lib: uninline simple_strtoull()
authorAlexey Dobriyan <adobriyan@gmail.com>
Thu, 1 Jul 2021 01:56:04 +0000 (18:56 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 1 Jul 2021 18:06:05 +0000 (11:06 -0700)
commitad65dcef3a87c24d6c6156eae5e7b47311d6e3cf
treeae1fbd368809d911dfd43f38ecd9a38fabb62fe8
parent1a58be6277e4324c853babfd35890c2d5e171e8f
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>
lib/vsprintf.c