[Intel-gfx] [PATCH v6 02/19] drm/i915/gen8: Make pdp allocation more dynamic

Daniel Vetter daniel at ffwll.ch
Wed Aug 5 08:31:11 PDT 2015


On Wed, Jul 29, 2015 at 05:23:46PM +0100, Michel Thierry wrote:
> This transitional patch doesn't do much for the existing code. However,
> it should make upcoming patches to use the full 48b address space a bit
> easier.

commit message should also mention how exactly it's more dynamic and why
exactly that's useful ... It's ofc possible to infer that from the
context, but that won't be the case any more if you look at the patch
alone (with git blame or after a bisect). Please follow up with a few
words so I can add them to the commit message.
-Daniel

> 
> v2: Renamed  pdp_free to be similar to  pd/pt (unmap_and_free_pdp).
> v3: To facilitate testing, 48b mode will be available on Broadwell and
> GEN9+, when i915.enable_ppgtt = 3.
> v4: Rebase after s/page_tables/page_table/, added extra information
> about 4-level page table formats and use IS_ENABLED macro.
> v5: Check CONFIG_X86_64 instead of CONFIG_64BIT.
> v6: Rebase after Mika's ppgtt cleanup / scratch merge patch series, and
> follow
> his nomenclature in pdp functions (there is no alloc_pdp yet).
> v7: Rebase after merged version of Mika's ppgtt cleanup patch series.
> v8: Rebase after final merged version of Mika's ppgtt/scratch patches.
> v9: Introduce PML4 (and 48-bit checks) until next patch (Akash).
> v10: Also use test_bit to detect when pd/pt are already allocated (Akash)
> 
> Cc: Akash Goel <akash.goel at intel.com>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com> (v2+)
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 86 +++++++++++++++++++++++++++++--------
>  drivers/gpu/drm/i915/i915_gem_gtt.h | 17 +++++---
>  2 files changed, 80 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 189572d..28f3227 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -522,6 +522,43 @@ static void gen8_initialize_pd(struct i915_address_space *vm,
>  	fill_px(vm->dev, pd, scratch_pde);
>  }
>  
> +static int __pdp_init(struct drm_device *dev,
> +		      struct i915_page_directory_pointer *pdp)
> +{
> +	size_t pdpes = I915_PDPES_PER_PDP(dev);
> +
> +	pdp->used_pdpes = kcalloc(BITS_TO_LONGS(pdpes),
> +				  sizeof(unsigned long),
> +				  GFP_KERNEL);
> +	if (!pdp->used_pdpes)
> +		return -ENOMEM;
> +
> +	pdp->page_directory = kcalloc(pdpes, sizeof(*pdp->page_directory),
> +				      GFP_KERNEL);
> +	if (!pdp->page_directory) {
> +		kfree(pdp->used_pdpes);
> +		/* the PDP might be the statically allocated top level. Keep it
> +		 * as clean as possible */
> +		pdp->used_pdpes = NULL;
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +
> +static void __pdp_fini(struct i915_page_directory_pointer *pdp)
> +{
> +	kfree(pdp->used_pdpes);
> +	kfree(pdp->page_directory);
> +	pdp->page_directory = NULL;
> +}
> +
> +static void free_pdp(struct drm_device *dev,
> +		     struct i915_page_directory_pointer *pdp)
> +{
> +	__pdp_fini(pdp);
> +}
> +
>  /* Broadwell Page Directory Pointer Descriptors */
>  static int gen8_write_pdp(struct drm_i915_gem_request *req,
>  			  unsigned entry,
> @@ -720,7 +757,8 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
>  		container_of(vm, struct i915_hw_ppgtt, base);
>  	int i;
>  
> -	for_each_set_bit(i, ppgtt->pdp.used_pdpes, GEN8_LEGACY_PDPES) {
> +	for_each_set_bit(i, ppgtt->pdp.used_pdpes,
