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| author | Mykyta Yatsenko <yatsenko@meta.com> | 2026-06-05 04:41:21 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-05 08:00:08 -0700 |
| commit | 16b4d3e2fb24aac3e68a8d86e3bc5e302e1b5cb7 (patch) | |
| tree | 91b75325f2d9674e614362f2b997230783b959fe /kernel/bpf/syscall.c | |
| parent | 46730ee6e884be667365e4d3a380ac504697559a (diff) | |
| download | lwn-16b4d3e2fb24aac3e68a8d86e3bc5e302e1b5cb7.tar.gz lwn-16b4d3e2fb24aac3e68a8d86e3bc5e302e1b5cb7.zip | |
bpf: Implement resizable hashmap basic functions
Use rhashtable_lookup_likely() for lookups, rhashtable_remove_fast()
for deletes, and rhashtable_lookup_get_insert_fast() for inserts.
Updates modify values in place under RCU rather than allocating a
new element and swapping the pointer (as regular htab does). This
trades read consistency for performance: concurrent readers may
see partial updates. BPF_F_LOCK support and special-field
handling (timers, kptrs, etc.) follow in a later commit.
Initialize rhashtable with bpf_mem_alloc element cache. Require
BPF_F_NO_PREALLOC. Limit max_entries to 2^31. Free elements via
rhashtable_free_and_destroy().
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260605-rhash-v7-4-5b8e05f8630d@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/syscall.c')
| -rw-r--r-- | kernel/bpf/syscall.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 625a4366fe6d..1faae184de48 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1398,6 +1398,7 @@ static int map_create_alloc(union bpf_attr *attr, bpfptr_t uattr, struct bpf_ver if (attr->map_type != BPF_MAP_TYPE_BLOOM_FILTER && attr->map_type != BPF_MAP_TYPE_ARENA && + attr->map_type != BPF_MAP_TYPE_RHASH && attr->map_extra != 0) { bpf_log(log, "Invalid map_extra.\n"); return -EINVAL; @@ -1469,6 +1470,7 @@ static int map_create_alloc(union bpf_attr *attr, bpfptr_t uattr, struct bpf_ver case BPF_MAP_TYPE_CGROUP_ARRAY: case BPF_MAP_TYPE_ARRAY_OF_MAPS: case BPF_MAP_TYPE_HASH: + case BPF_MAP_TYPE_RHASH: case BPF_MAP_TYPE_PERCPU_HASH: case BPF_MAP_TYPE_HASH_OF_MAPS: case BPF_MAP_TYPE_RINGBUF: @@ -2259,6 +2261,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_RHASH || map->map_type == BPF_MAP_TYPE_STACK_TRACE) { if (!bpf_map_is_offloaded(map)) { bpf_disable_instrumentation(); |