[PATCH 2/2] drm/amdgpu: enable huge page handling in the VM v5
Felix Kuehling
felix.kuehling at amd.com
Wed Jul 19 22:09:21 UTC 2017
Two nit-picks inline. Otherwise this series is Reviewed-and-tested-by:
Felix Kuehling <Felix.Kuehling at amd.com>
That said, I was not able to measure any performance improvement on
Vega10 using mixbench yet. I checked that the same test is sensitive to
TLB optimizations on Fiji. So probably we're still missing something.
Regards,
Felix
On 17-07-19 11:26 AM, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
>
> The hardware can use huge pages to map 2MB of address space with only one PDE.
>
> v2: few cleanups and rebased
> v3: skip PT updates if we are using the PDE
> v4: rebased, added support for CPU based updates
> v5: fix CPU based updates once more
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 119 +++++++++++++++++++++++++++------
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 4 ++
> 2 files changed, 103 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index a3dbebe..950777e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -351,6 +351,7 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
>
> entry->bo = pt;
> entry->addr = 0;
> + entry->huge_page = false;
> }
>
> if (level < adev->vm_manager.num_level) {
> @@ -1116,7 +1117,8 @@ static int amdgpu_vm_update_level(struct amdgpu_device *adev,
>
> pt = amdgpu_bo_gpu_offset(bo);
> pt = amdgpu_gart_get_vm_pde(adev, pt);
> - if (parent->entries[pt_idx].addr == pt)
> + if (parent->entries[pt_idx].addr == pt ||
> + parent->entries[pt_idx].huge_page)
> continue;
>
> parent->entries[pt_idx].addr = pt;
> @@ -1257,29 +1259,95 @@ int amdgpu_vm_update_directories(struct amdgpu_device *adev,
> }
>
> /**
> - * amdgpu_vm_find_pt - find the page table for an address
> + * amdgpu_vm_find_entry - find the entry for an address
> *
> * @p: see amdgpu_pte_update_params definition
> * @addr: virtual address in question
> + * @entry: resulting entry or NULL
> + * @parent: parent entry
> *
> - * Find the page table BO for a virtual address, return NULL when none found.
> + * Find the vm_pt entry and it's parent for the given address.
> */
> -static struct amdgpu_bo *amdgpu_vm_get_pt(struct amdgpu_pte_update_params *p,
> - uint64_t addr)
> +void amdgpu_vm_get_entry(struct amdgpu_pte_update_params *p, uint64_t addr,
> + struct amdgpu_vm_pt **entry,
> + struct amdgpu_vm_pt **parent)
> {
> - struct amdgpu_vm_pt *entry = &p->vm->root;
> unsigned idx, level = p->adev->vm_manager.num_level;
>
> - while (entry->entries) {
> + *parent = NULL;
> + *entry = &p->vm->root;
> + while ((*entry)->entries) {
> idx = addr >> (p->adev->vm_manager.block_size * level--);
> - idx %= amdgpu_bo_size(entry->bo) / 8;
> - entry = &entry->entries[idx];
> + idx %= amdgpu_bo_size((*entry)->bo) / 8;
> + *parent = *entry;
> + *entry = &(*entry)->entries[idx];
> }
>
> if (level)
> - return NULL;
> + *entry = NULL;
> +}
> +
> +/**
> + * amdgpu_vm_handle_huge_pages - handle updating the PD with huge pages
> + *
> + * @p: see amdgpu_pte_update_params definition
> + * @entry: vm_pt entry to check
> + * @parent: parent entry
> + * @nptes: number of PTEs updated with this operation
> + * @dst: destination address where the PTEs should point to
> + * @flags: access flags fro the PTEs
> + *
> + * Check if we can update the PD with a huge page.
