[Intel-gfx] [PATCH v4 05/24] drm/i915: page table abstractions
Mika Kuoppala
mika.kuoppala at linux.intel.com
Wed Feb 18 03:27:14 PST 2015
Michel Thierry <michel.thierry at intel.com> writes:
> From: Ben Widawsky <benjamin.widawsky at intel.com>
>
> When we move to dynamic page allocation, keeping page_directory and pagetabs as
> separate structures will help to break actions into simpler tasks.
>
> To help transition the code nicely there is some wasted space in gen6/7.
> This will be ameliorated shortly.
>
> Following the x86 pagetable terminology:
> PDPE = struct i915_page_directory_pointer_entry.
> PDE = struct i915_page_directory_entry [page_directory].
> PTE = struct i915_page_table_entry [page_tables].
>
> v2: fixed mismatches after clean-up/rebase.
>
> v3: Clarify the names of the multiple levels of page tables (Daniel)
>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com> (v2, v3)
> ---
> drivers/gpu/drm/i915/i915_gem_gtt.c | 177 ++++++++++++++++++------------------
> drivers/gpu/drm/i915/i915_gem_gtt.h | 23 ++++-
> 2 files changed, 107 insertions(+), 93 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index b48b586..98b4698 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -334,7 +334,8 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
> I915_CACHE_LLC, use_scratch);
>
> while (num_entries) {
> - struct page *page_table = ppgtt->gen8_pt_pages[pdpe][pde];
> + struct i915_page_directory_entry *pd = &ppgtt->pdp.page_directory[pdpe];
> + struct page *page_table = pd->page_tables[pde].page;
>
> last_pte = pte + num_entries;
> if (last_pte > GEN8_PTES_PER_PAGE)
> @@ -378,8 +379,12 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
> if (WARN_ON(pdpe >= GEN8_LEGACY_PDPES))
> break;
>
> - if (pt_vaddr == NULL)
> - pt_vaddr = kmap_atomic(ppgtt->gen8_pt_pages[pdpe][pde]);
> + if (pt_vaddr == NULL) {
> + struct i915_page_directory_entry *pd = &ppgtt->pdp.page_directory[pdpe];
> + struct page *page_table = pd->page_tables[pde].page;
> +
> + pt_vaddr = kmap_atomic(page_table);
> + }
>
> pt_vaddr[pte] =
> gen8_pte_encode(sg_page_iter_dma_address(&sg_iter),
> @@ -403,29 +408,33 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
> }
> }
>
> -static void gen8_free_page_tables(struct page **pt_pages)
> +static void gen8_free_page_tables(struct i915_page_directory_entry *pd)
> {
> int i;
>
> - if (pt_pages == NULL)
> + if (pd->page_tables == NULL)
> return;
>
> for (i = 0; i < GEN8_PDES_PER_PAGE; i++)
> - if (pt_pages[i])
> - __free_pages(pt_pages[i], 0);
> + if (pd->page_tables[i].page)
> + __free_page(pd->page_tables[i].page);
> }
>
> -static void gen8_ppgtt_free(const struct i915_hw_ppgtt *ppgtt)
> +static void gen8_free_page_directories(struct i915_page_directory_entry *pd)
^
You only free one directory so why plural here?
> +{
If you free the page tables for the directory here..
> + kfree(pd->page_tables);
> + __free_page(pd->page);
> +}
> +
> +static void gen8_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
> {
> int i;
>
> for (i = 0; i < ppgtt->num_pd_pages; i++) {
> - gen8_free_page_tables(ppgtt->gen8_pt_pages[i]);
> - kfree(ppgtt->gen8_pt_pages[i]);
> + gen8_free_page_tables(&ppgtt->pdp.page_directory[i]);
...this loop will be cleaner.
Also consider renaming 'num_pd_pages' to 'num_pd'. But if it does
cause a lot of rebase burden dont worry about it.
