Michał Winiarski <michal.winiarski@xxxxxxxxx> writes:
> Let's use more top-down approach, where each gen8_ppgtt_clear_* function
> is responsible for clearing the struct passed as an argument and calling
> relevant clear_range functions on lower-level tables.
> Doing this rather than operating on PTE ranges makes the implementation
> of shrinking page tables quite simple.
>
> v2: Drop min when calculating num_entries, no negation in 48b ppgtt
> check, no newlines in vars block (Joonas)
>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> Cc: Michel Thierry <michel.thierry@xxxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx>
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_gem_gtt.c | 107 +++++++++++++++++++-----------------
> 1 file changed, 58 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 08e2f35..adabf58 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -704,59 +704,78 @@ static int gen8_48b_mm_switch(struct i915_hw_ppgtt *ppgtt,
> return gen8_write_pdp(req, 0, px_dma(&ppgtt->pml4));
> }
>
> -static void gen8_ppgtt_clear_pte_range(struct i915_address_space *vm,
> - struct i915_page_directory_pointer *pdp,
> - uint64_t start,
> - uint64_t length,
> - gen8_pte_t scratch_pte)
> +static void gen8_ppgtt_clear_pt(struct i915_address_space *vm,
> + struct i915_page_table *pt,
> + uint64_t start,
> + uint64_t length)
> {
> struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
> +
> + unsigned int pte_start = gen8_pte_index(start);
> + unsigned int num_entries = gen8_pte_count(start, length);
> + uint64_t pte;
> gen8_pte_t *pt_vaddr;
> - unsigned pdpe = gen8_pdpe_index(start);
> - unsigned pde = gen8_pde_index(start);
> - unsigned pte = gen8_pte_index(start);
> - unsigned num_entries = length >> PAGE_SHIFT;
> - unsigned last_pte, i;
> + gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
> + I915_CACHE_LLC);
>
> - if (WARN_ON(!pdp))
> + if (WARN_ON(!px_page(pt)))
> return;
>
> - while (num_entries) {
> - struct i915_page_directory *pd;
> - struct i915_page_table *pt;
> + bitmap_clear(pt->used_ptes, pte_start, num_entries);
>
> - if (WARN_ON(!pdp->page_directory[pdpe]))
> - break;
> + pt_vaddr = kmap_px(pt);
> +
> + for (pte = pte_start; pte < num_entries; pte++)
> + pt_vaddr[pte] = scratch_pte;
>
> - pd = pdp->page_directory[pdpe];
> + kunmap_px(ppgtt, pt_vaddr);
> +}
> +
> +static void gen8_ppgtt_clear_pd(struct i915_address_space *vm,
> + struct i915_page_directory *pd,
> + uint64_t start,
> + uint64_t length)
> +{
> + struct i915_page_table *pt;
> + uint64_t pde;
>
> + gen8_for_each_pde(pt, pd, start, length, pde) {
> if (WARN_ON(!pd->page_table[pde]))
> break;
>
> - pt = pd->page_table[pde];
> + gen8_ppgtt_clear_pt(vm, pt, start, length);
> + }
> +}
>
> - if (WARN_ON(!px_page(pt)))
> - break;
> +static void gen8_ppgtt_clear_pdp(struct i915_address_space *vm,
> + struct i915_page_directory_pointer *pdp,
> + uint64_t start,
> + uint64_t length)
> +{
> + struct i915_page_directory *pd;
> + uint64_t pdpe;
>
> - last_pte = pte + num_entries;
> - if (last_pte > GEN8_PTES)
> - last_pte = GEN8_PTES;
> + gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
> + if (WARN_ON(!pdp->page_directory[pdpe]))
> + break;
>
> - pt_vaddr = kmap_px(pt);
> + gen8_ppgtt_clear_pd(vm, pd, start, length);
> + }
> +}
>
> - for (i = pte; i < last_pte; i++) {
> - pt_vaddr[i] = scratch_pte;
> - num_entries--;
> - }
> +static void gen8_ppgtt_clear_pml4(struct i915_address_space *vm,
> + struct i915_pml4 *pml4,
> + uint64_t start,
> + uint64_t length)
> +{
> + struct i915_page_directory_pointer *pdp;
> + uint64_t pml4e;
>
> - kunmap_px(ppgtt, pt_vaddr);
> + gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
> + if (WARN_ON(!pml4->pdps[pml4e]))
> + break;
>
> - pte = 0;
> - if (++pde == I915_PDES) {
> - if (++pdpe == I915_PDPES_PER_PDP(vm->dev))
> - break;
> - pde = 0;
> - }
> + gen8_ppgtt_clear_pdp(vm, pdp, start, length);
> }
> }
>
> @@ -764,21 +783,11 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
> uint64_t start, uint64_t length)
> {
> struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
> - gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
> - I915_CACHE_LLC);
>
> - if (!USES_FULL_48BIT_PPGTT(vm->dev)) {
> - gen8_ppgtt_clear_pte_range(vm, &ppgtt->pdp, start, length,
> - scratch_pte);
> - } else {
> - uint64_t pml4e;
> - struct i915_page_directory_pointer *pdp;
> -
> - gen8_for_each_pml4e(pdp, &ppgtt->pml4, start, length, pml4e) {
> - gen8_ppgtt_clear_pte_range(vm, pdp, start, length,
> - scratch_pte);
> - }
> - }
> + if (USES_FULL_48BIT_PPGTT(vm->dev))
> + gen8_ppgtt_clear_pml4(vm, &ppgtt->pml4, start, length);
> + else
> + gen8_ppgtt_clear_pdp(vm, &ppgtt->pdp, start, length);
> }
>
> static void
> --
> 2.7.4
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