On Mon, Nov 26, 2018 at 8:46 AM Bas Nieuwenhuizen <ba...@chromium.org> wrote:
> patches 4-7 are > > Reviewed-by: Bas Nieuwenhuizen <b...@basnieuwenhuizen.nl> > > though I agree with Christian that it would be nice to get a case > where 7 improves things before we submit it. > > For patches 1-3 I need to dive into the slab allocator before I have > enough knowledge to review. > It's actually pretty simple. Each slab buffer contains suballocations of the same size. E.g. one 2M slab can only have 16 128K suballocations. If you want a 64K buffer, you have to allocate a separate 2M slab with 32 64K suballocations. If you need to allocate just 512B, you need another 2MB slab. This wastes memory in 2 ways: 1) a 129K buffer will have to be allocated as a 256K buffer, because the allocation size has to be a power of two, wasting space 2) there will be too many 2MB slabs, one slab for each size (from 2^9 to 2^18), each having some unused space, wasting space 3) having too many 2K and smaller allocations actually decreases memory usage, because the minimum kernel allocation size is 4K Problem 2 is mitigated by layering slab allocators on top of each other. The top slab allocator can only allocate sizes 2^17 to 2^18, so you only need two 2M slabs to cover all your needs. The middle allocator uses the top allocator and allocates slabs of size 2^17 and uses it to allocate 2^13 to 2^16 sizes. The bottom allocator allocates slabs of size 2^13 and uses it allocate 2^9 to 2^12 sizes. Marek On Sat, Nov 24, 2018 at 12:41 AM Marek Olšák <mar...@gmail.com> wrote: > > > > From: Marek Olšák <marek.ol...@amd.com> > > > > --- > > src/gallium/winsys/amdgpu/drm/amdgpu_bo.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c > b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c > > index a9271c33ee9..36e2c4ec0dc 100644 > > --- a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c > > +++ b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c > > @@ -449,24 +449,29 @@ static struct amdgpu_winsys_bo > *amdgpu_create_bo(struct amdgpu_winsys *ws, > > r = amdgpu_bo_alloc(ws->dev, &request, &buf_handle); > > if (r) { > > fprintf(stderr, "amdgpu: Failed to allocate a buffer:\n"); > > fprintf(stderr, "amdgpu: size : %"PRIu64" bytes\n", size); > > fprintf(stderr, "amdgpu: alignment : %u bytes\n", alignment); > > fprintf(stderr, "amdgpu: domains : %u\n", initial_domain); > > goto error_bo_alloc; > > } > > > > va_gap_size = ws->check_vm ? MAX2(4 * alignment, 64 * 1024) : 0; > > + > > + unsigned vm_alignment = alignment; > > + > > + /* Increase the VM alignment for faster address translation. */ > > if (size > ws->info.pte_fragment_size) > > - alignment = MAX2(alignment, ws->info.pte_fragment_size); > > + vm_alignment = MAX2(vm_alignment, ws->info.pte_fragment_size); > > + > > r = amdgpu_va_range_alloc(ws->dev, amdgpu_gpu_va_range_general, > > - size + va_gap_size, alignment, 0, &va, > &va_handle, > > + size + va_gap_size, vm_alignment, 0, &va, > &va_handle, > > (flags & RADEON_FLAG_32BIT ? > AMDGPU_VA_RANGE_32_BIT : 0) | > > AMDGPU_VA_RANGE_HIGH); > > if (r) > > goto error_va_alloc; > > > > unsigned vm_flags = AMDGPU_VM_PAGE_READABLE | > > AMDGPU_VM_PAGE_EXECUTABLE; > > > > if (!(flags & RADEON_FLAG_READ_ONLY)) > > vm_flags |= AMDGPU_VM_PAGE_WRITEABLE; > > -- > > 2.17.1 > > > > _______________________________________________ > > mesa-dev mailing list > > mesa-dev@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/mesa-dev >
_______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev