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authorH.J. Lu <hjl.tools@gmail.com>2015-08-21 14:46:05 -0700
committerH.J. Lu <hjl.tools@gmail.com>2015-10-19 10:45:25 -0700
commit6f6e3ee567cbff328df83dcf9ee0a5459746fce0 (patch)
treea61f9d12d5b24e37ac8d4e39c9585e37e0e4f900 /sysdeps/unix/sysv/linux/fstatfs64.c
parent2028f49dabb94bd56a85a7be16141bee4853aae6 (diff)
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Avoid reading errno in syscall implementations hjl/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/fstatfs64.c')
-rw-r--r--sysdeps/unix/sysv/linux/fstatfs64.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/sysdeps/unix/sysv/linux/fstatfs64.c b/sysdeps/unix/sysv/linux/fstatfs64.c
index af8383010f..819b6238a5 100644
--- a/sysdeps/unix/sysv/linux/fstatfs64.c
+++ b/sysdeps/unix/sysv/linux/fstatfs64.c
@@ -35,12 +35,17 @@ __fstatfs64 (int fd, struct statfs64 *buf)
   if (! __no_statfs64)
 # endif
     {
-      int result = INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf);
-
 # if __ASSUME_STATFS64 == 0
-      if (result == 0 || errno != ENOSYS)
-# endif
+      INTERNAL_SYSCALL_DECL (err);
+      int result = INTERNAL_SYSCALL (fstatfs64, err, 3, fd,
+				     sizeof (*buf), buf);
+      if (!__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
 	return result;
+      else if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
+	return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result, err));
+# else
+      return INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf);
+# endif
 
 # if __ASSUME_STATFS64 == 0
       __no_statfs64 = 1;