On 14/09/2023 23:38, Adrián Larumbe wrote:
> BO's RSS is updated every time new pages are allocated on demand and mapped
> for the object at GPU page fault's IRQ handler, but only for heap buffers.
> The reason this is unnecessary for non-heap buffers is that they are mapped
> onto the GPU's VA space and backed by physical memory in their entirety at
> BO creation time.
>
> This calculation is unnecessary for imported PRIME objects, since heap
> buffers cannot be exported by our driver, and the actual BO RSS size is the
> one reported in its attached dmabuf structure.
>
> Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
> Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Am I missing something, or are we missing a way of resetting
heap_rss_size when the shrinker purges? It looks like after several
grow/purge cycles, heap_rss_size could actually grow to be larger than
the BO which is clearly wrong.
Steve
> ---
> drivers/gpu/drm/panfrost/panfrost_gem.c | 15 +++++++++++++++
> drivers/gpu/drm/panfrost/panfrost_gem.h | 5 +++++
> drivers/gpu/drm/panfrost/panfrost_mmu.c | 1 +
> 3 files changed, 21 insertions(+)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c b/drivers/gpu/drm/panfrost/panfrost_gem.c
> index 7d8f83d20539..4365434b48db 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
> @@ -208,6 +208,20 @@ static enum drm_gem_object_status panfrost_gem_status(struct drm_gem_object *obj
> return res;
> }
>
> +static size_t panfrost_gem_rss(struct drm_gem_object *obj)
> +{
> + struct panfrost_gem_object *bo = to_panfrost_bo(obj);
> +
> + if (bo->is_heap) {
> + return bo->heap_rss_size;
> + } else if (bo->base.pages) {
> + WARN_ON(bo->heap_rss_size);
> + return bo->base.base.size;
> + } else {
> + return 0;
> + }
> +}
> +
> static const struct drm_gem_object_funcs panfrost_gem_funcs = {
> .free = panfrost_gem_free_object,
> .open = panfrost_gem_open,
> @@ -220,6 +234,7 @@ static const struct drm_gem_object_funcs panfrost_gem_funcs = {
> .vunmap = drm_gem_shmem_object_vunmap,
> .mmap = drm_gem_shmem_object_mmap,
> .status = panfrost_gem_status,
> + .rss = panfrost_gem_rss,
> .vm_ops = &drm_gem_shmem_vm_ops,
> };
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
> index ad2877eeeccd..13c0a8149c3a 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
> @@ -36,6 +36,11 @@ struct panfrost_gem_object {
> */
> atomic_t gpu_usecount;
>
> + /*
> + * Object chunk size currently mapped onto physical memory
> + */
> + size_t heap_rss_size;
> +
> bool noexec :1;
> bool is_heap :1;
> };
> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> index d54d4e7b2195..7b1490cdaa48 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> @@ -522,6 +522,7 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
> IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
>
> bomapping->active = true;
> + bo->heap_rss_size += SZ_2;
>
> dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr);
>
