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bpf: Skip anonymous types in type lookup for performance

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Currently, vmlinux and kernel module BTFs are unconditionally
sorted during the build phase, with named types placed at the
end. Thus, anonymous types should be skipped when starting the
search. In my vmlinux BTF, the number of anonymous types is
61,747, which means the loop count can be reduced by 61,747.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-9-dolinux.peng@gmail.com
This commit is contained in:
Donglin Peng 2026-01-09 21:00:00 +08:00 committed by Andrii Nakryiko
parent 342bf525ba
commit dc893cfa39
2 changed files with 7 additions and 10 deletions
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10
kernel/bpf/btf.c
View File

@ -3534,7 +3534,8 @@ const char *btf_find_decl_tag_value(const struct btf *btf, const struct btf_type
const struct btf_type *t;
int len, id;
id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key, 0);
id = btf_find_next_decl_tag(btf, pt, comp_idx, tag_key,
btf_named_start_id(btf, false) - 1);
if (id < 0)
return ERR_PTR(id);
@ -7844,12 +7845,13 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
tname);
return -EINVAL;
}
/* Convert BTF function arguments into verifier types.
* Only PTR_TO_CTX and SCALAR are supported atm.
*/
for (i = 0; i < nargs; i++) {
u32 tags = 0;
int id = 0;
int id = btf_named_start_id(btf, false) - 1;
/* 'arg:<tag>' decl_tag takes precedence over derivation of
* register type from BTF type itself
@ -9338,7 +9340,7 @@ bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
}
/* Attempt to find target candidates in vmlinux BTF first */
cands = bpf_core_add_cands(cands, main_btf, 1);
cands = bpf_core_add_cands(cands, main_btf, btf_named_start_id(main_btf, true));
if (IS_ERR(cands))
return ERR_CAST(cands);
@ -9370,7 +9372,7 @@ bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
*/
btf_get(mod_btf);
spin_unlock_bh(&btf_idr_lock);
cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
cands = bpf_core_add_cands(cands, mod_btf, btf_named_start_id(mod_btf, true));
btf_put(mod_btf);
if (IS_ERR(cands))
return ERR_CAST(cands);

7
kernel/bpf/verifier.c
View File

@ -20687,12 +20687,7 @@ static int find_btf_percpu_datasec(struct btf *btf)
* types to look at only module's own BTF types.
*/
n = btf_nr_types(btf);
if (btf_is_module(btf))
i = btf_nr_types(btf_vmlinux);
else
i = 1;
for(; i < n; i++) {
for (i = btf_named_start_id(btf, true); i < n; i++) {
t = btf_type_by_id(btf, i);
if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
continue;