[Intel-gfx] [PATCH 1/3] drm/i915: Lift i915_vma_pin() out of intel_renderstate_emit()

Mika Kuoppala mika.kuoppala at linux.intel.com
Tue Dec 3 13:16:28 UTC 2019


Chris Wilson <chris at chris-wilson.co.uk> writes:

> Once inside a request, inside the timeline->mutex, pinning is verboten.
>
> <4> [896.032829] ======================================================
> <4> [896.032831] WARNING: possible circular locking dependency detected
> <4> [896.032835] 5.4.0-rc8-CI-Patchwork_15533+ #1 Tainted: G     U
> <4> [896.032838] ------------------------------------------------------
> <4> [896.032841] gem_exec_parall/3720 is trying to acquire lock:
> <4> [896.032844] ffff888401863270 (&kernel#2){+.+.}, at: i915_request_create+0x16/0x1c0 [i915]
> <4> [896.032915]
> but task is already holding lock:
> <4> [896.032917] ffff8883ec1c93c0 (&vm->mutex){+.+.}, at: i915_vma_pin+0xf3/0x11c0 [i915]
> <4> [896.032952]
> which lock already depends on the new lock.
>
> <4> [896.032954]
> the existing dependency chain (in reverse order) is:
> <4> [896.032956]
> -> #1 (&vm->mutex){+.+.}:
> <4> [896.032961]        __mutex_lock+0x9a/0x9d0
> <4> [896.032995]        i915_vma_pin+0xf3/0x11c0 [i915]
> <4> [896.033033]        intel_renderstate_emit+0xb9/0x9e0 [i915]
> <4> [896.033081]        i915_gem_init+0x5a9/0xa50 [i915]
> <4> [896.033112]        i915_driver_probe+0xb00/0x15f0 [i915]
> <4> [896.033144]        i915_pci_probe+0x43/0x1c0 [i915]
> <4> [896.033149]        pci_device_probe+0x9e/0x120
> <4> [896.033154]        really_probe+0xea/0x420
> <4> [896.033158]        driver_probe_device+0x10b/0x120
> <4> [896.033161]        device_driver_attach+0x4a/0x50
> <4> [896.033164]        __driver_attach+0x97/0x130
> <4> [896.033168]        bus_for_each_dev+0x74/0xc0
> <4> [896.033171]        bus_add_driver+0x142/0x220
> <4> [896.033174]        driver_register+0x56/0xf0
> <4> [896.033178]        do_one_initcall+0x58/0x2ff
> <4> [896.033183]        do_init_module+0x56/0x1f8
> <4> [896.033187]        load_module+0x243e/0x29f0
> <4> [896.033190]        __do_sys_finit_module+0xe9/0x110
> <4> [896.033194]        do_syscall_64+0x4f/0x210
> <4> [896.033197]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
> <4> [896.033200]
> -> #0 (&kernel#2){+.+.}:
> <4> [896.033206]        __lock_acquire+0x1328/0x15d0
> <4> [896.033209]        lock_acquire+0xa7/0x1c0
> <4> [896.033213]        __mutex_lock+0x9a/0x9d0
> <4> [896.033255]        i915_request_create+0x16/0x1c0 [i915]
> <4> [896.033287]        intel_engine_flush_barriers+0x4c/0x100 [i915]
> <4> [896.033327]        ggtt_flush+0x37/0x60 [i915]
> <4> [896.033366]        i915_gem_evict_something+0x46b/0x5a0 [i915]
> <4> [896.033407]        i915_gem_gtt_insert+0x21d/0x6a0 [i915]
> <4> [896.033449]        i915_vma_pin+0xb36/0x11c0 [i915]
> <4> [896.033488]        gen6_ppgtt_pin+0xd5/0x170 [i915]
> <4> [896.033523]        ring_context_pin+0x2e/0xc0 [i915]
> <4> [896.033554]        __intel_context_do_pin+0x6b/0x190 [i915]
> <4> [896.033591]        i915_gem_do_execbuffer+0x1814/0x26c0 [i915]
> <4> [896.033627]        i915_gem_execbuffer2_ioctl+0x11b/0x460 [i915]
> <4> [896.033632]        drm_ioctl_kernel+0xa7/0xf0
> <4> [896.033635]        drm_ioctl+0x2e1/0x390
> <4> [896.033638]        do_vfs_ioctl+0xa0/0x6f0
> <4> [896.033641]        ksys_ioctl+0x35/0x60
> <4> [896.033644]        __x64_sys_ioctl+0x11/0x20
> <4> [896.033647]        do_syscall_64+0x4f/0x210
> <4> [896.033650]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Lift the object allocation and pin prior to the request construction.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>

Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/gt/intel_renderstate.c | 97 ++++++++++++---------
>  drivers/gpu/drm/i915/gt/intel_renderstate.h | 17 +++-
>  drivers/gpu/drm/i915/i915_gem.c             |  8 +-
>  3 files changed, 78 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_renderstate.c b/drivers/gpu/drm/i915/gt/intel_renderstate.c
> index c4edc35e7d89..5954ecc3207f 100644
> --- a/drivers/gpu/drm/i915/gt/intel_renderstate.c
> +++ b/drivers/gpu/drm/i915/gt/intel_renderstate.c
> @@ -29,16 +29,6 @@
>  #include "intel_renderstate.h"
>  #include "intel_ring.h"
>  
> -struct intel_renderstate {
> -	const struct intel_renderstate_rodata *rodata;
> -	struct drm_i915_gem_object *obj;
> -	struct i915_vma *vma;
> -	u32 batch_offset;
> -	u32 batch_size;
> -	u32 aux_offset;
> -	u32 aux_size;
> -};
> -
>  static const struct intel_renderstate_rodata *
>  render_state_get_rodata(const struct intel_engine_cs *engine)
>  {
> @@ -84,11 +74,11 @@ static int render_state_setup(struct intel_renderstate *so,
>  	u32 *d;
>  	int ret;
>  
> -	ret = i915_gem_object_prepare_write(so->obj, &needs_clflush);
> +	ret = i915_gem_object_prepare_write(so->vma->obj, &needs_clflush);
>  	if (ret)
>  		return ret;
>  
> -	d = kmap_atomic(i915_gem_object_get_dirty_page(so->obj, 0));
> +	d = kmap_atomic(i915_gem_object_get_dirty_page(so->vma->obj, 0));
>  
>  	while (i < rodata->batch_items) {
>  		u32 s = rodata->batch[i];
> @@ -166,7 +156,7 @@ static int render_state_setup(struct intel_renderstate *so,
>  
>  	ret = 0;
>  out:
> -	i915_gem_object_finish_access(so->obj);
> +	i915_gem_object_finish_access(so->vma->obj);
>  	return ret;
>  
>  err:
> @@ -177,61 +167,84 @@ static int render_state_setup(struct intel_renderstate *so,
>  
>  #undef OUT_BATCH
>  
> -int intel_renderstate_emit(struct i915_request *rq)
> +int intel_renderstate_init(struct intel_renderstate *so,
> +			   struct intel_engine_cs *engine)
>  {
> -	struct intel_engine_cs *engine = rq->engine;
> -	struct intel_renderstate so = {}; /* keep the compiler happy */
> +	struct drm_i915_gem_object *obj;
>  	int err;
>  
> -	so.rodata = render_state_get_rodata(engine);
> -	if (!so.rodata)
> +	memset(so, 0, sizeof(*so));
> +
> +	so->rodata = render_state_get_rodata(engine);
> +	if (!so->rodata)
>  		return 0;
>  
> -	if (so.rodata->batch_items * 4 > PAGE_SIZE)
> +	if (so->rodata->batch_items * 4 > PAGE_SIZE)
>  		return -EINVAL;
>  
> -	so.obj = i915_gem_object_create_internal(engine->i915, PAGE_SIZE);
> -	if (IS_ERR(so.obj))
> -		return PTR_ERR(so.obj);
> +	obj = i915_gem_object_create_internal(engine->i915, PAGE_SIZE);
> +	if (IS_ERR(obj))
> +		return PTR_ERR(obj);
>  
> -	so.vma = i915_vma_instance(so.obj, &engine->gt->ggtt->vm, NULL);
> -	if (IS_ERR(so.vma)) {
> -		err = PTR_ERR(so.vma);
> +	so->vma = i915_vma_instance(obj, &engine->gt->ggtt->vm, NULL);
> +	if (IS_ERR(so->vma)) {
> +		err = PTR_ERR(so->vma);
>  		goto err_obj;
>  	}
>  
> -	err = i915_vma_pin(so.vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
> +	err = i915_vma_pin(so->vma, 0, 0, PIN_GLOBAL | PIN_HIGH);
>  	if (err)
>  		goto err_vma;
>  
> -	err = render_state_setup(&so, rq->i915);
> +	err = render_state_setup(so, engine->i915);
>  	if (err)
>  		goto err_unpin;
>  
> +	return 0;
> +
> +err_unpin:
> +	i915_vma_unpin(so->vma);
> +err_vma:
> +	i915_vma_close(so->vma);
> +err_obj:
> +	i915_gem_object_put(obj);
> +	so->vma = NULL;
> +	return err;
> +}
> +
> +int intel_renderstate_emit(struct intel_renderstate *so,
> +			   struct i915_request *rq)
