely(timeout < 0))
> +		timeout = -timeout, interruptible = false;
Why is this a comma bridged statement rather than just two lines with 
braces on the if?

And overloading negative timeouts to mean non-interruptible seems 
unnecessarily convoluted in the first place. Why not just have an 
interruptible parameter? I'm also not seeing how the timeout gets to be 
negative in the first place?


> +
> +	return guc_wait_for_pending_msg(guc, &guc->outstanding_submission_g2h,
> +					interruptible, timeout);
> +}
> +
>   static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
>   {
>   	int err;
> @@ -280,6 +348,7 @@ static int guc_add_request(struct intel_guc *guc, struct i915_request *rq)
>   
>   	err = intel_guc_send_nb(guc, action, len, g2h_len_dw);
>   	if (!enabled && !err) {
> +		atomic_inc(&guc->outstanding_submission_g2h);
>   		set_context_enabled(ce);
>   	} else if (!enabled) {
>   		clr_context_pending_enable(ce);
> @@ -731,7 +800,7 @@ static int __guc_action_register_context(struct intel_guc *guc,
>   		offset,
>   	};
>   
> -	return intel_guc_send_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);
> +	return guc_submission_busy_loop(guc, action, ARRAY_SIZE(action), 0, true);
>   }
>   
>   static int register_context(struct intel_context *ce)
> @@ -751,7 +820,7 @@ static int __guc_action_deregister_context(struct intel_guc *guc,
>   		guc_id,
>   	};
>   
> -	return intel_guc_send_busy_loop(guc, action, ARRAY_SIZE(action),
> +	return guc_submission_busy_loop(guc, action, ARRAY_SIZE(action),
>   					G2H_LEN_DW_DEREGISTER_CONTEXT, true);
>   }
>   
> @@ -868,7 +937,9 @@ static int guc_context_pin(struct intel_context *ce, void *vaddr)
>   
>   static void guc_context_unpin(struct intel_context *ce)
>   {
> -	unpin_guc_id(ce_to_guc(ce), ce);
> +	struct intel_guc *guc = ce_to_guc(ce);
> +
> +	unpin_guc_id(guc, ce);
Should this be part of this patch?

>   	lrc_unpin(ce);
>   }
>   
> @@ -891,7 +962,7 @@ static void __guc_context_sched_disable(struct intel_guc *guc,
>   
>   	intel_context_get(ce);
>   
> -	intel_guc_send_busy_loop(guc, action, ARRAY_SIZE(action),
> +	guc_submission_busy_loop(guc, action, ARRAY_SIZE(action),
>   				 G2H_LEN_DW_SCHED_CONTEXT_MODE_SET, true);
>   }
>   
> @@ -1433,6 +1504,12 @@ g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
>   	return ce;
>   }
>   
> +static void decr_outstanding_submission_g2h(struct intel_guc *guc)
> +{
> +	if (atomic_dec_and_test(&guc->outstanding_submission_g2h))
> +		wake_up_all(&guc->ct.wq);
> +}
> +
>   int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
>   					  const u32 *msg,
>   					  u32 len)
> @@ -1468,6 +1545,8 @@ int intel_guc_deregister_done_process_msg(struct intel_guc *guc,
>   		lrc_destroy(&ce->ref);
>   	}
>   
> +	decr_outstanding_submission_g2h(guc);
> +
>   	return 0;
>   }
>   
> @@ -1516,6 +1595,7 @@ int intel_guc_sched_done_process_msg(struct intel_guc *guc,
>   		spin_unlock_irqrestore(&ce->guc_state.lock, flags);
>   	}
>   
> +	decr_outstanding_submission_g2h(guc);
>   	intel_context_put(ce);
>   
>   	return 0;
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.h b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> index 9c954c589edf..c4cef885e984 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
> @@ -81,6 +81,11 @@ uc_state_checkers(guc, guc_submission);
>   #undef uc_state_checkers
>   #undef __uc_state_checker
>   
> +static inline int intel_uc_wait_for_idle(struct intel_uc *uc, long timeout)
> +{
> +	return intel_guc_wait_for_idle(&uc->guc, timeout);
> +}
> +
>   #define intel_uc_ops_function(_NAME, _OPS, _TYPE, _RET) \
>   static inline _TYPE intel_uc_##_NAME(struct intel_uc *uc) \
>   { \
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index cc745751ac53..277800987bf8 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -36,6 +36,7 @@
>   #include "gt/intel_gt_clock_utils.h"
>   #include "gt/intel_gt.h"
>   #include "gt/intel_gt_pm.h"
> +#include "gt/intel_gt.h"
All of these extra includes seem incorrect. There is no code change in 
any of the files below that would warrant a new include.

John.


>   #include "gt/intel_gt_requests.h"
>   #include "gt/intel_reset.h"
>   #include "gt/intel_rc6.h"
> diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
> index 4d2d59a9942b..2b73ddb11c66 100644
> --- a/drivers/gpu/drm/i915/i915_gem_evict.c
> +++ b/drivers/gpu/drm/i915/i915_gem_evict.c
> @@ -27,6 +27,7 @@
>    */
>   
>   #include "gem/i915_gem_context.h"
> +#include "gt/intel_gt.h"
>   #include "gt/intel_gt_requests.h"
>   
>   #include "i915_drv.h"
> diff --git a/drivers/gpu/drm/i915/selftests/igt_live_test.c b/drivers/gpu/drm/i915/selftests/igt_live_test.c
> index c130010a7033..1c721542e277 100644
> --- a/drivers/gpu/drm/i915/selftests/igt_live_test.c
> +++ b/drivers/gpu/drm/i915/selftests/igt_live_test.c
> @@ -5,7 +5,7 @@
>    */
>   
>   #include "i915_drv.h"
> -#include "gt/intel_gt_requests.h"
> +#include "gt/intel_gt.h"
>   
>   #include "../i915_selftest.h"
>   #include "igt_flush_test.h"
> diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> index d189c4bd4bef..4f8180146888 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> @@ -52,7 +52,8 @@ void mock_device_flush(struct drm_i915_private *i915)
>   	do {
>   		for_each_engine(engine, gt, id)
>   			mock_engine_flush(engine);
> -	} while (intel_gt_retire_requests_timeout(gt, MAX_SCHEDULE_TIMEOUT));
> +	} while (intel_gt_retire_requests_timeout(gt, MAX_SCHEDULE_TIMEOUT,
> +						  NULL));
>   }
>   
>   static void mock_device_release(struct drm_device *dev)

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