[PATCH] do not save thousands of useless symbols in KALLSYMS kernels

[Denis Vlasenko <vda@ilport.com.ua>]

Sample of my kernel's mostly useless symbols
(starting_with:# of symbols):

__func__: 624
__vendorstr_: 1760
__pci_fixup_PCI_: 116
__ksymtab_: 2597
__kstrtab_: 2597
__kcrctab_: 2597
__initcall_: 236
__devicestr_: 4686
__devices_: 1760
Total: 16973
Lines in System.map: 39735

Excluding them from in-kernel symbol table saves ~300kb:

   text    data     bss     dec     hex filename
4337710 1054414  259296 5651420  563bdc vmlinux.carrier1 - w/o KALLSYMS
4342068 1296046  259296 5897410  59fcc2 vmlinux - with KALLSYMS+patch
4341948 1607634  259296 6208878  5ebd6e vmlinux.carrier - with KALLSYMS
        ^^^^^^^
--
vda

--- linux-2.6.12.org/scripts/kallsyms.c.org	Sun Jun 19 16:11:06 2005
+++ linux-2.6.12.org/scripts/kallsyms.c	Wed Aug 10 23:52:06 2005
@@ -36,7 +36,7 @@
 
 /* we use only a subset of the complete symbol table to gather the token count,
  * to speed up compression, at the expense of a little compression ratio */
-#define WORKING_SET		1024
+#define WORKING_SET		(1024*4)
 
 /* first find the best token only on the list of tokens that would profit more
  * than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list.
@@ -102,11 +102,34 @@ usage(void)
  * This ignores the intensely annoying "mapping symbols" found
  * in ARM ELF files: $a, $t and $d.
  */
+/*
+__func__: 624
+__vendorstr_: 1760
+__pci_fixup_PCI_: 116
+__ksymtab_: 2597
+__kstrtab_: 2597
+__kcrctab_: 2597
+__initcall_: 236
+__devicestr_: 4686
+__devices_: 1760
+Total: 16973
+Lines in System.map: 39735
+*/
 static inline int
 is_arm_mapping_symbol(const char *str)
 {
-	return str[0] == '$' && strchr("atd", str[1])
-	       && (str[2] == '\0' || str[2] == '.');
+	return (str[0] == '$' && strchr("atd", str[1])
+	       && (str[2] == '\0' || str[2] == '.')
+	)
+	|| (0 == strncmp(str, "__ksymtab_", sizeof("__ksymtab_")-1))
+	|| (0 == strncmp(str, "__kstrtab_", sizeof("__kstrtab_")-1))
+	|| (0 == strncmp(str, "__kcrctab_", sizeof("__kcrctab_")-1))
+	|| (0 == strncmp(str, "__devices_", sizeof("__devices_")-1))
+	|| (0 == strncmp(str, "__devicestr_", sizeof("__devicestr_")-1))
+	|| (0 == strncmp(str, "__vendorstr_", sizeof("__vendorstr_")-1))
+	|| (0 == strncmp(str, "__pci_fixup_PCI_", sizeof("__pci_fixup_PCI_")-1))
+	|| (0 == strncmp(str, "__func__", sizeof("__func__")-1))
+	;
 }
 
 static int