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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/getrlimit64.c
parent2028f49dabb94bd56a85a7be16141bee4853aae6 (diff)
downloadglibc-hjl/i386/master.tar.gz
glibc-hjl/i386/master.tar.xz
glibc-hjl/i386/master.zip
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/getrlimit64.c')
-rw-r--r--sysdeps/unix/sysv/linux/getrlimit64.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/sysdeps/unix/sysv/linux/getrlimit64.c b/sysdeps/unix/sysv/linux/getrlimit64.c
index 100ba623e2..bc36c1466f 100644
--- a/sysdeps/unix/sysv/linux/getrlimit64.c
+++ b/sysdeps/unix/sysv/linux/getrlimit64.c
@@ -30,9 +30,13 @@ __getrlimit64 (enum __rlimit_resource resource, struct rlimit64 *rlimits)
   return INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits);
 #else
 # ifdef __NR_prlimit64
-  int res = INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits);
-  if (res == 0 || errno != ENOSYS)
+  INTERNAL_SYSCALL_DECL (err);
+  int res = INTERNAL_SYSCALL (prlimit64, err, 4, 0, resource, NULL,
+			      rlimits);
+  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));
 # endif
   struct rlimit rlimits32;