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From: Florian Weimer <fweimer@redhat.com>
To: Alistair Francis <alistair.francis@wdc.com>
Cc: libc-alpha@sourceware.org,  arnd@arndb.de,
	 adhemerval.zanella@linaro.org,  palmer@sifive.com,
	 macro@wdc.com,  zongbox@gmail.com,  alistair23@gmail.com
Subject: Re: [RFC v3 05/23] sysdeps/timespec_get: Use clock_gettime64 if avaliable
Date: Wed, 17 Jul 2019 05:08:00 -0000	[thread overview]
Message-ID: <87zhlddz8v.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <0d116a8faab58db1952a256c6cb75e7b0f9af444.1563321715.git.alistair.francis@wdc.com> (Alistair Francis's message of "Tue, 16 Jul 2019 17:08:54 -0700")

* Alistair Francis:

> +#if __WORDSIZE == 32
> +int
> +__timespec_get (struct timespec *ts, int base)
> +{
> +   int ret;
> +
> +#ifdef __NR_clock_gettime64
> +  struct __timespec64 ts64;
> +  ret = INTERNAL_VSYSCALL (clock_gettime64, err, 2, CLOCK_REALTIME, &ts64);
> +
> +  ts->tv_sec = ts64.tv_sec;
> +  ts->tv_nsec = ts64.tv_nsec;
> +
> +  if (! in_time_t_range (ts->tv_sec))
> +    {
> +      __set_errno (EOVERFLOW);
> +      return -1;
> +    }
> +#endif
> +
> +#ifndef __ASSUME_TIME64_SYSCALLS
> +  ret = INTERNAL_VSYSCALL (clock_gettime, err, 2, CLOCK_REALTIME, ts);
> +#endif

I don't think this is right.  I think you need to cache clock_gettime64
support somewhere and avoid trying to call the non-existing system call
again and again.  And the second system call will overwrite the results
of the first.

Thanks,
Florian

  reply	other threads:[~2019-07-17  5:08 UTC|newest]

