[v2,0/4] drm/i915/ttm: Evict and store of compressed object

Message

Ramalingam C March 1, 2022, 9:53 p.m. UTC

On Xe-HP and later devices, we use dedicated compression control
state (CCS) stored in local memory for each surface, to support
the 3D and media compression formats.

The memory required for the CCS of the entire local memory is
1/256 of the local memory size. So before the kernel
boot, the required memory is reserved for the CCS data and a
secure register will be programmed with the CCS base address

So when we allocate a object in local memory we dont need to explicitly
allocate the space for ccs data. But when we evict the obj into the smem
to hold the compression related data along with the obj we need smem
space of obj_size + (obj_size/256).

Hence when we create smem for an obj with lmem placement possibility we
create with the extra space.

When we are swapping out the local memory obj on flat-ccs capable platform,
we need to capture the ccs data too along with main meory and we need to
restore it when we are swapping in the content.

When lmem object is swapped into a smem obj, smem obj will
have the extra pages required to hold the ccs data corresponding to the
lmem main memory. So main memory of lmem will be copied into the initial
pages of the smem and then ccs data corresponding to the main memory
will be copied to the subsequent pages of smem.

Swapin happens exactly in reverse order. First main memory of lmem is
restored from the smem's initial pages and the ccs data will be restored
from the subsequent pages of smem.

Extracting and restoring the CCS data is done through a special cmd called
XY_CTRL_SURF_COPY_BLT

Test-with: [e-mail]

Ayaz A Siddiqui (1):
  drm/i915/gt: Clear compress metadata for Xe_HP platforms

Ramalingam C (3):
  drm/ttm: parameter to add extra pages into ttm_tt
  drm/i915/gem: Extra pages in ttm_tt for ccs data
  drm/i915/migrate: Evict and restore the flatccs capable lmem obj

 drivers/gpu/drm/drm_gem_vram_helper.c        |   2 +-
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c      |  23 +-
 drivers/gpu/drm/i915/gt/intel_gpu_commands.h |  15 +
 drivers/gpu/drm/i915/gt/intel_migrate.c      | 327 +++++++++++++++++--
 drivers/gpu/drm/qxl/qxl_ttm.c                |   2 +-
 drivers/gpu/drm/ttm/ttm_agp_backend.c        |   2 +-
 drivers/gpu/drm/ttm/ttm_tt.c                 |  12 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c   |   2 +-
 include/drm/ttm/ttm_tt.h                     |   4 +-
 9 files changed, 357 insertions(+), 32 deletions(-)

Comments

Nirmoy Das March 2, 2022, 3:31 p.m. UTC | #1

Reviewed-by: Nirmoy Das <[e-mail]> for the series as well.

On 01/03/2022 22:53, Ramalingam C wrote:
> On Xe-HP and later devices, we use dedicated compression control
> state (CCS) stored in local memory for each surface, to support
> the 3D and media compression formats.
>
> The memory required for the CCS of the entire local memory is
> 1/256 of the local memory size. So before the kernel
> boot, the required memory is reserved for the CCS data and a
> secure register will be programmed with the CCS base address
>
> So when we allocate a object in local memory we dont need to explicitly
> allocate the space for ccs data. But when we evict the obj into the smem
> to hold the compression related data along with the obj we need smem
> space of obj_size + (obj_size/256).
>
> Hence when we create smem for an obj with lmem placement possibility we
> create with the extra space.
>
> When we are swapping out the local memory obj on flat-ccs capable platform,
> we need to capture the ccs data too along with main meory and we need to
> restore it when we are swapping in the content.
>
> When lmem object is swapped into a smem obj, smem obj will
> have the extra pages required to hold the ccs data corresponding to the
> lmem main memory. So main memory of lmem will be copied into the initial
> pages of the smem and then ccs data corresponding to the main memory
> will be copied to the subsequent pages of smem.
>
> Swapin happens exactly in reverse order. First main memory of lmem is
> restored from the smem's initial pages and the ccs data will be restored
> from the subsequent pages of smem.
>
> Extracting and restoring the CCS data is done through a special cmd called
> XY_CTRL_SURF_COPY_BLT
>
> Test-with: [e-mail]
>
> Ayaz A Siddiqui (1):
>    drm/i915/gt: Clear compress metadata for Xe_HP platforms
>
> Ramalingam C (3):
>    drm/ttm: parameter to add extra pages into ttm_tt
>    drm/i915/gem: Extra pages in ttm_tt for ccs data
>    drm/i915/migrate: Evict and restore the flatccs capable lmem obj
>
>   drivers/gpu/drm/drm_gem_vram_helper.c        |   2 +-
>   drivers/gpu/drm/i915/gem/i915_gem_ttm.c      |  23 +-
>   drivers/gpu/drm/i915/gt/intel_gpu_commands.h |  15 +
>   drivers/gpu/drm/i915/gt/intel_migrate.c      | 327 +++++++++++++++++--
>   drivers/gpu/drm/qxl/qxl_ttm.c                |   2 +-
>   drivers/gpu/drm/ttm/ttm_agp_backend.c        |   2 +-
>   drivers/gpu/drm/ttm/ttm_tt.c                 |  12 +-
>   drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c   |   2 +-
>   include/drm/ttm/ttm_tt.h                     |   4 +-
>   9 files changed, 357 insertions(+), 32 deletions(-)
>