Significantly Improve BTF Type Lookup Performance

include/linux/btf.h

@@ -220,7 +220,11 @@ bool btf_is_module(const struct btf *btf);
 bool btf_is_vmlinux(const struct btf *btf);
 struct module *btf_try_get_module(const struct btf *btf);
 u32 btf_nr_types(const struct btf *btf);
-struct btf *btf_base_btf(const struct btf *btf);
+u32 btf_type_cnt(const struct btf *btf);
+u32 btf_start_id(const struct btf *btf);
+u32 btf_nr_sorted_types(const struct btf *btf);
+void btf_set_nr_sorted_types(struct btf *btf, u32 nr);
+struct btf* btf_base_btf(const struct btf *btf);
 bool btf_type_is_i32(const struct btf_type *t);
 bool btf_type_is_i64(const struct btf_type *t);
 bool btf_type_is_primitive(const struct btf_type *t);
@@ -594,6 +598,10 @@ int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_ty
 bool btf_types_are_same(const struct btf *btf1, u32 id1,
 			const struct btf *btf2, u32 id2);
 int btf_check_iter_arg(struct btf *btf, const struct btf_type *func, int arg_idx);
+int btf_compare_type_kinds_names(const void *a, const void *b, void *priv);
+s32 find_btf_by_name_kind(const struct btf *btf, int start_id, const char *type_name,
+			  u32 kind);
+void btf_check_sorted(struct btf *btf, int start_id);
 
 static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
 {
@@ -682,5 +690,16 @@ static inline int btf_check_iter_arg(struct btf *btf, const struct btf_type *fun
 {
 	return -EOPNOTSUPP;
 }
+static inline int btf_compare_type_kinds_names(const void *a, const void *b, void *priv)
+{
+	return -EOPNOTSUPP;
+}
+static inline s32 find_btf_by_name_kind(const struct btf *btf, int start_id, const char *type_name,
+			  u32 kind)
+{
+	return -EOPNOTSUPP;
+}
+static inline void btf_check_sorted(struct btf *btf, int start_id);
+{}
 #endif
 #endif

kernel/bpf/Kconfig

@@ -101,4 +101,12 @@ config BPF_LSM
 
 	  If you are unsure how to answer this question, answer N.
 
+config BPF_SORT_BTF_BY_KIND_NAME
+	bool "Sort BTF types by kind and name"
+	depends on BPF_SYSCALL
+	help
+	  This option sorts BTF types in vmlinux and kernel modules by their
+	  kind and name, enabling binary search for btf_find_by_name_kind()
+	  and significantly improving its lookup performance.
+
 endmenu # "BPF subsystem"

kernel/bpf/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_BPF_SYSCALL) += kmem_cache_iter.o
 ifeq ($(CONFIG_DMA_SHARED_BUFFER),y)
 obj-$(CONFIG_BPF_SYSCALL) += dmabuf_iter.o
 endif
+obj-$(CONFIG_BPF_SYSCALL) += btf_sort.o
 
 CFLAGS_REMOVE_percpu_freelist.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_bpf_lru_list.o = $(CC_FLAGS_FTRACE)

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;
 	u32 types_size;
 	u32 data_size;
 	refcount_t refcnt;
@@ -544,24 +545,29 @@ u32 btf_nr_types(const struct btf *btf)
 	return total;
 }
 
-s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
+u32 btf_start_id(const struct btf *btf)
 {
-	const struct btf_type *t;
-	const char *tname;
-	u32 i, total;
+	return btf->start_id;
+}
 
-	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;
+u32 btf_nr_sorted_types(const struct btf *btf)
+{
+	return btf->nr_sorted_types;
+}
 
-		tname = btf_name_by_offset(btf, t->name_off);
-		if (!strcmp(tname, name))
-			return i;
-	}
+void btf_set_nr_sorted_types(struct btf *btf, u32 nr)
+{
+	btf->nr_sorted_types = nr;
+}
 
-	return -ENOENT;
+u32 btf_type_cnt(const struct btf *btf)
+{
+	return btf->start_id + btf->nr_types;
+}
+
+s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
+{
+	return find_btf_by_name_kind(btf, 1, name, kind);
 }
 
 s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
@@ -6230,6 +6236,7 @@ static struct btf *btf_parse_base(struct btf_verifier_env *env, const char *name
 	if (err)
 		goto errout;
 
+	btf_check_sorted(btf, 1);
 	refcount_set(&btf->refcnt, 1);
 
 	return btf;
@@ -6362,6 +6369,7 @@ static struct btf *btf_parse_module(const char *module_name, const void *data,
 		base_btf = vmlinux_btf;
 	}
 
+	btf_check_sorted(btf, btf_nr_types(base_btf));
 	btf_verifier_env_free(env);
 	refcount_set(&btf->refcnt, 1);
 	return btf;

kernel/bpf/btf_sort.c

@@ -0,0 +1,2 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+#include "../../tools/lib/bpf/btf_sort.c"

scripts/Makefile.btf

@@ -29,6 +29,11 @@ ifneq ($(KBUILD_EXTMOD),)
 module-pahole-flags-$(call test-ge, $(pahole-ver), 128) += --btf_features=distilled_base
 endif
 
+ifeq ($(call test-ge, $(pahole-ver), 132),y)
+pahole-flags-$(CONFIG_BPF_SORT_BTF_BY_KIND_NAME) 	+= --btf_features=sort
+module-pahole-flags-$(CONFIG_BPF_SORT_BTF_BY_KIND_NAME) += --btf_features=sort
+endif
+
 endif
 
 pahole-flags-$(CONFIG_PAHOLE_HAS_LANG_EXCLUDE)		+= --lang_exclude=rust

tools/lib/bpf/Build

@@ -1,4 +1,4 @@
 libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_utils.o \
 	    netlink.o bpf_prog_linfo.o libbpf_probes.o hashmap.o \
 	    btf_dump.o ringbuf.o strset.o linker.o gen_loader.o relo_core.o \
-	    usdt.o zip.o elf.o features.o btf_iter.o btf_relocate.o
+	    usdt.o zip.o elf.o features.o btf_iter.o btf_relocate.o btf_sort.o