> + */
> +static int amdgpu_vm_handle_huge_pages(struct amdgpu_pte_update_params *p,
> + struct amdgpu_vm_pt *entry,
> + struct amdgpu_vm_pt *parent,
> + unsigned nptes, uint64_t dst,
> + uint64_t flags)
> +{
> + bool use_cpu_update = (p->func == amdgpu_vm_cpu_set_ptes);
> + uint64_t pd_addr, pde;
> + int r;
>
> - return entry->bo;
> + /* In the case of a mixed PT the PDE must point to it*/
> + if (p->adev->asic_type < CHIP_VEGA10 ||
> + nptes != AMDGPU_VM_PTE_COUNT(p->adev) ||
> + p->func == amdgpu_vm_do_copy_ptes ||
> + !(flags & AMDGPU_PTE_VALID)) {
> +
> + dst = amdgpu_bo_gpu_offset(entry->bo);
> + dst = amdgpu_gart_get_vm_pde(p->adev, dst);
> + flags = AMDGPU_PTE_VALID;
> + } else {
> + flags |= AMDGPU_PDE_PTE;
> + }
> +
> + if (entry->addr == dst &&
> + entry->huge_page == !!(flags & AMDGPU_PDE_PTE))
> + return 0;
> +
> + entry->addr = dst;
> + entry->huge_page = !!(flags & AMDGPU_PDE_PTE);
> +
> + if (use_cpu_update) {
> + r = amdgpu_bo_kmap(parent->bo, (void *)&pd_addr);
> + if (r)
> + return r;
> +
> + pde = pd_addr + (entry - parent->entries) * 8;
> + amdgpu_vm_cpu_set_ptes(p, pde, dst, 1, 0, flags);
> + } else {
> + if (parent->bo->shadow) {
> + pd_addr = amdgpu_bo_gpu_offset(parent->bo->shadow);
> + pde = pd_addr + (entry - parent->entries) * 8;
> + amdgpu_vm_do_set_ptes(p, pde, dst, 1, 0, flags);
> + }
> + pd_addr = amdgpu_bo_gpu_offset(parent->bo);
> + pde = pd_addr + (entry - parent->entries) * 8;
> + amdgpu_vm_do_set_ptes(p, pde, dst, 1, 0, flags);
> + }
> +
> + return 0;
> }
>
> /**
> @@ -1306,22 +1374,31 @@ static int amdgpu_vm_update_ptes(struct amdgpu_pte_update_params *params,
> struct amdgpu_bo *pt;
> unsigned nptes;
> bool use_cpu_update = (params->func == amdgpu_vm_cpu_set_ptes);
> -
> + int r;
>
> /* walk over the address space and update the page tables */
> - for (addr = start; addr < end; addr += nptes) {
> - pt = amdgpu_vm_get_pt(params, addr);
> - if (!pt) {
> - pr_err("PT not found, aborting update_ptes\n");
> - return -EINVAL;
> - }
> + for (addr = start; addr < end; addr += nptes,
> + dst += nptes * AMDGPU_GPU_PAGE_SIZE) {
> + struct amdgpu_vm_pt *entry, *parent;
> +
> + amdgpu_vm_get_entry(params, addr, &entry, &parent);
> + if (!entry)
> + return -ENOENT;
ENOENT means "no such file or directory". Not sure that makes sense
outside of file system code.
>
> if ((addr & ~mask) == (end & ~mask))
> nptes = end - addr;
> else
> nptes = AMDGPU_VM_PTE_COUNT(adev) - (addr & mask);
>
> + r = amdgpu_vm_handle_huge_pages(params, entry, parent,
> + nptes, dst, flags);
> + if (r)
> + return r;
>
> + if (entry->huge_page)
> + continue;
> +
> + pt = entry->bo;
> if (use_cpu_update) {
> pe_start = (unsigned long)pt->kptr;
> } else {
> @@ -1337,8 +1414,6 @@ static int amdgpu_vm_update_ptes(struct amdgpu_pte_update_params *params,
> pe_start += (addr & mask) * 8;
> params->func(params, pe_start, dst, nptes,
> AMDGPU_GPU_PAGE_SIZE, flags);
> -
> - dst += nptes * AMDGPU_GPU_PAGE_SIZE;
> }
>
> return 0;
> @@ -1490,6 +1565,9 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
> /* padding, etc. */
> ndw = 64;
>
> + /* one PDE write for each huge page */
> + ndw += ((nptes >> adev->vm_manager.block_size) + 1) * 7;
I think page directory updates only need 6 dwords. That's what
update_level uses anyway.
> +
> if (src) {
> /* only copy commands needed */
> ndw += ncmds * 7;
> @@ -1569,6 +1647,7 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
>
> error_free:
> amdgpu_job_free(job);
> + amdgpu_vm_invalidate_level(&vm->root);
> return r;
> }
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> index c4f5d1f..34d9174 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -70,6 +70,9 @@ struct amdgpu_bo_list_entry;
> /* TILED for VEGA10, reserved for older ASICs */
> #define AMDGPU_PTE_PRT (1ULL << 51)
>
> +/* PDE is handled as PTE for VEGA10 */
> +#define AMDGPU_PDE_PTE (1ULL << 54)
> +
> /* VEGA10 only */
> #define AMDGPU_PTE_MTYPE(a) ((uint64_t)a << 57)
> #define AMDGPU_PTE_MTYPE_MASK AMDGPU_PTE_MTYPE(3ULL)
> @@ -100,6 +103,7 @@ struct amdgpu_bo_list_entry;
> struct amdgpu_vm_pt {
> struct amdgpu_bo *bo;
> uint64_t addr;
> + bool huge_page;
>
> /* array of page tables, one for each directory entry */
> struct amdgpu_vm_pt *entries;
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