Re: [PATCH v3] acl: support custom memory allocator

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

On 11/25/25 15:14, mannywang(王永峰) wrote:
> Reduce memory fragmentation caused by dynamic memory allocations
> by allowing users to provide custom memory allocator.
>
> Add new members to struct rte_acl_config to allow passing custom
> allocator callbacks to rte_acl_build:
>
> - running_alloc: allocator callback for run-time internal memory
> - running_free: free callback for run-time internal memory
> - running_ctx: user-defined context passed to running_alloc/free
>
> - temp_alloc: allocator callback for temporary memory during ACL build
> - temp_reset: reset callback for temporary allocator
> - temp_ctx: user-defined context passed to temp_alloc/reset
>
> These callbacks allow users to provide their own memory pools or
> allocators for both persistent runtime structures and temporary
> build-time data.
>
> A typical approach is to pre-allocate a static memory region
> for rte_acl_ctx, and to provide a global temporary memory manager
> that supports multipleallocations and a single reset during ACL build.
>
> Since tb_mem_pool handles allocation failures using siglongjmp,
> temp_alloc follows the same approach for failure handling.

If a static memory region would suffice for runtime memory,
could you have solved the issue using existing API as follows?
1. Allocate memory in any way, may even use `rte_malloc_*()`.
2. Create a new heap using `rte_malloc_heap_create()`.
3. Attach the memory to the heap using `rte_malloc_heap_memory_add()`.
4. Get the heap "socket ID" using `rte_malloc_heap_get_socket()`.
5. Pass the heap "socket ID" to `rte_acl_create()`.

In https://inbox.dpdk.org/dev/tencent_4125B1322F9238892BFA5F38@qq.com/
you said that the issue is runtime memory fragmentation,
but also did "propose extending the ACL API to support
external memory buffers for the build process".
What is the issue with build-time allocations?