[PATCH v7 3/3] drm/i915/ttm: Use TTM for system memory
Matthew Auld
matthew.william.auld at gmail.com
Tue Jun 22 10:55:23 UTC 2021
On Tue, 22 Jun 2021 at 10:34, Thomas Hellström
<thomas.hellstrom at linux.intel.com> wrote:
>
> For discrete, use TTM for both cached and WC system memory. That means
> we currently rely on the TTM memory accounting / shrinker. For cached
> system memory we should consider remaining shmem-backed, which can be
> implemented from our ttm_tt_populate callback. We can then also reuse our
> own very elaborate shrinker for that memory.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> ---
> v2:
> - Fix IS_ERR_OR_NULL() check to IS_ERR() (Reported by Matthew Auld)
> v3:
> - Commit message typo fix
> v6:
> - Fix TODO:s for supporting system memory with TTM.
> - Update the object GEM region after a TTM move if compatible.
> - Add a couple of warnings for shmem on DGFX.
> ---
> drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 3 ++
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 51 +++++++++++++++++-----
> drivers/gpu/drm/i915/i915_drv.h | 3 --
> drivers/gpu/drm/i915/intel_memory_region.c | 7 ++-
> drivers/gpu/drm/i915/intel_memory_region.h | 8 ++++
> 5 files changed, 58 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> index 7aa1c95c7b7d..3648ae1d6628 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> @@ -284,6 +284,7 @@ __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
> bool needs_clflush)
> {
> GEM_BUG_ON(obj->mm.madv == __I915_MADV_PURGED);
> + GEM_WARN_ON(IS_DGFX(to_i915(obj->base.dev)));
>
> if (obj->mm.madv == I915_MADV_DONTNEED)
> obj->mm.dirty = false;
> @@ -302,6 +303,7 @@ void i915_gem_object_put_pages_shmem(struct drm_i915_gem_object *obj, struct sg_
> struct pagevec pvec;
> struct page *page;
>
> + GEM_WARN_ON(IS_DGFX(to_i915(obj->base.dev)));
> __i915_gem_object_release_shmem(obj, pages, true);
>
> i915_gem_gtt_finish_pages(obj, pages);
> @@ -560,6 +562,7 @@ i915_gem_object_create_shmem_from_data(struct drm_i915_private *dev_priv,
> resource_size_t offset;
> int err;
>
> + GEM_WARN_ON(IS_DGFX(dev_priv));
> obj = i915_gem_object_create_shmem(dev_priv, round_up(size, PAGE_SIZE));
> if (IS_ERR(obj))
> return obj;
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 966b292d07da..07097f150065 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -286,6 +286,25 @@ static void i915_ttm_adjust_gem_after_move(struct drm_i915_gem_object *obj)
> {
> struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
> unsigned int cache_level;
> + unsigned int i;
> +
> + /*
> + * If object was moved to an allowable region, update the object
> + * region to consider it migrated. Note that if it's currently not
> + * in an allowable region, it's evicted and we don't update the
> + * object region.
> + */
> + if (intel_region_to_ttm_type(obj->mm.region) != bo->resource->mem_type) {
> + for (i = 0; i < obj->mm.n_placements; ++i) {
> + struct intel_memory_region *mr = obj->mm.placements[i];
> +
> + if (intel_region_to_ttm_type(mr) == bo->resource->mem_type &&
> + mr != obj->mm.region) {
> + intel_memory_region_put(obj->mm.region);
> + obj->mm.region = intel_memory_region_get(mr);
break;?
i915_gem_object_{init, release}_memory_region?
There is also the region_link stuff, but I guess we can nuke that?
> + }
> + }
> + }
>
> obj->mem_flags &= ~(I915_BO_FLAG_STRUCT_PAGE | I915_BO_FLAG_IOMEM);
>
> @@ -615,13 +634,6 @@ static int i915_ttm_get_pages(struct drm_i915_gem_object *obj)
> /* Move to the requested placement. */
> i915_ttm_placement_from_obj(obj, &requested, busy, &placement);
>
> - /*
> - * For now we support LMEM only with TTM.
