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authorPeter Zijlstra <peterz@infradead.org>2020-03-12 10:17:38 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-03-25 18:28:30 +0100
commitcdb3d057a17d56363a831e486ea39e4c389a6cf9 (patch)
tree87c68d4378ff885e3efaba3cbad947f100c1c071 /tools/objtool/elf.c
parent513b5ca6b5fbeb766999fb1a4bc9a55c9fb7c9ca (diff)
downloadlinux-cdb3d057a17d56363a831e486ea39e4c389a6cf9.tar.gz
objtool: Optimize find_symbol_by_name()
Perf showed that find_symbol_by_name() takes time; add a symbol name
hash.

This shaves another second off of objtool on vmlinux.o runtime, down
to 15 seconds.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200324160924.676865656@infradead.org
Diffstat (limited to 'tools/objtool/elf.c')
-rw-r--r--tools/objtool/elf.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 07db4df18588..43abae763b3b 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -203,13 +203,11 @@ struct symbol *find_func_containing(struct section *sec, unsigned long offset)
 
 struct symbol *find_symbol_by_name(struct elf *elf, const char *name)
 {
-	struct section *sec;
 	struct symbol *sym;
 
-	list_for_each_entry(sec, &elf->sections, list)
-		list_for_each_entry(sym, &sec->symbol_list, list)
-			if (!strcmp(sym->name, name))
-				return sym;
+	hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name))
+		if (!strcmp(sym->name, name))
+			return sym;
 
 	return NULL;
 }
@@ -386,6 +384,7 @@ static int read_symbols(struct elf *elf)
 			entry = &sym->sec->symbol_list;
 		list_add(&sym->list, entry);
 		hash_add(elf->symbol_hash, &sym->hash, sym->idx);
+		hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name));
 	}
 
 	if (stats)
@@ -524,6 +523,7 @@ struct elf *elf_read(const char *name, int flags)
 	memset(elf, 0, sizeof(*elf));
 
 	hash_init(elf->symbol_hash);
+	hash_init(elf->symbol_name_hash);
 	hash_init(elf->section_hash);
 	hash_init(elf->section_name_hash);
 	INIT_LIST_HEAD(&elf->sections);