bpf: Add percpu allocation support to bpf_mem_alloc.

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Extend bpf_mem_alloc to cache free list of fixed size per-cpu allocations.
Once such cache is created bpf_mem_cache_alloc() will return per-cpu objects.
bpf_mem_cache_free() will free them back into global per-cpu pool after
observing RCU grace period.
per-cpu flavor of bpf_mem_alloc is going to be used by per-cpu hash maps.

The free list cache consists of tuples { llist_node, per-cpu pointer }
Unlike alloc_percpu() that returns per-cpu pointer
the bpf_mem_cache_alloc() returns a pointer to per-cpu pointer and
bpf_mem_cache_free() expects to receive it back.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-11-alexei.starovoitov@gmail.com

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Alexei Starovoitov 2022-09-02 14:10:52 -07:00 • committed by Daniel Borkmann

parent 8d5a8011b3

commit 4ab67149f3

3 changed files with 41 additions and 7 deletions

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2

include/linux/bpf_mem_alloc.h

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2

kernel/bpf/hashtab.c

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44

kernel/bpf/memalloc.c

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