Thread overview: 127+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-17  0:11 [RFC v3 00/23] RISC-V glibc port for the 32-bit Alistair Francis
2019-07-17  0:11 ` [RFC v3 08/23] RISC-V: define __NR_futex as __NR_futex_time64 for 32-bit Alistair Francis
2019-07-17  0:11 ` [RFC v3 01/23] sysdeps/nanosleep: Use clock_nanosleep_time64 if avaliable Alistair Francis
2019-07-17  5:16   ` Florian Weimer
2019-07-19 17:29     ` Alistair Francis
2019-07-20 14:24       ` Stepan Golosunov
2019-07-22 21:17         ` Alistair Francis
2019-07-17  0:11 ` [RFC v3 03/23] sysdeps/wait: Use waitid " Alistair Francis
2019-07-17  5:31   ` Florian Weimer
2019-07-19 17:52     ` Alistair Francis
2019-07-22 15:58       ` Florian Weimer
2019-07-22 21:06         ` Alistair Francis
2019-07-21  4:03   ` Rich Felker
2019-07-21  4:20     ` Rich Felker
2019-07-21 11:59       ` Eric W. Biederman
2019-07-21 23:00         ` Rich Felker
2019-07-21  7:57     ` Arnd Bergmann
2019-07-21 12:15       ` Eric W. Biederman
2019-07-21 12:28         ` Christian Brauner
2019-07-21 14:31         ` Arnd Bergmann
2019-07-21 15:45           ` Eric W. Biederman
2019-07-21 17:06             ` Arnd Bergmann
2019-07-21 17:22             ` Linus Torvalds
2019-07-21 21:40               ` Eric W. Biederman
2019-07-21 23:24                 ` Rich Felker
2019-07-23  0:01                   ` Eric W. Biederman
2019-07-23  8:12                     ` Arnd Bergmann
2019-07-23  8:29                       ` Christian Brauner
2019-07-23  8:45                         ` Arnd Bergmann
2019-07-25  0:08                           ` Alistair Francis
2019-07-25  4:40                             ` Rich Felker
2019-07-25 13:23                               ` Arnd Bergmann
2019-07-25 16:06                                 ` Christian Brauner
2019-07-25 17:14                                 ` Eric W. Biederman
2019-07-25 17:30                                   ` Christian Brauner
2019-08-13 22:25                                     ` Alistair Francis
2019-08-13 23:12                                       ` Rich Felker
2019-08-14  5:07                                         ` Christian Brauner
2019-08-14 11:40                                       ` [PATCH v1 0/1] waitid: process group enhancement christian.brauner
2019-08-14 11:40                                         ` [PATCH v1 1/1] waitid: Add support for waiting for the current process group christian.brauner
2019-08-14 12:29                                           ` Oleg Nesterov
2019-08-14 12:46                                             ` Christian Brauner
2019-08-14 12:50                                               ` Oleg Nesterov
2019-08-14 12:53                                                 ` Christian Brauner
2019-08-14 13:10                                       ` [PATCH v2 0/1] waitid: process group enhancement Christian Brauner
2019-08-14 13:10                                         ` [PATCH v2 1/1] waitid: Add support for waiting for the current process group Christian Brauner
2019-08-14 14:20                                           ` Oleg Nesterov
2019-08-14 14:35                                             ` Christian Brauner
2019-08-14 15:27                                               ` Oleg Nesterov
2019-08-14 15:30                                                 ` Christian Brauner
2019-08-14 15:46                                       ` [PATCH v3 0/1] waitid: process group enhancement Christian Brauner
2019-08-14 15:46                                         ` [PATCH v3 1/1] waitid: Add support for waiting for the current process group Christian Brauner
2019-08-14 16:09                                           ` Oleg Nesterov
2019-08-14 16:15                                             ` Christian Brauner
2019-08-14 16:34                                               ` Christian Brauner
2019-08-14 16:55                                                 ` Rich Felker
2019-08-14 17:02                                                   ` Christian Brauner
2019-08-14 17:06                                                   ` Linus Torvalds
2019-08-14 18:00                                                     ` Rich Felker
