[PATCH 03/36] drm/amdgpu: remove fence slab

[Christian König]

On 6/17/25 05:07, Alex Deucher wrote:
> Just use kmalloc for the fences in the rare case we need
> an independent fence.
> 
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>

This also means that we can nuke the two different fence implementations here, see amdgpu_job_fence_free().

But this patch alone is Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu.h       |  3 ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c   |  5 -----
>  drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 21 +++------------------
>  3 files changed, 3 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index 5e2f086d2c99e..534d999b1433d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -470,9 +470,6 @@ struct amdgpu_sa_manager {
>  	void				*cpu_ptr;
>  };
>  
> -int amdgpu_fence_slab_init(void);
> -void amdgpu_fence_slab_fini(void);
> -
>  /*
>   * IRQS.
>   */
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 7f8fa69300bf4..d645fa9bdff3b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -3113,10 +3113,6 @@ static int __init amdgpu_init(void)
>  	if (r)
>  		goto error_sync;
>  
> -	r = amdgpu_fence_slab_init();
> -	if (r)
> -		goto error_fence;
> -
>  	r = amdgpu_userq_fence_slab_init();
>  	if (r)
>  		goto error_fence;
> @@ -3151,7 +3147,6 @@ static void __exit amdgpu_exit(void)
>  	amdgpu_unregister_atpx_handler();
>  	amdgpu_acpi_release();
>  	amdgpu_sync_fini();
> -	amdgpu_fence_slab_fini();
>  	amdgpu_userq_fence_slab_fini();
>  	mmu_notifier_synchronize();
>  	amdgpu_xcp_drv_release();
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> index e88848c14491a..5555f3ae08c60 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> @@ -41,21 +41,6 @@
>  #include "amdgpu_trace.h"
>  #include "amdgpu_reset.h"
>  
> -static struct kmem_cache *amdgpu_fence_slab;
> -
> -int amdgpu_fence_slab_init(void)
> -{
> -	amdgpu_fence_slab = KMEM_CACHE(amdgpu_fence, SLAB_HWCACHE_ALIGN);
> -	if (!amdgpu_fence_slab)
> -		return -ENOMEM;
> -	return 0;
> -}
> -
> -void amdgpu_fence_slab_fini(void)
> -{
> -	rcu_barrier();
> -	kmem_cache_destroy(amdgpu_fence_slab);
> -}
>  /*
>   * Cast helper
>   */
> @@ -132,8 +117,8 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
>  
>  	if (!af) {
>  		/* create a separate hw fence */
> -		am_fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_ATOMIC);
> -		if (am_fence == NULL)
> +		am_fence = kmalloc(sizeof(*am_fence), GFP_KERNEL);
> +		if (!am_fence)
>  			return -ENOMEM;
>  	} else {
>  		am_fence = af;
> @@ -806,7 +791,7 @@ static void amdgpu_fence_free(struct rcu_head *rcu)
>  	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
>  
>  	/* free fence_slab if it's separated fence*/
> -	kmem_cache_free(amdgpu_fence_slab, to_amdgpu_fence(f));
> +	kfree(to_amdgpu_fence(f));
>  }
>  
>  /**