objtool: Shrink elf hash nodes

Instead of using hlist for the 'struct elf' hashes, use a custom
single-linked list scheme.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 36.89G
- After:  peak heap memory consumption: 35.12G

Link: https://lore.kernel.org/r/6e8cd305ed22e743c30d6e72cfdc1be20fb94cd4.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

1 files changed, 14 insertions, 10 deletions

diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 7b808ac3156c..03a9040f696c 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -26,10 +26,14 @@
 #define ELF_C_READ_MMAP ELF_C_READ
 #endif
 
+struct elf_hash_node {
+	struct elf_hash_node *next;
+};
+
 struct section {
 	struct list_head list;
-	struct hlist_node hash;
-	struct hlist_node name_hash;
+	struct elf_hash_node hash;
+	struct elf_hash_node name_hash;
 	GElf_Shdr sh;
 	struct rb_root_cached symbol_tree;
 	struct list_head symbol_list;
@@ -45,8 +49,8 @@ struct section {
 struct symbol {
 	struct list_head list;
 	struct rb_node node;
-	struct hlist_node hash;
-	struct hlist_node name_hash;
+	struct elf_hash_node hash;
+	struct elf_hash_node name_hash;
 	GElf_Sym sym;
 	struct section *sec;
 	char *name;
@@ -67,7 +71,7 @@ struct symbol {
 };
 
 struct reloc {
-	struct hlist_node hash;
+	struct elf_hash_node hash;
 	union {
 		GElf_Rela rela;
 		GElf_Rel  rel;
@@ -93,11 +97,11 @@ struct elf {
 	int section_name_bits;
 	int reloc_bits;
 
-	struct hlist_head *symbol_hash;
-	struct hlist_head *symbol_name_hash;
-	struct hlist_head *section_hash;
-	struct hlist_head *section_name_hash;
-	struct hlist_head *reloc_hash;
+	struct elf_hash_node **symbol_hash;
+	struct elf_hash_node **symbol_name_hash;
+	struct elf_hash_node **section_hash;
+	struct elf_hash_node **section_name_hash;
+	struct elf_hash_node **reloc_hash;
 
 	struct section *section_data;
 	struct symbol *symbol_data;