> - * TODO: Remove with system support
> - */
> - GEM_BUG_ON(requested.mem_type < I915_PL_LMEM0 ||
> - busy[0].mem_type < I915_PL_LMEM0);
> -
> /* First try only the requested placement. No eviction. */
> real_num_busy = fetch_and_zero(&placement.num_busy_placement);
> ret = ttm_bo_validate(bo, &placement, &ctx);
> @@ -635,9 +647,6 @@ static int i915_ttm_get_pages(struct drm_i915_gem_object *obj)
> ret == -EAGAIN)
> return ret;
>
> - /* TODO: Remove this when we support system as TTM. */
> - real_num_busy = 1;
> -
> /*
> * If the initial attempt fails, allow all accepted placements,
> * evicting if necessary.
> @@ -872,3 +881,25 @@ int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
>
> return 0;
> }
> +
> +static const struct intel_memory_region_ops ttm_system_region_ops = {
> + .init_object = __i915_gem_ttm_object_init,
> +};
> +
> +struct intel_memory_region *
> +i915_gem_ttm_system_setup(struct drm_i915_private *i915,
> + u16 type, u16 instance)
> +{
> + struct intel_memory_region *mr;
> +
> + mr = intel_memory_region_create(i915, 0,
> + totalram_pages() << PAGE_SHIFT,
> + PAGE_SIZE, 0,
> + type, instance,
> + &ttm_system_region_ops);
> + if (IS_ERR(mr))
> + return mr;
> +
> + intel_memory_region_set_name(mr, "system-ttm");
> + return mr;
> +}
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 01e11fe38642..bfbfbae57573 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1751,9 +1751,6 @@ void i915_gem_cleanup_userptr(struct drm_i915_private *dev_priv);
> void i915_gem_init_early(struct drm_i915_private *dev_priv);
> void i915_gem_cleanup_early(struct drm_i915_private *dev_priv);
>
> -struct intel_memory_region *i915_gem_shmem_setup(struct drm_i915_private *i915,
> - u16 type, u16 instance);
> -
> static inline void i915_gem_drain_freed_objects(struct drm_i915_private *i915)
> {
> /*
> diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
> index df59f884d37c..779eb2fa90b6 100644
> --- a/drivers/gpu/drm/i915/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/intel_memory_region.c
> @@ -173,7 +173,12 @@ int intel_memory_regions_hw_probe(struct drm_i915_private *i915)
> instance = intel_region_map[i].instance;
> switch (type) {
> case INTEL_MEMORY_SYSTEM:
> - mem = i915_gem_shmem_setup(i915, type, instance);
> + if (IS_DGFX(i915))
> + mem = i915_gem_ttm_system_setup(i915, type,
> + instance);
> + else
> + mem = i915_gem_shmem_setup(i915, type,
> + instance);
> break;
> case INTEL_MEMORY_STOLEN_LOCAL:
> mem = i915_gem_stolen_lmem_setup(i915, type, instance);
> diff --git a/drivers/gpu/drm/i915/intel_memory_region.h b/drivers/gpu/drm/i915/intel_memory_region.h
> index 2be8433d373a..b1b9e461d53b 100644
> --- a/drivers/gpu/drm/i915/intel_memory_region.h
> +++ b/drivers/gpu/drm/i915/intel_memory_region.h
> @@ -125,4 +125,12 @@ intel_memory_region_set_name(struct intel_memory_region *mem,
> int intel_memory_region_reserve(struct intel_memory_region *mem,
> resource_size_t offset,
> resource_size_t size);
> +
> +struct intel_memory_region *
> +i915_gem_ttm_system_setup(struct drm_i915_private *i915,
> + u16 type, u16 instance);
> +struct intel_memory_region *
> +i915_gem_shmem_setup(struct drm_i915_private *i915,
> + u16 type, u16 instance);
> +
> #endif
> --
> 2.31.1
>
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