> +			 I915_PDPES_PER_PDP(ppgtt->base.dev)) {
>  		if (WARN_ON(!ppgtt->pdp.page_directory[i]))
>  			continue;
>  
> @@ -729,6 +767,7 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
>  		free_pd(ppgtt->base.dev, ppgtt->pdp.page_directory[i]);
>  	}
>  
> +	free_pdp(ppgtt->base.dev, &ppgtt->pdp);
>  	gen8_free_scratch(vm);
>  }
>  
> @@ -763,7 +802,7 @@ static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
>  
>  	gen8_for_each_pde(pt, pd, start, length, temp, pde) {
>  		/* Don't reallocate page tables */
> -		if (pt) {
> +		if (test_bit(pde, pd->used_pdes)) {
>  			/* Scratch is never allocated this way */
>  			WARN_ON(pt == ppgtt->base.scratch_pt);
>  			continue;
> @@ -820,11 +859,12 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
>  	struct i915_page_directory *pd;
>  	uint64_t temp;
>  	uint32_t pdpe;
> +	uint32_t pdpes = I915_PDPES_PER_PDP(dev);
>  
> -	WARN_ON(!bitmap_empty(new_pds, GEN8_LEGACY_PDPES));
> +	WARN_ON(!bitmap_empty(new_pds, pdpes));
>  
>  	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
> -		if (pd)
> +		if (test_bit(pdpe, pdp->used_pdpes))
>  			continue;
>  
>  		pd = alloc_pd(dev);
> @@ -839,18 +879,19 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
>  	return 0;
>  
>  unwind_out:
> -	for_each_set_bit(pdpe, new_pds, GEN8_LEGACY_PDPES)
> +	for_each_set_bit(pdpe, new_pds, pdpes)
>  		free_pd(dev, pdp->page_directory[pdpe]);
>  
>  	return -ENOMEM;
>  }
>  
>  static void
> -free_gen8_temp_bitmaps(unsigned long *new_pds, unsigned long **new_pts)
> +free_gen8_temp_bitmaps(unsigned long *new_pds, unsigned long **new_pts,
> +		       uint32_t pdpes)
>  {
>  	int i;
>  
> -	for (i = 0; i < GEN8_LEGACY_PDPES; i++)
> +	for (i = 0; i < pdpes; i++)
>  		kfree(new_pts[i]);
>  	kfree(new_pts);
>  	kfree(new_pds);
> @@ -861,23 +902,24 @@ free_gen8_temp_bitmaps(unsigned long *new_pds, unsigned long **new_pts)
>   */
>  static
>  int __must_check alloc_gen8_temp_bitmaps(unsigned long **new_pds,
> -					 unsigned long ***new_pts)
> +					 unsigned long ***new_pts,
> +					 uint32_t pdpes)
>  {
>  	int i;
>  	unsigned long *pds;
>  	unsigned long **pts;
>  
> -	pds = kcalloc(BITS_TO_LONGS(GEN8_LEGACY_PDPES), sizeof(unsigned long), GFP_KERNEL);
> +	pds = kcalloc(BITS_TO_LONGS(pdpes), sizeof(unsigned long), GFP_KERNEL);
>  	if (!pds)
>  		return -ENOMEM;
>  
> -	pts = kcalloc(GEN8_LEGACY_PDPES, sizeof(unsigned long *), GFP_KERNEL);
> +	pts = kcalloc(pdpes, sizeof(unsigned long *), GFP_KERNEL);
>  	if (!pts) {
>  		kfree(pds);
>  		return -ENOMEM;
>  	}
>  
> -	for (i = 0; i < GEN8_LEGACY_PDPES; i++) {
> +	for (i = 0; i < pdpes; i++) {
>  		pts[i] = kcalloc(BITS_TO_LONGS(I915_PDES),
>  				 sizeof(unsigned long), GFP_KERNEL);
>  		if (!pts[i])
> @@ -890,7 +932,7 @@ int __must_check alloc_gen8_temp_bitmaps(unsigned long **new_pds,
>  	return 0;
>  
>  err_out:
> -	free_gen8_temp_bitmaps(pds, pts);
> +	free_gen8_temp_bitmaps(pds, pts, pdpes);
>  	return -ENOMEM;
>  }
>  
> @@ -916,6 +958,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>  	const uint64_t orig_length = length;
>  	uint64_t temp;
>  	uint32_t pdpe;
> +	uint32_t pdpes = I915_PDPES_PER_PDP(ppgtt->base.dev);
>  	int ret;
>  
>  	/* Wrap is never okay since we can only represent 48b, and we don't
> @@ -927,7 +970,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>  	if (WARN_ON(start + length > ppgtt->base.total))