> + gen8_free_page_directories(&ppgtt->pdp.page_directory[i]);
> kfree(ppgtt->gen8_pt_dma_addr[i]);
> }
> -
> - __free_pages(ppgtt->pd_pages, get_order(ppgtt->num_pd_pages << PAGE_SHIFT));
> }
>
> static void gen8_ppgtt_unmap_pages(struct i915_hw_ppgtt *ppgtt)
> @@ -460,86 +469,75 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
> gen8_ppgtt_free(ppgtt);
> }
>
> -static struct page **__gen8_alloc_page_tables(void)
> +static int gen8_ppgtt_allocate_dma(struct i915_hw_ppgtt *ppgtt)
> {
> - struct page **pt_pages;
> int i;
>
> - pt_pages = kcalloc(GEN8_PDES_PER_PAGE, sizeof(struct page *), GFP_KERNEL);
> - if (!pt_pages)
> - return ERR_PTR(-ENOMEM);
> -
> - for (i = 0; i < GEN8_PDES_PER_PAGE; i++) {
> - pt_pages[i] = alloc_page(GFP_KERNEL);
> - if (!pt_pages[i])
> - goto bail;
> + for (i = 0; i < ppgtt->num_pd_pages; i++) {
> + ppgtt->gen8_pt_dma_addr[i] = kcalloc(GEN8_PDES_PER_PAGE,
> + sizeof(dma_addr_t),
> + GFP_KERNEL);
> + if (!ppgtt->gen8_pt_dma_addr[i])
> + return -ENOMEM;
> }
>
> - return pt_pages;
> -
> -bail:
> - gen8_free_page_tables(pt_pages);
> - kfree(pt_pages);
> - return ERR_PTR(-ENOMEM);
> + return 0;
> }
>
> -static int gen8_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt,
> - const int max_pdp)
> +static int gen8_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt)
> {
> - struct page **pt_pages[GEN8_LEGACY_PDPES];
> - int i, ret;
> + int i, j;
>
> - for (i = 0; i < max_pdp; i++) {
> - pt_pages[i] = __gen8_alloc_page_tables();
> - if (IS_ERR(pt_pages[i])) {
> - ret = PTR_ERR(pt_pages[i]);
> - goto unwind_out;
> + for (i = 0; i < ppgtt->num_pd_pages; i++) {
> + for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
> + struct i915_page_table_entry *pt = &ppgtt->pdp.page_directory[i].page_tables[j];
> +
> + pt->page = alloc_page(GFP_KERNEL | __GFP_ZERO);
> + if (!pt->page)
> + goto unwind_out;
> }
> }
>
> - /* NB: Avoid touching gen8_pt_pages until last to keep the allocation,
> - * "atomic" - for cleanup purposes.
> - */
> - for (i = 0; i < max_pdp; i++)
> - ppgtt->gen8_pt_pages[i] = pt_pages[i];
> -
> return 0;
>
> unwind_out:
> - while (i--) {
> - gen8_free_page_tables(pt_pages[i]);
> - kfree(pt_pages[i]);
> - }
> + while (i--)
> + gen8_free_page_tables(&ppgtt->pdp.page_directory[i]);
>
> - return ret;
> + return -ENOMEM;
> }
>
> -static int gen8_ppgtt_allocate_dma(struct i915_hw_ppgtt *ppgtt)
> +static int gen8_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt,
> + const int max_pdp)
> {
> int i;
>
> - for (i = 0; i < ppgtt->num_pd_pages; i++) {
> - ppgtt->gen8_pt_dma_addr[i] = kcalloc(GEN8_PDES_PER_PAGE,
> - sizeof(dma_addr_t),
> - GFP_KERNEL);
> - if (!ppgtt->gen8_pt_dma_addr[i])
> - return -ENOMEM;
> - }
> + for (i = 0; i < max_pdp; i++) {
> + struct i915_page_table_entry *pt;
>
> - return 0;
> -}
> + pt = kcalloc(GEN8_PDES_PER_PAGE, sizeof(*pt), GFP_KERNEL);
> + if (!pt)
> + goto unwind_out;
>
> -static int gen8_ppgtt_allocate_page_directories(struct i915_hw_ppgtt *ppgtt,
> - const int max_pdp)
> -{
> - ppgtt->pd_pages = alloc_pages(GFP_KERNEL, get_order(max_pdp << PAGE_SHIFT));
> - if (!ppgtt->pd_pages)
> - return -ENOMEM;
> + ppgtt->pdp.page_directory[i].page = alloc_page(GFP_KERNEL);
> + if (!ppgtt->pdp.page_directory[i].page)
> + goto unwind_out;
If you end up having alloc error here you will leak the previously
allocated pt above.
Also consider that if you do gen8_ppgtt_allocate_page_directory() and
add null check for pd->page in gen8_free_page_directory you should be able to avoid
the unwinding below completely.