2019-08-14 20:50                                             ` Christian Brauner
2019-08-14 15:58                                         ` [PATCH v3 0/1] waitid: process group enhancement Rich Felker
2019-08-14 16:13                                           ` Christian Brauner
2019-07-26 23:39                                   ` [RFC v3 03/23] sysdeps/wait: Use waitid if avaliable Alistair Francis
2019-07-17  0:11 ` [RFC v3 04/23] sysdeps/clock_gettime: Use clock_gettime64 " Alistair Francis
2019-07-17  5:39   ` Florian Weimer
2019-07-17  8:04     ` Arnd Bergmann
2019-07-17  8:44       ` Florian Weimer
2019-07-17  9:10         ` Arnd Bergmann
2019-07-17 15:16           ` Florian Weimer
2019-07-18  7:39             ` Arnd Bergmann
2019-07-18  8:19               ` Florian Weimer
2019-07-18  9:15                 ` Arnd Bergmann
2019-07-18 18:10                 ` Adhemerval Zanella
2019-07-19 21:06     ` Alistair Francis
2019-07-17  7:03   ` Andreas Schwab
2019-07-17 12:37   ` Lukasz Majewski
2019-07-17  0:11 ` [RFC v3 02/23] sysdeps/gettimeofday: " Alistair Francis
2019-07-17  7:09   ` Florian Weimer
2019-07-20  3:21     ` Rich Felker
2019-07-25 20:54       ` Joseph Myers
2019-07-17 12:43   ` Lukasz Majewski
2019-07-17 12:48     ` Lukasz Majewski
2019-07-19 22:29     ` Alistair Francis
2019-07-17  0:12 ` [RFC v3 13/23] RISC-V: Use 64-bit timespec in clock_gettime vdso calls Alistair Francis
2019-07-17  8:14   ` Arnd Bergmann
2019-07-17  0:12 ` [RFC v3 09/23] RISC-V: define __NR_* as __NR_*_time64/64 for 32-bit Alistair Francis
2019-07-17  0:12 ` [RFC v3 23/23] RISC-V: Use 64-bit vdso syscalls Alistair Francis
2019-07-17  5:33   ` Florian Weimer
2019-07-17  8:02     ` Arnd Bergmann
2019-07-17 22:27       ` Alistair Francis
2019-07-17 23:46         ` Alistair Francis
2019-07-18  0:05           ` Alistair Francis
2019-07-17  0:12 ` [RFC v3 17/23] RISC-V: Hard float support for the 32 bit Alistair Francis
2019-07-17  0:12 ` [RFC v3 20/23] RISC-V: Build Infastructure for the 32-bit Alistair Francis
2019-07-17  0:12 ` [RFC v3 19/23] RISC-V: Add ABI lists Alistair Francis
2019-07-17  0:12 ` [RFC v3 14/23] RISC-V: Support dynamic loader for the 32-bit Alistair Francis
2019-07-17  0:12 ` [RFC v3 18/23] RISC-V: Regenerate ULPs of RISC-V Alistair Francis
2019-07-17  0:12 ` [RFC v3 05/23] sysdeps/timespec_get: Use clock_gettime64 if avaliable Alistair Francis
2019-07-17  5:08   ` Florian Weimer [this message]
2019-07-17  7:59     ` Arnd Bergmann
2019-07-17  8:12       ` Florian Weimer
2019-07-17  8:23         ` Arnd Bergmann
2019-07-17  8:41           ` Florian Weimer
2019-07-17  8:54             ` Arnd Bergmann
2019-07-25 20:14       ` Joseph Myers
2019-07-17 12:23   ` Lukasz Majewski
2019-07-17  0:12 ` [RFC v3 21/23] RISC-V: Fix llrint and llround missing exceptions on RV32 Alistair Francis
2019-07-17 12:22   ` Florian Weimer
2019-07-17 22:35     ` Alistair Francis
2019-07-17  0:12 ` [RFC v3 06/23] Documentation for the RISC-V 32-bit port Alistair Francis
2019-07-17  0:12 ` [RFC v3 07/23] RISC-V: Use 64-bit time_t and off_t for RV32 and RV64 Alistair Francis
2019-07-17  8:27   ` Arnd Bergmann
2019-07-17 22:43     ` Alistair Francis
2019-07-18  7:41       ` Arnd Bergmann
2019-07-18 17:36         ` Alistair Francis
2019-07-19  6:44           ` Arnd Bergmann
2019-07-19 17:06             ` Alistair Francis
2019-07-17  0:12 ` [RFC v3 22/23] Add RISC-V 32-bit target to build-many-glibcs.py Alistair Francis
2019-07-17  0:12 ` [RFC v3 12/23] RISC-V: define __vdso_clock_gettime as __vdso_clock_gettime64 for 32-bit Alistair Francis
2019-07-17  8:16   ` Arnd Bergmann
2019-07-19 17:19     ` Alistair Francis
2019-07-17  0:12 ` [RFC v3 16/23] RISC-V: The ABI implementation for the 32-bit Alistair Francis
2019-07-17  0:12 ` [RFC v3 10/23] RISC-V: define __NR_clock_getres as __NR_*_time64 for 32-bit Alistair Francis
2019-07-17  0:12 ` [RFC v3 15/23] RISC-V: Add path of library directories for the 32-bit Alistair Francis
2019-07-17 12:20   ` Florian Weimer
2019-07-17  0:12 ` [RFC v3 11/23] RISC-V: define __vdso_clock_getres as __vdso_clock_getres_time64 for 32-bit Alistair Francis
2019-07-19 17:18 ` [RFC v3 00/23] RISC-V glibc port for the 32-bit Alistair Francis

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