>  		return -ENODEV;
>  
> -	ret = alloc_gen8_temp_bitmaps(&new_page_dirs, &new_page_tables);
> +	ret = alloc_gen8_temp_bitmaps(&new_page_dirs, &new_page_tables, pdpes);
>  	if (ret)
>  		return ret;
>  
> @@ -935,7 +978,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>  	ret = gen8_ppgtt_alloc_page_directories(ppgtt, &ppgtt->pdp, start, length,
>  					new_page_dirs);
>  	if (ret) {
> -		free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);
> +		free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
>  		return ret;
>  	}
>  
> @@ -989,7 +1032,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
>  		__set_bit(pdpe, ppgtt->pdp.used_pdpes);
>  	}
>  
> -	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);
> +	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
>  	mark_tlbs_dirty(ppgtt);
>  	return 0;
>  
> @@ -999,10 +1042,10 @@ err_out:
>  			free_pt(vm->dev, ppgtt->pdp.page_directory[pdpe]->page_table[temp]);
>  	}
>  
> -	for_each_set_bit(pdpe, new_page_dirs, GEN8_LEGACY_PDPES)
> +	for_each_set_bit(pdpe, new_page_dirs, pdpes)
>  		free_pd(vm->dev, ppgtt->pdp.page_directory[pdpe]);
>  
> -	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);
> +	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
>  	mark_tlbs_dirty(ppgtt);
>  	return ret;
>  }
> @@ -1040,7 +1083,16 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
>  
>  	ppgtt->switch_mm = gen8_mm_switch;
>  
> +	ret = __pdp_init(false, &ppgtt->pdp);
> +
> +	if (ret)
> +		goto free_scratch;
> +
>  	return 0;
> +
> +free_scratch:
> +	gen8_free_scratch(&ppgtt->base);
> +	return ret;
>  }
>  
>  static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index d5bf953..87e389c 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -98,6 +98,9 @@ typedef uint64_t gen8_pde_t;
>  #define GEN8_LEGACY_PDPES		4
>  #define GEN8_PTES			I915_PTES(sizeof(gen8_pte_t))
>  
> +/* FIXME: Next patch will use dev */
> +#define I915_PDPES_PER_PDP(dev)		GEN8_LEGACY_PDPES
> +
>  #define PPAT_UNCACHED_INDEX		(_PAGE_PWT | _PAGE_PCD)
>  #define PPAT_CACHED_PDE_INDEX		0 /* WB LLC */
>  #define PPAT_CACHED_INDEX		_PAGE_PAT /* WB LLCeLLC */
> @@ -241,9 +244,10 @@ struct i915_page_directory {
>  };
>  
>  struct i915_page_directory_pointer {
> -	/* struct page *page; */
> -	DECLARE_BITMAP(used_pdpes, GEN8_LEGACY_PDPES);
> -	struct i915_page_directory *page_directory[GEN8_LEGACY_PDPES];
> +	struct i915_page_dma base;
> +
> +	unsigned long *used_pdpes;
> +	struct i915_page_directory **page_directory;
>  };
>  
>  struct i915_address_space {
> @@ -436,9 +440,10 @@ static inline uint32_t gen6_pde_index(uint32_t addr)
>  	     temp = min(temp, length),					\
>  	     start += temp, length -= temp)
>  
> -#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter)		\
> -	for (iter = gen8_pdpe_index(start);	\
> -	     pd = (pdp)->page_directory[iter], length > 0 && iter < GEN8_LEGACY_PDPES;	\
> +#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter)	\
> +	for (iter = gen8_pdpe_index(start); \
> +	     pd = (pdp)->page_directory[iter], \
> +	     length > 0 && (iter < I915_PDPES_PER_PDP(dev)); \
>  	     iter++,				\
>  	     temp = ALIGN(start+1, 1 << GEN8_PDPE_SHIFT) - start,	\
>  	     temp = min(temp, length),					\
> -- 
> 2.4.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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