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authorPeter Zijlstra <peterz@infradead.org>2020-03-12 11:23:36 +0100
committerPeter Zijlstra <peterz@infradead.org>2020-03-25 18:28:30 +0100
commit8b5fa6bc326bf02f293b5a39a8f5b3de816265d3 (patch)
tree11121ed0c5015841e16a84207a1bf80a31f09dfb /tools/objtool/elf.c
parentcdb3d057a17d56363a831e486ea39e4c389a6cf9 (diff)
downloadlinux-8b5fa6bc326bf02f293b5a39a8f5b3de816265d3.tar.bz2
objtool: Optimize read_sections()
Perf showed that __hash_init() is a significant portion of read_sections(), so instead of doing a per section rela_hash, use an elf-wide rela_hash. Statistics show us there are about 1.1 million relas, so size it accordingly. This reduces the objtool on vmlinux.o runtime to a third, from 15 to 5 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/20200324160924.739153726@infradead.org
Diffstat (limited to 'tools/objtool/elf.c')
-rw-r--r--tools/objtool/elf.c24
1 files changed, 14 insertions, 10 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 43abae763b3b..8a0a1bc18cd7 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -212,8 +212,8 @@ struct symbol *find_symbol_by_name(struct elf *elf, const char *name)
return NULL;
}
-struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
- unsigned int len)
+struct rela *find_rela_by_dest_range(struct elf *elf, struct section *sec,
+ unsigned long offset, unsigned int len)
{
struct rela *rela;
unsigned long o;
@@ -221,17 +221,22 @@ struct rela *find_rela_by_dest_range(struct section *sec, unsigned long offset,
if (!sec->rela)
return NULL;
- for (o = offset; o < offset + len; o++)
- hash_for_each_possible(sec->rela->rela_hash, rela, hash, o)
- if (rela->offset == o)
+ sec = sec->rela;
+
+ for (o = offset; o < offset + len; o++) {
+ hash_for_each_possible(elf->rela_hash, rela, hash,
+ sec_offset_hash(sec, o)) {
+ if (rela->sec == sec && rela->offset == o)
return rela;
+ }
+ }
return NULL;
}
-struct rela *find_rela_by_dest(struct section *sec, unsigned long offset)
+struct rela *find_rela_by_dest(struct elf *elf, struct section *sec, unsigned long offset)
{
- return find_rela_by_dest_range(sec, offset, 1);
+ return find_rela_by_dest_range(elf, sec, offset, 1);
}
static int read_sections(struct elf *elf)
@@ -261,7 +266,6 @@ static int read_sections(struct elf *elf)
INIT_LIST_HEAD(&sec->symbol_list);
INIT_LIST_HEAD(&sec->rela_list);
- hash_init(sec->rela_hash);
s = elf_getscn(elf->elf, i);
if (!s) {
@@ -493,7 +497,7 @@ static int read_relas(struct elf *elf)
}
list_add_tail(&rela->list, &sec->rela_list);
- hash_add(sec->rela_hash, &rela->hash, rela->offset);
+ hash_add(elf->rela_hash, &rela->hash, rela_hash(rela));
nr_rela++;
}
max_rela = max(max_rela, nr_rela);
@@ -526,6 +530,7 @@ struct elf *elf_read(const char *name, int flags)
hash_init(elf->symbol_name_hash);
hash_init(elf->section_hash);
hash_init(elf->section_name_hash);
+ hash_init(elf->rela_hash);
INIT_LIST_HEAD(&elf->sections);
elf->fd = open(name, flags);
@@ -586,7 +591,6 @@ struct section *elf_create_section(struct elf *elf, const char *name,
INIT_LIST_HEAD(&sec->symbol_list);
INIT_LIST_HEAD(&sec->rela_list);
- hash_init(sec->rela_hash);
s = elf_newscn(elf->elf);
if (!s) {