[07/18] linux: Remove supports_time64 () from clock_getres

Message ID 20210617115104.1359598-8-adhemerval.zanella@linaro.org
State New
Headers show
Series
  • More y2038 fixes
Related show

Commit Message

Paul A. Clarke via Libc-alpha June 17, 2021, 11:50 a.m.
It breaks the usage case of live migration like CRIU or similar.
The performance drawback is it would require an extra syscall
on older kernels without 64-bit time support.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.
---
 sysdeps/unix/sysv/linux/clock_getres.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

-- 
2.30.2

Comments

Lukasz Majewski June 21, 2021, 7:43 a.m. | #1
On Thu, 17 Jun 2021 08:50:53 -0300
Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote:

> It breaks the usage case of live migration like CRIU or similar.

> The performance drawback is it would require an extra syscall

> on older kernels without 64-bit time support.

> 

> Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel

> (with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

> ---

>  sysdeps/unix/sysv/linux/clock_getres.c | 16 +++++-----------

>  1 file changed, 5 insertions(+), 11 deletions(-)

> 

> diff --git a/sysdeps/unix/sysv/linux/clock_getres.c

> b/sysdeps/unix/sysv/linux/clock_getres.c index a9edec93e6..83f0593074

> 100644 --- a/sysdeps/unix/sysv/linux/clock_getres.c

> +++ b/sysdeps/unix/sysv/linux/clock_getres.c

> @@ -21,7 +21,6 @@

>  #include <time.h>

>  

>  #include <sysdep-vdso.h>

> -#include <time64-support.h>

>  #include <shlib-compat.h>

>  #include <kernel-features.h>

>  

> @@ -34,19 +33,14 @@ __clock_getres64 (clockid_t clock_id, struct

> __timespec64 *res) #ifndef __NR_clock_getres_time64

>  # define __NR_clock_getres_time64 __NR_clock_getres

>  #endif

> -  if (supports_time64 ())

> -    {

> +

>  #ifdef HAVE_CLOCK_GETRES64_VSYSCALL

> -      r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);

> +  r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);

>  #else

> -      r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);

> +  r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);

>  #endif

> -

> -      if (r == 0 || errno != ENOSYS)

> -	return r;

> -

> -      mark_time64_unsupported ();

> -    }

> +  if (r == 0 || errno != ENOSYS)

> +    return r;

>  

>  #ifndef __ASSUME_TIME64_SYSCALLS

>    /* Fallback code that uses 32-bit support.  */


Reviewed-by: Lukasz Majewski <lukma@denx.de>



Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Patch

diff --git a/sysdeps/unix/sysv/linux/clock_getres.c b/sysdeps/unix/sysv/linux/clock_getres.c
index a9edec93e6..83f0593074 100644
--- a/sysdeps/unix/sysv/linux/clock_getres.c
+++ b/sysdeps/unix/sysv/linux/clock_getres.c
@@ -21,7 +21,6 @@ 
 #include <time.h>
 
 #include <sysdep-vdso.h>
-#include <time64-support.h>
 #include <shlib-compat.h>
 #include <kernel-features.h>
 
@@ -34,19 +33,14 @@  __clock_getres64 (clockid_t clock_id, struct __timespec64 *res)
 #ifndef __NR_clock_getres_time64
 # define __NR_clock_getres_time64 __NR_clock_getres
 #endif
-  if (supports_time64 ())
-    {
+
 #ifdef HAVE_CLOCK_GETRES64_VSYSCALL
-      r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);
+  r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);
 #else
-      r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
+  r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
 #endif
-
-      if (r == 0 || errno != ENOSYS)
-	return r;
-
-      mark_time64_unsupported ();
-    }
+  if (r == 0 || errno != ENOSYS)
+    return r;
 
 #ifndef __ASSUME_TIME64_SYSCALLS
   /* Fallback code that uses 32-bit support.  */