Hi,
On 11/18/2024 9:29 PM, Thomas Weißschuh wrote:
> 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();
Indeed. Thanks for the suggestion. Will do in v2.
>> +}
>> --
>> 2.29.2
>>
