Am 2021-07-13 um 9:32 a.m. schrieb Christian König:
> For allocations larger than 48MiB we need more than a page for the
> housekeeping in the worst case resulting in the usual vmalloc overhead.
>
> Try to avoid this by assuming the good case and only falling back to the
> worst case if this didn't worked.
>
> Signed-off-by: Christian König <christian.koe...@amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 80 +++++++++++++++-----
> 1 file changed, 60 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 2fd77c36a1ff..ab8c5e28df7b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -361,19 +361,23 @@ static void amdgpu_vram_mgr_virt_start(struct
> ttm_resource *mem,
> * @man: TTM memory type manager
> * @tbo: TTM BO we need this range for
> * @place: placement flags and restrictions
> - * @mem: the resulting mem object
> + * @num_nodes: number of page nodes to use.
> + * @pages_per_node: number of pages per node to use.
> + * @res: the resulting mem object
> *
> * Allocate VRAM for the given BO.
> */
> static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
> struct ttm_buffer_object *tbo,
> const struct ttm_place *place,
> + unsigned long num_nodes,
> + unsigned long pages_per_node,
> struct ttm_resource **res)
> {
> - unsigned long lpfn, num_nodes, pages_per_node, pages_left, pages;
> struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
> struct amdgpu_device *adev = to_amdgpu_device(mgr);
> uint64_t vis_usage = 0, mem_bytes, max_bytes;
> + unsigned long lpfn, pages_left, pages;
> struct ttm_range_mgr_node *node;
> struct drm_mm *mm = &mgr->mm;
> enum drm_mm_insert_mode mode;
> @@ -395,21 +399,6 @@ static int amdgpu_vram_mgr_new(struct
> ttm_resource_manager *man,
> goto error_sub;
> }
>
> - if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
> - pages_per_node = ~0ul;
> - num_nodes = 1;
> - } else {
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> - pages_per_node = HPAGE_PMD_NR;
> -#else
> - /* default to 2MB */
> - pages_per_node = 2UL << (20UL - PAGE_SHIFT);
> -#endif
> - pages_per_node = max_t(uint32_t, pages_per_node,
> - tbo->page_alignment);
> - num_nodes = DIV_ROUND_UP_ULL(PFN_UP(mem_bytes), pages_per_node);
> - }
> -
> node = kvmalloc(struct_size(node, mm_nodes, num_nodes),
> GFP_KERNEL | __GFP_ZERO);
> if (!node) {
> @@ -431,10 +420,15 @@ static int amdgpu_vram_mgr_new(struct
> ttm_resource_manager *man,
> i = 0;
> spin_lock(&mgr->lock);
> while (pages_left) {
> - uint32_t alignment = tbo->page_alignment;
> + unsigned long alignment = tbo->page_alignment;
> +
> + if (i >= num_nodes) {
> + r = -E2BIG;
> + goto error_free;
> + }
>
> if (pages >= pages_per_node)
> - alignment = pages_per_node;
> + alignment = max(alignment, pages_per_node);
I don't understand this change. Is this an unrelated fix? pages_per_node
is already bumped up to tbo->page_alignment in amdgpu_vram_mgr_alloc. So
this "max" operation here seems redundant.
Other than that, the patch is
Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>
@JinHuiEric, can you confirm the performance improvement?
Thanks,
Felix
>
> r = drm_mm_insert_node_in_range(mm, &node->mm_nodes[i], pages,
> alignment, 0, place->fpfn,
> @@ -483,6 +477,52 @@ static int amdgpu_vram_mgr_new(struct
> ttm_resource_manager *man,
> return r;
> }
>
> +/**
> + * amdgpu_vram_mgr_alloc - allocate new range
> + *
> + * @man: TTM memory type manager
> + * @tbo: TTM BO we need this range for
> + * @place: placement flags and restrictions
> + * @res: the resulting mem object
> + *
> + * Allocate VRAM for the given BO.
> + */
> +static int amdgpu_vram_mgr_alloc(struct ttm_resource_manager *man,
> + struct ttm_buffer_object *tbo,
> + const struct ttm_place *place,
> + struct ttm_resource **res)
> +{
> + unsigned long num_nodes, pages_per_node;
> + struct ttm_range_mgr_node *node;
> + int r;
> +
> + if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
> + return amdgpu_vram_mgr_new(man, tbo, place, 1, ~0ul, res);
> +
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> + pages_per_node = HPAGE_PMD_NR;
> +#else
> + /* default to 2MB */
> + pages_per_node = 2UL << (20UL - PAGE_SHIFT);
> +#endif
> + pages_per_node = max_t(uint32_t, pages_per_node, tbo->page_alignment);
> + num_nodes = DIV_ROUND_UP_ULL(PFN_UP(tbo->base.size), pages_per_node);
> +
> + if (struct_size(node, mm_nodes, num_nodes) > PAGE_SIZE) {
> + size_t size = PAGE_SIZE;
> +
> + size -= sizeof(struct ttm_range_mgr_node);
> + size /= sizeof(struct drm_mm_node);
> + r = amdgpu_vram_mgr_new(man, tbo, place, size, pages_per_node,
> + res);
> + if (r != -E2BIG)
> + return r;
> + }
> +
> + return amdgpu_vram_mgr_new(man, tbo, place, num_nodes, pages_per_node,
> + res);
> +}
> +
> /**
> * amdgpu_vram_mgr_del - free ranges
> *
> @@ -680,7 +720,7 @@ static void amdgpu_vram_mgr_debug(struct
> ttm_resource_manager *man,
> }
>
> static const struct ttm_resource_manager_func amdgpu_vram_mgr_func = {
> - .alloc = amdgpu_vram_mgr_new,
> + .alloc = amdgpu_vram_mgr_alloc,
> .free = amdgpu_vram_mgr_del,
> .debug = amdgpu_vram_mgr_debug
> };
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