Commit 3f43c876 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Move GEM object busy checking to its own file 



Continuing the decluttering of i915_gem.c by moving the object busy
checking into its own file.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528092956.14910-12-chris@chris-wilson.co.uk
parent d45a1a53

drivers/gpu/drm/i915/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ i915-y += $(gt-y) 
# GEM (Graphics Execution Management) code

obj-y += gem/

gem-y += \

	gem/i915_gem_busy.o \

	gem/i915_gem_clflush.o \

	gem/i915_gem_context.o \

	gem/i915_gem_dmabuf.o \

drivers/gpu/drm/i915/gem/i915_gem_busy.c

0 → 100644
+138 −0
Original line number Diff line number Diff line 
/*

 * SPDX-License-Identifier: MIT

 *

 * Copyright © 2014-2016 Intel Corporation

 */



#include "gt/intel_engine.h"



#include "i915_gem_ioctls.h"

#include "i915_gem_object.h"



static __always_inline u32 __busy_read_flag(u8 id)

{

	if (id == (u8)I915_ENGINE_CLASS_INVALID)

		return 0xffff0000u;



	GEM_BUG_ON(id >= 16);

	return 0x10000u << id;

}



static __always_inline u32 __busy_write_id(u8 id)

{

	/*

	 * The uABI guarantees an active writer is also amongst the read

	 * engines. This would be true if we accessed the activity tracking

	 * under the lock, but as we perform the lookup of the object and

	 * its activity locklessly we can not guarantee that the last_write

	 * being active implies that we have set the same engine flag from

	 * last_read - hence we always set both read and write busy for

	 * last_write.

	 */

	if (id == (u8)I915_ENGINE_CLASS_INVALID)

		return 0xffffffffu;



	return (id + 1) | __busy_read_flag(id);

}



static __always_inline unsigned int

__busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u8 id))

{

	const struct i915_request *rq;



	/*

	 * We have to check the current hw status of the fence as the uABI

	 * guarantees forward progress. We could rely on the idle worker

	 * to eventually flush us, but to minimise latency just ask the

	 * hardware.

	 *

	 * Note we only report on the status of native fences.

	 */

	if (!dma_fence_is_i915(fence))

		return 0;



	/* opencode to_request() in order to avoid const warnings */

	rq = container_of(fence, const struct i915_request, fence);

	if (i915_request_completed(rq))

		return 0;



	/* Beware type-expansion follies! */

	BUILD_BUG_ON(!typecheck(u8, rq->engine->uabi_class));

	return flag(rq->engine->uabi_class);

}



static __always_inline unsigned int

busy_check_reader(const struct dma_fence *fence)

{

	return __busy_set_if_active(fence, __busy_read_flag);

}



static __always_inline unsigned int

busy_check_writer(const struct dma_fence *fence)

{

	if (!fence)

		return 0;



	return __busy_set_if_active(fence, __busy_write_id);

}



int

i915_gem_busy_ioctl(struct drm_device *dev, void *data,

		    struct drm_file *file)

{

	struct drm_i915_gem_busy *args = data;

	struct drm_i915_gem_object *obj;

	struct reservation_object_list *list;

	unsigned int seq;

	int err;



	err = -ENOENT;

	rcu_read_lock();

	obj = i915_gem_object_lookup_rcu(file, args->handle);

	if (!obj)

		goto out;



	/*

	 * A discrepancy here is that we do not report the status of

	 * non-i915 fences, i.e. even though we may report the object as idle,

	 * a call to set-domain may still stall waiting for foreign rendering.

	 * This also means that wait-ioctl may report an object as busy,

	 * where busy-ioctl considers it idle.

	 *

	 * We trade the ability to warn of foreign fences to report on which

	 * i915 engines are active for the object.

	 *

	 * Alternatively, we can trade that extra information on read/write

	 * activity with

	 *	args->busy =

	 *		!reservation_object_test_signaled_rcu(obj->resv, true);

	 * to report the overall busyness. This is what the wait-ioctl does.

