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authorJosh Poimboeuf <jpoimboe@kernel.org>2023-05-30 10:21:14 -0700
committerJosh Poimboeuf <jpoimboe@kernel.org>2023-06-07 10:03:27 -0700
commitb4c96ef0add5b701eb37be9830a98610e1d9b4a3 (patch)
tree7ab7519c4077033a7568c3f16509fb6c5e9f2dca
parentd93b5935fd47007597aed5105a902a10204bc30e (diff)
objtool: Skip reading DWARF section data
Objtool doesn't use DWARF at all, and the DWARF sections' data take up a lot of memory. Skip reading them. Note this only skips the DWARF base sections, not the rela sections. The relas are needed because their symbol references may need to be reindexed if any local symbols get added by elf_create_symbol(). Also note the DWARF data will eventually be read by libelf anyway, when writing the object file. But that's fine, the goal here is to reduce *peak* memory usage, and the previous patch (which freed insn memory) gave some breathing room. So the allocation gets shifted to a later time, resulting in lower peak memory usage. With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 29.93G - After: peak heap memory consumption: 25.47G Link: https://lore.kernel.org/r/52a9698835861dd35f2ec35c49f96d0bb39fb177.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
-rw-r--r--tools/objtool/elf.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 54d182ddc4bb..d420b5d2e2b6 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -300,6 +300,11 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns
return find_reloc_by_dest_range(elf, sec, offset, 1);
}
+static bool is_dwarf_section(struct section *sec)
+{
+ return !strncmp(sec->name, ".debug_", 7);
+}
+
static int read_sections(struct elf *elf)
{
Elf_Scn *s = NULL;
@@ -350,7 +355,7 @@ static int read_sections(struct elf *elf)
return -1;
}
- if (sec->sh.sh_size != 0) {
+ if (sec->sh.sh_size != 0 && !is_dwarf_section(sec)) {
sec->data = elf_getdata(s, NULL);
if (!sec->data) {
WARN_ELF("elf_getdata");