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Code Issues Releases Wiki Activity

objtool: Optimize find_symbol_by_name()

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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
This commit is contained in:
Peter Zijlstra 2020-03-12 10:17:38 +01:00
parent 513b5ca6b5
commit cdb3d057a1
2 changed files with 7 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
tools/objtool/elf.c
View file

@ -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);

2
tools/objtool/elf.h
View file

@ -47,6 +47,7 @@ struct symbol {
struct list_head list;
struct rb_node node;
struct hlist_node hash;
struct hlist_node name_hash;
GElf_Sym sym;
struct section *sec;
char *name;
@ -77,6 +78,7 @@ struct elf {
char *name;
struct list_head sections;
DECLARE_HASHTABLE(symbol_hash, 20);
DECLARE_HASHTABLE(symbol_name_hash, 20);
DECLARE_HASHTABLE(section_hash, 16);
DECLARE_HASHTABLE(section_name_hash, 16);
};