	 *

	 */

retry:

	seq = raw_read_seqcount(&obj->resv->seq);



	/* Translate the exclusive fence to the READ *and* WRITE engine */

	args->busy = busy_check_writer(rcu_dereference(obj->resv->fence_excl));



	/* Translate shared fences to READ set of engines */

	list = rcu_dereference(obj->resv->fence);

	if (list) {

		unsigned int shared_count = list->shared_count, i;



		for (i = 0; i < shared_count; ++i) {

			struct dma_fence *fence =

				rcu_dereference(list->shared[i]);



			args->busy |= busy_check_reader(fence);

		}

	}



	if (args->busy && read_seqcount_retry(&obj->resv->seq, seq))

		goto retry;



	err = 0;

out:

	rcu_read_unlock();

	return err;

}

drivers/gpu/drm/i915/i915_gem.c

+0 −128
Original line number Diff line number Diff line
@@ -1142,134 +1142,6 @@ i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, 
	return vma;

}



static __always_inline u32 __busy_read_flag(u8 id)

{

	if (id == (u8)I915_ENGINE_CLASS_INVALID)

		return 0xffff0000u;



	GEM_BUG_ON(id >= 16);

	return 0x10000u << id;

}



static __always_inline u32 __busy_write_id(u8 id)

{

	/*

	 * The uABI guarantees an active writer is also amongst the read

	 * engines. This would be true if we accessed the activity tracking

	 * under the lock, but as we perform the lookup of the object and

	 * its activity locklessly we can not guarantee that the last_write

	 * being active implies that we have set the same engine flag from

	 * last_read - hence we always set both read and write busy for

	 * last_write.

	 */

	if (id == (u8)I915_ENGINE_CLASS_INVALID)

		return 0xffffffffu;



	return (id + 1) | __busy_read_flag(id);

}



static __always_inline unsigned int

__busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u8 id))

{

	const struct i915_request *rq;



	/*

	 * We have to check the current hw status of the fence as the uABI

	 * guarantees forward progress. We could rely on the idle worker

	 * to eventually flush us, but to minimise latency just ask the

	 * hardware.

	 *

	 * Note we only report on the status of native fences.

	 */

	if (!dma_fence_is_i915(fence))

		return 0;



	/* opencode to_request() in order to avoid const warnings */

	rq = container_of(fence, const struct i915_request, fence);

	if (i915_request_completed(rq))

		return 0;



	/* Beware type-expansion follies! */

	BUILD_BUG_ON(!typecheck(u8, rq->engine->uabi_class));

	return flag(rq->engine->uabi_class);

}



static __always_inline unsigned int

busy_check_reader(const struct dma_fence *fence)

{

	return __busy_set_if_active(fence, __busy_read_flag);

}



static __always_inline unsigned int

busy_check_writer(const struct dma_fence *fence)

{

	if (!fence)

		return 0;



	return __busy_set_if_active(fence, __busy_write_id);

}



int

i915_gem_busy_ioctl(struct drm_device *dev, void *data,

		    struct drm_file *file)

{

	struct drm_i915_gem_busy *args = data;

	struct drm_i915_gem_object *obj;

	struct reservation_object_list *list;

	unsigned int seq;

	int err;



	err = -ENOENT;

	rcu_read_lock();

	obj = i915_gem_object_lookup_rcu(file, args->handle);

	if (!obj)

		goto out;



	/*

	 * A discrepancy here is that we do not report the status of

	 * non-i915 fences, i.e. even though we may report the object as idle,

	 * a call to set-domain may still stall waiting for foreign rendering.

	 * This also means that wait-ioctl may report an object as busy,

	 * where busy-ioctl considers it idle.

	 *

	 * We trade the ability to warn of foreign fences to report on which

	 * i915 engines are active for the object.

	 *

	 * Alternatively, we can trade that extra information on read/write

	 * activity with

	 *	args->busy =

	 *		!reservation_object_test_signaled_rcu(obj->resv, true);

	 * to report the overall busyness. This is what the wait-ioctl does.

	 *

	 */

retry:

	seq = raw_read_seqcount(&obj->resv->seq);



	/* Translate the exclusive fence to the READ *and* WRITE engine */

	args->busy = busy_check_writer(rcu_dereference(obj->resv->fence_excl));



	/* Translate shared fences to READ set of engines */

	list = rcu_dereference(obj->resv->fence);

	if (list) {

		unsigned int shared_count = list->shared_count, i;



		for (i = 0; i < shared_count; ++i) {

			struct dma_fence *fence =

				rcu_dereference(list->shared[i]);



			args->busy |= busy_check_reader(fence);

		}

	}



	if (args->busy && read_seqcount_retry(&obj->resv->seq, seq))

		goto retry;



	err = 0;

out:

	rcu_read_unlock();

	return err;

}



int

i915_gem_throttle_ioctl(struct drm_device *dev, void *data,

			struct drm_file *file_priv)

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