> +
> + ppgtt->pdp.page_directory[i].page_tables = pt;
> + }
>
> - ppgtt->num_pd_pages = 1 << get_order(max_pdp << PAGE_SHIFT);
> + ppgtt->num_pd_pages = max_pdp;
> BUG_ON(ppgtt->num_pd_pages > GEN8_LEGACY_PDPES);
>
> return 0;
> +
> +unwind_out:
> + while (i--) {
> + kfree(ppgtt->pdp.page_directory[i].page_tables);
> + __free_page(ppgtt->pdp.page_directory[i].page);
> + }
> +
> + return -ENOMEM;
> }
>
> static int gen8_ppgtt_alloc(struct i915_hw_ppgtt *ppgtt,
> @@ -551,18 +549,19 @@ static int gen8_ppgtt_alloc(struct i915_hw_ppgtt *ppgtt,
> if (ret)
> return ret;
>
> - ret = gen8_ppgtt_allocate_page_tables(ppgtt, max_pdp);
> - if (ret) {
> - __free_pages(ppgtt->pd_pages, get_order(max_pdp << PAGE_SHIFT));
> - return ret;
> - }
> + ret = gen8_ppgtt_allocate_page_tables(ppgtt);
> + if (ret)
> + goto err_out;
>
> ppgtt->num_pd_entries = max_pdp * GEN8_PDES_PER_PAGE;
>
> ret = gen8_ppgtt_allocate_dma(ppgtt);
> - if (ret)
> - gen8_ppgtt_free(ppgtt);
> + if (!ret)
> + return ret;
>
> + /* TODO: Check this for all cases */
The check for zero return and then returning it with the comment is
confusing. Why not just do the same pattern as in above?
if (ret)
goto err_out;
return 0;
-Mika
> +err_out:
> + gen8_ppgtt_free(ppgtt);
> return ret;
> }
>
> @@ -573,7 +572,7 @@ static int gen8_ppgtt_setup_page_directories(struct i915_hw_ppgtt *ppgtt,
> int ret;
>
> pd_addr = pci_map_page(ppgtt->base.dev->pdev,
> - &ppgtt->pd_pages[pd], 0,
> + ppgtt->pdp.page_directory[pd].page, 0,
> PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
>
> ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pd_addr);
> @@ -593,7 +592,7 @@ static int gen8_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt,
> struct page *p;
> int ret;
>
> - p = ppgtt->gen8_pt_pages[pd][pt];
> + p = ppgtt->pdp.page_directory[pd].page_tables[pt].page;
> pt_addr = pci_map_page(ppgtt->base.dev->pdev,
> p, 0, PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
> ret = pci_dma_mapping_error(ppgtt->base.dev->pdev, pt_addr);
> @@ -654,7 +653,7 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt, uint64_t size)
> */
> for (i = 0; i < max_pdp; i++) {
> gen8_ppgtt_pde_t *pd_vaddr;
> - pd_vaddr = kmap_atomic(&ppgtt->pd_pages[i]);
> + pd_vaddr = kmap_atomic(ppgtt->pdp.page_directory[i].page);
> for (j = 0; j < GEN8_PDES_PER_PAGE; j++) {
> dma_addr_t addr = ppgtt->gen8_pt_dma_addr[i][j];
> pd_vaddr[j] = gen8_pde_encode(ppgtt->base.dev, addr,
> @@ -717,7 +716,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
> expected);
> seq_printf(m, "\tPDE: %x\n", pd_entry);
>
> - pt_vaddr = kmap_atomic(ppgtt->pt_pages[pde]);
> + pt_vaddr = kmap_atomic(ppgtt->pd.page_tables[pde].page);
> for (pte = 0; pte < I915_PPGTT_PT_ENTRIES; pte+=4) {
> unsigned long va =
> (pde * PAGE_SIZE * I915_PPGTT_PT_ENTRIES) +
> @@ -922,7 +921,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
> if (last_pte > I915_PPGTT_PT_ENTRIES)
> last_pte = I915_PPGTT_PT_ENTRIES;
>
> - pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);
> + pt_vaddr = kmap_atomic(ppgtt->pd.page_tables[act_pt].page);
>
> for (i = first_pte; i < last_pte; i++)
> pt_vaddr[i] = scratch_pte;
> @@ -951,7 +950,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm,
> pt_vaddr = NULL;
> for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
> if (pt_vaddr == NULL)
> - pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);
