I've made a mistake of looking into lib/kstrtox.o code generation.
The only function remotely performance critical is _parse_integer()
(via /proc/*/map_files/*), everything else is not.
Uninline everything, shrink lib/kstrtox.o by ~20 % !
Space savings on x86_64:
add/remove: 0/0 grow/shrink: 0/23 up/down: 0/-1269 (-1269 !!!)
Function old new delta
kstrtoull 16 13 -3
kstrtouint 59 48 -11
kstrtou8 60 49 -11
kstrtou16 61 50 -11
_kstrtoul 46 35 -11
kstrtoull_from_user 95 83 -12
kstrtoul_from_user 95 83 -12
kstrtoll 93 80 -13
kstrtouint_from_user 124 83 -41
kstrtou8_from_user 125 83 -42
kstrtou16_from_user 126 83 -43
kstrtos8 101 50 -51
kstrtos16 102 51 -51
kstrtoint 100 49 -51
_kstrtol 93 35 -58
kstrtobool_from_user 156 75 -81
kstrtoll_from_user 165 83 -82
kstrtol_from_user 165 83 -82
kstrtoint_from_user 172 83 -89
kstrtos8_from_user 173 83 -90
kstrtos16_from_user 174 83 -91
_parse_integer 136 10 -126
_kstrtoull 308 101 -207
Total: Before=3421236, After=3419967, chg -0.04%
Signed-off-by: Alexey Dobriyan <[email protected]>
---
lib/kstrtox.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -22,6 +22,7 @@
#include "kstrtox.h"
+noinline
const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
{
if (*base == 0) {
@@ -47,6 +48,7 @@ const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
*
* Don't you dare use this function.
*/
+noinline
unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p,
size_t max_chars)
{
@@ -85,6 +87,7 @@ unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned lon
return rv;
}
+noinline
unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)
{
return _parse_integer_limit(s, base, p, INT_MAX);
@@ -125,6 +128,7 @@ static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
* Preferred over simple_strtoull(). Return code must be checked.
*/
+noinline
int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
{
if (s[0] == '+')
@@ -148,6 +152,7 @@ EXPORT_SYMBOL(kstrtoull);
* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
* Preferred over simple_strtoll(). Return code must be checked.
*/
+noinline
int kstrtoll(const char *s, unsigned int base, long long *res)
{
unsigned long long tmp;
@@ -219,6 +224,7 @@ EXPORT_SYMBOL(_kstrtol);
* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
* Preferred over simple_strtoul(). Return code must be checked.
*/
+noinline
int kstrtouint(const char *s, unsigned int base, unsigned int *res)
{
unsigned long long tmp;
@@ -249,6 +255,7 @@ EXPORT_SYMBOL(kstrtouint);
* Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
* Preferred over simple_strtol(). Return code must be checked.
*/
+noinline
int kstrtoint(const char *s, unsigned int base, int *res)
{
long long tmp;
@@ -264,6 +271,7 @@ int kstrtoint(const char *s, unsigned int base, int *res)
}
EXPORT_SYMBOL(kstrtoint);
+noinline
int kstrtou16(const char *s, unsigned int base, u16 *res)
{
unsigned long long tmp;
@@ -279,6 +287,7 @@ int kstrtou16(const char *s, unsigned int base, u16 *res)
}
EXPORT_SYMBOL(kstrtou16);
+noinline
int kstrtos16(const char *s, unsigned int base, s16 *res)
{
long long tmp;
@@ -294,6 +303,7 @@ int kstrtos16(const char *s, unsigned int base, s16 *res)
}
EXPORT_SYMBOL(kstrtos16);
+noinline
int kstrtou8(const char *s, unsigned int base, u8 *res)
{
unsigned long long tmp;
@@ -309,6 +319,7 @@ int kstrtou8(const char *s, unsigned int base, u8 *res)
}
EXPORT_SYMBOL(kstrtou8);
+noinline
int kstrtos8(const char *s, unsigned int base, s8 *res)
{
long long tmp;
@@ -333,6 +344,7 @@ EXPORT_SYMBOL(kstrtos8);
* [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
* pointed to by res is updated upon finding a match.
*/
+noinline
int kstrtobool(const char *s, bool *res)
{
if (!s)