On Mon, Nov 18, 2024 at 09:08:04AM +0800, Hou Tao wrote:
> From: Hou Tao <houtao1@xxxxxxxxxx>
>
> Add bpf_mem_cache_is_mergeable() to check whether two bpf mem allocator
> for fixed-size objects are mergeable or not. The merging could reduce
> the memory overhead of bpf mem allocator.
>
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> include/linux/bpf_mem_alloc.h | 1 +
> kernel/bpf/memalloc.c | 12 ++++++++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/include/linux/bpf_mem_alloc.h b/include/linux/bpf_mem_alloc.h
> index e45162ef59bb..faa54b9c7a04 100644
> --- a/include/linux/bpf_mem_alloc.h
> +++ b/include/linux/bpf_mem_alloc.h
> @@ -47,5 +47,6 @@ void bpf_mem_cache_free(struct bpf_mem_alloc *ma, void *ptr);
> void bpf_mem_cache_free_rcu(struct bpf_mem_alloc *ma, void *ptr);
> void bpf_mem_cache_raw_free(void *ptr);
> void *bpf_mem_cache_alloc_flags(struct bpf_mem_alloc *ma, gfp_t flags);
> +bool bpf_mem_cache_is_mergeable(size_t size, size_t new_size, bool percpu);
>
> #endif /* _BPF_MEM_ALLOC_H */
> diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
> index 889374722d0a..49dd08ad1d4f 100644
> --- a/kernel/bpf/memalloc.c
> +++ b/kernel/bpf/memalloc.c
> @@ -1014,3 +1014,15 @@ int bpf_mem_alloc_check_size(bool percpu, size_t size)
>
> return 0;
> }
> +
> +bool bpf_mem_cache_is_mergeable(size_t size, size_t new_size, bool percpu)
> +{
> + /* Only for fixed-size object allocator */
> + if (!size || !new_size)
> + return false;
> +
> + return (percpu && ALIGN(size, PCPU_MIN_ALLOC_SIZE) ==
> + ALIGN(new_size, PCPU_MIN_ALLOC_SIZE)) ||
> + (!percpu && kmalloc_size_roundup(size + LLIST_NODE_SZ) ==
> + kmalloc_size_roundup(new_size + LLIST_NODE_SZ));
This would be easier to read:
if (percpu)
return ALIGN() == ALIGN();
else
return kmalloc_size_roundup() == kmalloc_size_roundup();
> +}
> --
> 2.29.2
>
