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| author | H.J. Lu <hjl.tools@gmail.com> | 2015-08-21 14:46:05 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2015-10-19 10:45:25 -0700 |
| commit | 6f6e3ee567cbff328df83dcf9ee0a5459746fce0 (patch) | |
| tree | a61f9d12d5b24e37ac8d4e39c9585e37e0e4f900 /sysdeps/unix/sysv/linux/eventfd.c | |
| parent | 2028f49dabb94bd56a85a7be16141bee4853aae6 (diff) | |
| download | glibc-hjl/i386/master.tar glibc-hjl/i386/master.tar.gz glibc-hjl/i386/master.tar.bz2 glibc-hjl/i386/master.zip | |
Avoid reading errno in syscall implementationshjl/i386/master
Reading errno is expensive for x86 PIC. With INTERNAL_SYSCALL,
INTERNAL_SYSCALL_ERROR_P, INTERNAL_SYSCALL_ERRNO and
INLINE_SYSCALL_ERROR_RETURN_VALUE, we can avoid reading errno.
There are no code changes on x86-64. On i686, libc.so sizes in bytes
show:
text data bss dec
after 1748495 11380 11132 1771007
before 1748403 11380 11132 1770915
* sysdeps/unix/sysv/linux/eventfd.c (eventfd): Use
INTERNAL_SYSCALL, INTERNAL_SYSCALL_ERROR_P and
INTERNAL_SYSCALL_ERRNO to avoid reading errno.
* sysdeps/unix/sysv/linux/fstatfs64.c (__fstatfs64): Likewise.
* sysdeps/unix/sysv/linux/getrlimit64.c (__getrlimit64):
Likewise.
* sysdeps/unix/sysv/linux/setrlimit64.c (setrlimit64):
Likewise.
* sysdeps/unix/sysv/linux/signalfd.c (signalfd): Likewise.
* sysdeps/unix/sysv/linux/statfs64.c (__statfs64): Likewise.
Diffstat (limited to 'sysdeps/unix/sysv/linux/eventfd.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/eventfd.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/sysdeps/unix/sysv/linux/eventfd.c b/sysdeps/unix/sysv/linux/eventfd.c index efce282617..3a9178183c 100644 --- a/sysdeps/unix/sysv/linux/eventfd.c +++ b/sysdeps/unix/sysv/linux/eventfd.c @@ -25,11 +25,16 @@ int eventfd (unsigned int count, int flags) { #ifdef __NR_eventfd2 - int res = INLINE_SYSCALL (eventfd2, 2, count, flags); # ifndef __ASSUME_EVENTFD2 - if (res != -1 || errno != ENOSYS) -# endif + INTERNAL_SYSCALL_DECL (err); + int res = INTERNAL_SYSCALL (eventfd2, err, 2, count, flags); + if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))) return res; + else if (INTERNAL_SYSCALL_ERRNO (res, err) != ENOSYS) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (res, err)); +# else + return INLINE_SYSCALL (eventfd2, 2, count, flags); +# endif #endif #ifndef __ASSUME_EVENTFD2 |