Commit 986dbac4 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gtt: Cache the PTE encoding of the scratch page 



As the most frequent PTE encoding is for the scratch page, cache it upon
creation.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: default avatarMatthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180614184218.1606-1-chris@chris-wilson.co.uk
parent 4a192c7e

drivers/gpu/drm/i915/i915_gem_gtt.c

+10 −10
Original line number Diff line number Diff line
@@ -640,11 +640,10 @@ static void gen8_initialize_pt(struct i915_address_space *vm, 
		gen8_pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC));

}



static void gen6_initialize_pt(struct i915_address_space *vm,

static void gen6_initialize_pt(struct gen6_hw_ppgtt *ppgtt,

			       struct i915_page_table *pt)

{

	fill32_px(vm, pt,

		  vm->pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC, 0));

	fill32_px(&ppgtt->base.vm, pt, ppgtt->scratch_pte);

}



static struct i915_page_directory *alloc_pd(struct i915_address_space *vm)
@@ -1631,9 +1630,7 @@ err_free: 
static void gen6_dump_ppgtt(struct i915_hw_ppgtt *base, struct seq_file *m)

{

	struct gen6_hw_ppgtt *ppgtt = to_gen6_ppgtt(base);

	struct i915_address_space *vm = &base->vm;

	const gen6_pte_t scratch_pte =

		vm->pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC, 0);

	const gen6_pte_t scratch_pte = ppgtt->scratch_pte;

	struct i915_page_table *pt;

	u32 pte, pde;
@@ -1758,8 +1755,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm, 
	unsigned int pde = first_entry / GEN6_PTES;

	unsigned int pte = first_entry % GEN6_PTES;

	unsigned int num_entries = length >> PAGE_SHIFT;

	const gen6_pte_t scratch_pte =

		vm->pte_encode(vm->scratch_page.daddr, I915_CACHE_LLC, 0);

	const gen6_pte_t scratch_pte = ppgtt->scratch_pte;



	while (num_entries) {

		struct i915_page_table *pt = ppgtt->base.pd.page_table[pde++];
@@ -1850,7 +1846,7 @@ static int gen6_alloc_va_range(struct i915_address_space *vm, 
			if (IS_ERR(pt))

				goto unwind_out;



			gen6_initialize_pt(vm, pt);

			gen6_initialize_pt(ppgtt, pt);

			ppgtt->base.pd.page_table[pde] = pt;



			if (i915_vma_is_bound(ppgtt->vma,
@@ -1888,13 +1884,17 @@ static int gen6_ppgtt_init_scratch(struct gen6_hw_ppgtt *ppgtt) 
	if (ret)

		return ret;



	ppgtt->scratch_pte =

		vm->pte_encode(vm->scratch_page.daddr,

			       I915_CACHE_NONE, PTE_READ_ONLY);



	vm->scratch_pt = alloc_pt(vm);

	if (IS_ERR(vm->scratch_pt)) {

		cleanup_scratch_page(vm);

		return PTR_ERR(vm->scratch_pt);

	}



	gen6_initialize_pt(vm, vm->scratch_pt);

	gen6_initialize_pt(ppgtt, vm->scratch_pt);

	gen6_for_all_pdes(unused, &ppgtt->base.pd, pde)

		ppgtt->base.pd.page_table[pde] = vm->scratch_pt;

drivers/gpu/drm/i915/i915_gem_gtt.h

+1 −0
Original line number Diff line number Diff line
@@ -412,6 +412,7 @@ struct gen6_hw_ppgtt { 


	struct i915_vma *vma;

	gen6_pte_t __iomem *pd_addr;

	gen6_pte_t scratch_pte;



	unsigned int pin_count;

	bool scan_for_unused_pt;

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