From ad65dcef3a87c24d6c6156eae5e7b47311d6e3cf Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Wed, 30 Jun 2021 18:56:04 -0700 Subject: 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 : ffffffff81da0240: 80 3f 2d cmp BYTE PTR [rdi],0x2d ffffffff81da0243: 74 05 je ffffffff81da024a 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/vsprintf.c | 1 + 1 file changed, 1 insertion(+) 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; -- cgit v1.2.3-59-g8ed1b