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Message-Id: <20251117132623.3807094-7-dolinux.peng@gmail.com>
Date: Mon, 17 Nov 2025 21:26:22 +0800
From: Donglin Peng <dolinux.peng@...il.com>
To: ast@...nel.org
Cc: eddyz87@...il.com,
andrii.nakryiko@...il.com,
zhangxiaoqin@...omi.com,
linux-kernel@...r.kernel.org,
bpf@...r.kernel.org,
Donglin Peng <pengdonglin@...omi.com>,
Alan Maguire <alan.maguire@...cle.com>,
Song Liu <song@...nel.org>
Subject: [RFC PATCH v6 6/7] btf: Optimize type lookup with binary search
From: Donglin Peng <pengdonglin@...omi.com>
Improve btf_find_by_name_kind() performance by adding binary search
support for sorted types. Falls back to linear search for compatibility.
Cc: Eduard Zingerman <eddyz87@...il.com>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc: Alan Maguire <alan.maguire@...cle.com>
Cc: Song Liu <song@...nel.org>
Cc: Xiaoqin Zhang <zhangxiaoqin@...omi.com>
Signed-off-by: Donglin Peng <pengdonglin@...omi.com>
---
kernel/bpf/btf.c | 83 ++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 73 insertions(+), 10 deletions(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 0de8fc8a0e0b..5dd2c40d4874 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -259,6 +259,7 @@ struct btf {
void *nohdr_data;
struct btf_header hdr;
u32 nr_types; /* includes VOID for base BTF */
+ u32 nr_sorted_types; /* exclude VOID for base BTF */
u32 types_size;
u32 data_size;
refcount_t refcnt;
@@ -494,6 +495,11 @@ static bool btf_type_is_modifier(const struct btf_type *t)
return false;
}
+static int btf_start_id(const struct btf *btf)
+{
+ return btf->start_id + (btf->base_btf ? 0 : 1);
+}
+
bool btf_type_is_void(const struct btf_type *t)
{
return t == &btf_void;
@@ -544,24 +550,78 @@ u32 btf_nr_types(const struct btf *btf)
return total;
}
+static s32 btf_find_by_name_kind_bsearch(const struct btf *btf, const char *name,
+ s32 start_id, s32 end_id)
+{
+ const struct btf_type *t;
+ const char *tname;
+ s32 l, r, m;
+
+ l = start_id;
+ r = end_id;
+ while (l <= r) {
+ m = l + (r - l) / 2;
+ t = btf_type_by_id(btf, m);
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (strcmp(tname, name) >= 0) {
+ if (l == r)
+ return r;
+ r = m;
+ } else {
+ l = m + 1;
+ }
+ }
+
+ return btf_nr_types(btf);
+}
+
s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
{
+ const struct btf *base_btf = btf_base_btf(btf);
const struct btf_type *t;
const char *tname;
- u32 i, total;
+ int err = -ENOENT;
- total = btf_nr_types(btf);
- for (i = 1; i < total; i++) {
- t = btf_type_by_id(btf, i);
- if (BTF_INFO_KIND(t->info) != kind)
- continue;
+ if (base_btf) {
+ err = btf_find_by_name_kind(base_btf, name, kind);
+ if (err > 0)
+ goto out;
+ }
- tname = btf_name_by_offset(btf, t->name_off);
- if (!strcmp(tname, name))
- return i;
+ if (btf->nr_sorted_types > 0) {
+ /* binary search */
+ s32 start_id, end_id;
+ u32 idx;
+
+ start_id = btf_start_id(btf);
+ end_id = start_id + btf->nr_sorted_types - 1;
+ idx = btf_find_by_name_kind_bsearch(btf, name, start_id, end_id);
+ for (; idx <= end_id; idx++) {
+ t = btf_type_by_id(btf, idx);
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (strcmp(tname, name))
+ goto out;
+ if (BTF_INFO_KIND(t->info) == kind)
+ return idx;
+ }
+ } else {
+ /* linear search */
+ u32 i, total;
+
+ total = btf_nr_types(btf);
+ for (i = btf_start_id(btf); i < total; i++) {
+ t = btf_type_by_id(btf, i);
+ if (BTF_INFO_KIND(t->info) != kind)
+ continue;
+
+ tname = btf_name_by_offset(btf, t->name_off);
+ if (!strcmp(tname, name))
+ return i;
+ }
}
- return -ENOENT;
+out:
+ return err;
}
s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
@@ -5791,6 +5851,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
goto errout;
}
env->btf = btf;
+ btf->nr_sorted_types = 0;
data = kvmalloc(attr->btf_size, GFP_KERNEL | __GFP_NOWARN);
if (!data) {
@@ -6210,6 +6271,7 @@ static struct btf *btf_parse_base(struct btf_verifier_env *env, const char *name
btf->data = data;
btf->data_size = data_size;
btf->kernel_btf = true;
+ btf->nr_sorted_types = 0;
snprintf(btf->name, sizeof(btf->name), "%s", name);
err = btf_parse_hdr(env);
@@ -6327,6 +6389,7 @@ static struct btf *btf_parse_module(const char *module_name, const void *data,
btf->start_id = base_btf->nr_types;
btf->start_str_off = base_btf->hdr.str_len;
btf->kernel_btf = true;
+ btf->nr_sorted_types = 0;
snprintf(btf->name, sizeof(btf->name), "%s", module_name);
btf->data = kvmemdup(data, data_size, GFP_KERNEL | __GFP_NOWARN);
--
2.34.1
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