> + pt_vaddr = kmap_atomic(ppgtt->pd.page_tables[act_pt].page);
>
> pt_vaddr[act_pte] =
> vm->pte_encode(sg_page_iter_dma_address(&sg_iter),
> @@ -986,8 +985,8 @@ static void gen6_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
>
> kfree(ppgtt->pt_dma_addr);
> for (i = 0; i < ppgtt->num_pd_entries; i++)
> - __free_page(ppgtt->pt_pages[i]);
> - kfree(ppgtt->pt_pages);
> + __free_page(ppgtt->pd.page_tables[i].page);
> + kfree(ppgtt->pd.page_tables);
> }
>
> static void gen6_ppgtt_cleanup(struct i915_address_space *vm)
> @@ -1044,22 +1043,22 @@ alloc:
>
> static int gen6_ppgtt_allocate_page_tables(struct i915_hw_ppgtt *ppgtt)
> {
> + struct i915_page_table_entry *pt;
> int i;
>
> - ppgtt->pt_pages = kcalloc(ppgtt->num_pd_entries, sizeof(struct page *),
> - GFP_KERNEL);
> -
> - if (!ppgtt->pt_pages)
> + pt = kcalloc(ppgtt->num_pd_entries, sizeof(*pt), GFP_KERNEL);
> + if (!pt)
> return -ENOMEM;
>
> for (i = 0; i < ppgtt->num_pd_entries; i++) {
> - ppgtt->pt_pages[i] = alloc_page(GFP_KERNEL);
> - if (!ppgtt->pt_pages[i]) {
> + pt[i].page = alloc_page(GFP_KERNEL);
> + if (!pt->page) {
> gen6_ppgtt_free(ppgtt);
> return -ENOMEM;
> }
> }
>
> + ppgtt->pd.page_tables = pt;
> return 0;
> }
>
> @@ -1094,9 +1093,11 @@ static int gen6_ppgtt_setup_page_tables(struct i915_hw_ppgtt *ppgtt)
> int i;
>
> for (i = 0; i < ppgtt->num_pd_entries; i++) {
> + struct page *page;
> dma_addr_t pt_addr;
>
> - pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i], 0, 4096,
> + page = ppgtt->pd.page_tables[i].page;
> + pt_addr = pci_map_page(dev->pdev, page, 0, 4096,
> PCI_DMA_BIDIRECTIONAL);
>
> if (pci_dma_mapping_error(dev->pdev, pt_addr)) {
> @@ -1140,7 +1141,7 @@ static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
> ppgtt->base.insert_entries = gen6_ppgtt_insert_entries;
> ppgtt->base.cleanup = gen6_ppgtt_cleanup;
> ppgtt->base.start = 0;
> - ppgtt->base.total = ppgtt->num_pd_entries * I915_PPGTT_PT_ENTRIES * PAGE_SIZE;
> + ppgtt->base.total = ppgtt->num_pd_entries * I915_PPGTT_PT_ENTRIES * PAGE_SIZE;
> ppgtt->debug_dump = gen6_dump_ppgtt;
>
> ppgtt->pd_offset =
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 8f76990..d9bc375 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -187,6 +187,20 @@ struct i915_vma {
> u32 flags);
> };
>
> +struct i915_page_table_entry {
> + struct page *page;
> +};
> +
> +struct i915_page_directory_entry {
> + struct page *page; /* NULL for GEN6-GEN7 */
> + struct i915_page_table_entry *page_tables;
> +};
> +
> +struct i915_page_directory_pointer_entry {
> + /* struct page *page; */
> + struct i915_page_directory_entry page_directory[GEN8_LEGACY_PDPES];
> +};
> +
> struct i915_address_space {
> struct drm_mm mm;
> struct drm_device *dev;
> @@ -272,11 +286,6 @@ struct i915_hw_ppgtt {
> unsigned num_pd_entries;
> unsigned num_pd_pages; /* gen8+ */
> union {
> - struct page **pt_pages;
> - struct page **gen8_pt_pages[GEN8_LEGACY_PDPES];
> - };
> - struct page *pd_pages;
> - union {
> uint32_t pd_offset;
> dma_addr_t pd_dma_addr[GEN8_LEGACY_PDPES];
> };
> @@ -284,6 +293,10 @@ struct i915_hw_ppgtt {
> dma_addr_t *pt_dma_addr;
> dma_addr_t *gen8_pt_dma_addr[GEN8_LEGACY_PDPES];
> };
> + union {
> + struct i915_page_directory_pointer_entry pdp;
> + struct i915_page_directory_entry pd;
> + };
>
> struct drm_i915_file_private *file_priv;
>
> --
> 2.1.1
>
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