diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2022-09-02 14:10:49 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2022-09-05 15:33:06 +0200 |
| commit | 0fd7c5d43339b783ee3301a05f925d1e52ac87c9 (patch) | |
| tree | b19c7f9b83221183677889fd7644b11549453de3 /kernel/bpf/hashtab.c | |
| parent | 86fe28f7692d96d20232af0fc6d7632d5cc89a01 (diff) | |
bpf: Optimize call_rcu in non-preallocated hash map.
Doing call_rcu() million times a second becomes a bottle neck.
Convert non-preallocated hash map from call_rcu to SLAB_TYPESAFE_BY_RCU.
The rcu critical section is no longer observed for one htab element
which makes non-preallocated hash map behave just like preallocated hash map.
The map elements are released back to kernel memory after observing
rcu critical section.
This improves 'map_perf_test 4' performance from 100k events per second
to 250k events per second.
bpf_mem_alloc + percpu_counter + typesafe_by_rcu provide 10x performance
boost to non-preallocated hash map and make it within few % of preallocated map
while consuming fraction of memory.
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/20220902211058.60789-8-alexei.starovoitov@gmail.com
Diffstat (limited to 'kernel/bpf/hashtab.c')
| -rw-r--r-- | kernel/bpf/hashtab.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 36aa16dc43ad..0d888a90a805 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -953,8 +953,12 @@ static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l) __pcpu_freelist_push(&htab->freelist, &l->fnode); } else { dec_elem_count(htab); - l->htab = htab; - call_rcu(&l->rcu, htab_elem_free_rcu); + if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) { + l->htab = htab; + call_rcu(&l->rcu, htab_elem_free_rcu); + } else { + htab_elem_free(htab, l); + } } } |