[Intel-gfx] [PATCH v2 4/7] drm/i915/gtt/dgfx: place the PD in LMEM

[Tang, CQ]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Matthew Auld
> Sent: Tuesday, April 27, 2021 1:54 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v2 4/7] drm/i915/gtt/dgfx: place the PD in LMEM
> 
> It's a requirement that for dgfx we place all the paging structures in device
> local-memory.
> 
> v2: use i915_coherent_map_type()
> v3: improve the shared dma-resv object comment
> 
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gt/gen8_ppgtt.c |  5 ++++-
> drivers/gpu/drm/i915/gt/intel_gtt.c  | 30 +++++++++++++++++++++++++---
> drivers/gpu/drm/i915/gt/intel_gtt.h  |  1 +
>  3 files changed, 32 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> index f83496836f0f..11fb5df45a0f 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> @@ -712,7 +712,10 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt
> *gt)
>  	 */
>  	ppgtt->vm.has_read_only = !IS_GEN_RANGE(gt->i915, 11, 12);
> 
> -	ppgtt->vm.alloc_pt_dma = alloc_pt_dma;
> +	if (HAS_LMEM(gt->i915))
> +		ppgtt->vm.alloc_pt_dma = alloc_pt_lmem;

Here we might want to allocate lmem from the 'gt' in the argument,  however, below inside alloc_pt_lmem(), we always allocate lmem to tile0.
Is this desired?

--CQ

> +	else
> +		ppgtt->vm.alloc_pt_dma = alloc_pt_dma;
> 
>  	err = gen8_init_scratch(&ppgtt->vm);
>  	if (err)
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c
> b/drivers/gpu/drm/i915/gt/intel_gtt.c
> index d386b89e2758..061c39d2ad51 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
> @@ -7,10 +7,26 @@
> 
>  #include <linux/fault-inject.h>
> 
> +#include "gem/i915_gem_lmem.h"
>  #include "i915_trace.h"
>  #include "intel_gt.h"
>  #include "intel_gtt.h"
> 
> +struct drm_i915_gem_object *alloc_pt_lmem(struct i915_address_space
> +*vm, int sz) {
> +	struct drm_i915_gem_object *obj;
> +
> +	obj = i915_gem_object_create_lmem(vm->i915, sz, 0);
> +	/*
> +	 * Ensure all paging structures for this vm share the same dma-resv
> +	 * object underneath, with the idea that one object_lock() will lock
> +	 * them all at once.
> +	 */
> +	if (!IS_ERR(obj))
> +		obj->base.resv = &vm->resv;
> +	return obj;
> +}
> +
>  struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm,
> int sz)  {
>  	struct drm_i915_gem_object *obj;
> @@ -19,7 +35,11 @@ struct drm_i915_gem_object *alloc_pt_dma(struct
> i915_address_space *vm, int sz)
>  		i915_gem_shrink_all(vm->i915);
> 
>  	obj = i915_gem_object_create_internal(vm->i915, sz);
> -	/* ensure all dma objects have the same reservation class */
> +	/*
> +	 * Ensure all paging structures for this vm share the same dma-resv
> +	 * object underneath, with the idea that one object_lock() will lock
> +	 * them all at once.
> +	 */
>  	if (!IS_ERR(obj))
>  		obj->base.resv = &vm->resv;
>  	return obj;
> @@ -27,9 +47,11 @@ struct drm_i915_gem_object *alloc_pt_dma(struct
> i915_address_space *vm, int sz)
> 
>  int map_pt_dma(struct i915_address_space *vm, struct
> drm_i915_gem_object *obj)  {
> +	enum i915_map_type type;
>  	void *vaddr;
> 
> -	vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
> +	type = i915_coherent_map_type(vm->i915, obj, true);
> +	vaddr = i915_gem_object_pin_map_unlocked(obj, type);
>  	if (IS_ERR(vaddr))
>  		return PTR_ERR(vaddr);
> 
> @@ -39,9 +61,11 @@ int map_pt_dma(struct i915_address_space *vm,
> struct drm_i915_gem_object *obj)
> 
>  int map_pt_dma_locked(struct i915_address_space *vm, struct
> drm_i915_gem_object *obj)  {
> +	enum i915_map_type type;
>  	void *vaddr;
> 
> -	vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
> +	type = i915_coherent_map_type(vm->i915, obj, true);
> +	vaddr = i915_gem_object_pin_map(obj, type);
>  	if (IS_ERR(vaddr))
>  		return PTR_ERR(vaddr);
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h
> b/drivers/gpu/drm/i915/gt/intel_gtt.h
> index 40e486704558..44ce27c51631 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> @@ -527,6 +527,7 @@ int setup_scratch_page(struct i915_address_space
> *vm);  void free_scratch(struct i915_address_space *vm);
> 
>  struct drm_i915_gem_object *alloc_pt_dma(struct i915_address_space *vm,
> int sz);
> +struct drm_i915_gem_object *alloc_pt_lmem(struct i915_address_space
> +*vm, int sz);
>  struct i915_page_table *alloc_pt(struct i915_address_space *vm);  struct
> i915_page_directory *alloc_pd(struct i915_address_space *vm);  struct
> i915_page_directory *__alloc_pd(int npde);
> --
> 2.26.3
> 
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