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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2021-06-30 18:56:04 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-01 11:06:05 -0700 |
| commit | ad65dcef3a87c24d6c6156eae5e7b47311d6e3cf (patch) | |
| tree | ae1fbd368809d911dfd43f38ecd9a38fabb62fe8 /lib/vsprintf.c | |
| parent | 1a58be6277e4324c853babfd35890c2d5e171e8f (diff) | |
| download | lwn-ad65dcef3a87c24d6c6156eae5e7b47311d6e3cf.tar.gz lwn-ad65dcef3a87c24d6c6156eae5e7b47311d6e3cf.zip | |
lib: uninline simple_strtoull()
Gcc inlines simple_strtoull() too agressively.
Given that all 4 signatures match, everything very efficiently calls or
tailcalls into simple_strtoull():
ffffffff81da0240 <simple_strtoll>:
ffffffff81da0240: 80 3f 2d cmp BYTE PTR [rdi],0x2d
ffffffff81da0243: 74 05 je ffffffff81da024a <simple_strtoll+0xa>
ffffffff81da0245: e9 76 ff ff ff jmp simple_strtoull
ffffffff81da024a: 48 83 c7 01 add rdi,0x1
ffffffff81da024e: e8 6d ff ff ff call simple_strtoull
ffffffff81da0253: 48 f7 d8 neg rax
ffffffff81da0256: c3 ret
Space savings (on F34-ish .config)
add/remove: 0/0 grow/shrink: 1/3 up/down: 52/-313 (-261)
Function old new delta
vsscanf 2167 2219 +52
simple_strtoul 72 2 -70
simple_strtoll 143 23 -120
simple_strtol 143 20 -123
Link: https://lkml.kernel.org/r/YMO2zoOQk2eF34tn@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/vsprintf.c')
| -rw-r--r-- | lib/vsprintf.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index cc281f5895f9..30e1bc22105c 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -61,6 +61,7 @@ * * This function has caveats. Please use kstrtoull instead. */ +noinline unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) { unsigned long long result; |