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| author | Peter Zijlstra <peterz@infradead.org> | 2020-03-12 11:32:10 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-03-25 20:28:29 +0300 |
| commit | ae358196fac3a0b4d2a7d47a4f401e3421027b03 (patch) | |
| tree | 183b84e1a566c504bffc71cb65afea6270d96135 /tools/objtool | |
| parent | 530389968739883a61192767e1c215653ba4ba2b (diff) | |
| download | linux-ae358196fac3a0b4d2a7d47a4f401e3421027b03.tar.xz | |
objtool: Optimize find_section_by_name()
In order to avoid yet another linear search of (20k) sections, add a
name based hash.
This reduces objtool runtime on vmlinux.o by some 10s to around 35s.
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/20200324160924.440174280@infradead.org
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/elf.c | 10 | ||||
| -rw-r--r-- | tools/objtool/elf.h | 3 |
2 files changed, 12 insertions, 1 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index 900771365ae3..20fe40d5101d 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -22,11 +22,16 @@ #define MAX_NAME_LEN 128 +static inline u32 str_hash(const char *str) +{ + return jhash(str, strlen(str), 0); +} + struct section *find_section_by_name(struct elf *elf, const char *name) { struct section *sec; - list_for_each_entry(sec, &elf->sections, list) + hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name)) if (!strcmp(sec->name, name)) return sec; @@ -202,6 +207,7 @@ static int read_sections(struct elf *elf) list_add_tail(&sec->list, &elf->sections); hash_add(elf->section_hash, &sec->hash, sec->idx); + hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); } if (stats) @@ -441,6 +447,7 @@ struct elf *elf_read(const char *name, int flags) hash_init(elf->symbol_hash); hash_init(elf->section_hash); + hash_init(elf->section_name_hash); INIT_LIST_HEAD(&elf->sections); elf->fd = open(name, flags); @@ -581,6 +588,7 @@ struct section *elf_create_section(struct elf *elf, const char *name, list_add_tail(&sec->list, &elf->sections); hash_add(elf->section_hash, &sec->hash, sec->idx); + hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name)); return sec; } diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h index 8c272eb515c8..ac7c46f7d9ab 100644 --- a/tools/objtool/elf.h +++ b/tools/objtool/elf.h @@ -10,6 +10,7 @@ #include <gelf.h> #include <linux/list.h> #include <linux/hashtable.h> +#include <linux/jhash.h> #ifdef LIBELF_USE_DEPRECATED # define elf_getshdrnum elf_getshnum @@ -26,6 +27,7 @@ struct section { struct list_head list; struct hlist_node hash; + struct hlist_node name_hash; GElf_Shdr sh; struct list_head symbol_list; struct list_head rela_list; @@ -73,6 +75,7 @@ struct elf { struct list_head sections; DECLARE_HASHTABLE(symbol_hash, 20); DECLARE_HASHTABLE(section_hash, 16); + DECLARE_HASHTABLE(section_name_hash, 16); }; |