Supplement: The two types of memory in ACL make a management strategy
unnecessary: (1) the run-time memory for the match tree, which is
allocated as a single block during each build and freed when the ACL is
reset; and (2) the temporary memory used during the build process, which
is allocated multiple times within a single build and then released all
at once after the build is finished.
On 12/11/2025 9:46 AM, Stephen Hemminger wrote:
On Tue, 25 Nov 2025 12:14:46 +0000
"mannywang(王永峰)" <[email protected]> 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.
Signed-off-by: YongFeng Wang <[email protected]>
---
Rather than custom allocators, I did a couple of quick AI queries about
alternatives. It looks like there are some big global gains possible
here:
Summary of Recommendations
Improvement Benefit Complexity Priority
ACL Object Pooling Eliminates ACL-specific fragmentation Medium High
Size-Class Segregation Reduces general fragmentation High High
Slab Allocator for Build Better hugepage utilization Medium Medium
Deferred Coalescing Reduces fragmentation from churn Medium Medium
Thread-Local Caching Reduces contention, improves locality Medium Medium
Also adding some malloc_trim() would help.
https://claude.ai/share/75fcf73c-17e3-4f41-8590-f2ab640f9512