> +{
> +	struct intel_engine_cs *engine = rq->engine;
> +	int err;
> +
> +	if (!so->vma)
> +		return 0;
> +
>  	err = engine->emit_bb_start(rq,
> -				    so.batch_offset, so.batch_size,
> +				    so->batch_offset, so->batch_size,
>  				    I915_DISPATCH_SECURE);
>  	if (err)
> -		goto err_unpin;
> +		return err;
>  
> -	if (so.aux_size > 8) {
> +	if (so->aux_size > 8) {
>  		err = engine->emit_bb_start(rq,
> -					    so.aux_offset, so.aux_size,
> +					    so->aux_offset, so->aux_size,
>  					    I915_DISPATCH_SECURE);
>  		if (err)
> -			goto err_unpin;
> +			return err;
>  	}
>  
> -	i915_vma_lock(so.vma);
> -	err = i915_request_await_object(rq, so.vma->obj, false);
> +	i915_vma_lock(so->vma);
> +	err = i915_request_await_object(rq, so->vma->obj, false);
>  	if (err == 0)
> -		err = i915_vma_move_to_active(so.vma, rq, 0);
> -	i915_vma_unlock(so.vma);
> -err_unpin:
> -	i915_vma_unpin(so.vma);
> -err_vma:
> -	i915_vma_close(so.vma);
> -err_obj:
> -	i915_gem_object_put(so.obj);
> +		err = i915_vma_move_to_active(so->vma, rq, 0);
> +	i915_vma_unlock(so->vma);
> +
>  	return err;
>  }
> +
> +void intel_renderstate_fini(struct intel_renderstate *so)
> +{
> +	i915_vma_unpin_and_release(&so->vma, 0);
> +}
> diff --git a/drivers/gpu/drm/i915/gt/intel_renderstate.h b/drivers/gpu/drm/i915/gt/intel_renderstate.h
> index 8d5079145054..5700be69a05a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_renderstate.h
> +++ b/drivers/gpu/drm/i915/gt/intel_renderstate.h
> @@ -27,6 +27,8 @@
>  #include <linux/types.h>
>  
>  struct i915_request;
> +struct intel_engine_cs;
> +struct i915_vma;
>  
>  struct intel_renderstate_rodata {
>  	const u32 *reloc;
> @@ -46,6 +48,19 @@ extern const struct intel_renderstate_rodata gen7_null_state;
>  extern const struct intel_renderstate_rodata gen8_null_state;
>  extern const struct intel_renderstate_rodata gen9_null_state;
>  
> -int intel_renderstate_emit(struct i915_request *rq);
> +struct intel_renderstate {
> +	const struct intel_renderstate_rodata *rodata;
> +	struct i915_vma *vma;
> +	u32 batch_offset;
> +	u32 batch_size;
> +	u32 aux_offset;
> +	u32 aux_size;
> +};
> +
> +int intel_renderstate_init(struct intel_renderstate *so,
> +			   struct intel_engine_cs *engine);
> +int intel_renderstate_emit(struct intel_renderstate *so,
> +			   struct i915_request *rq);
> +void intel_renderstate_fini(struct intel_renderstate *so);
>  
>  #endif /* _INTEL_RENDERSTATE_H_ */
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 61395b03443e..d2c2d66bb5f2 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1071,9 +1071,14 @@ static int __intel_engines_record_defaults(struct intel_gt *gt)
>  	 */
>  
>  	for_each_engine(engine, gt, id) {
> +		struct intel_renderstate so;
>  		struct intel_context *ce;
>  		struct i915_request *rq;
>  
> +		err = intel_renderstate_init(&so, engine);
> +		if (err)
> +			goto out;
> +
>  		/* We must be able to switch to something! */
>  		GEM_BUG_ON(!engine->kernel_context);
>  		engine->serial++; /* force the kernel context switch */
> @@ -1096,13 +1101,14 @@ static int __intel_engines_record_defaults(struct intel_gt *gt)
>  		if (err)
>  			goto err_rq;
>  
> -		err = intel_renderstate_emit(rq);
> +		err = intel_renderstate_emit(&so, rq);
>  		if (err)
>  			goto err_rq;
>  
>  err_rq:
>  		requests[id] = i915_request_get(rq);
>  		i915_request_add(rq);
> +		intel_renderstate_fini(&so);
>  		if (err)
>  			goto out;
>  	}
> -- 
> 2.24.0


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