From: Laurent Vivier <lvivier@redhat.com>
To: Dmitry Safonov <dima@arista.com>, linux-kernel@vger.kernel.org
Cc: Dmitry Safonov <0x7f454c46@gmail.com>,
Andrei Vagin <avagin@openvz.org>, Adrian Reber <adrian@lisas.de>,
Andy Lutomirski <luto@kernel.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Jeff Dike <jdike@addtoit.com>, Oleg Nesterov <oleg@redhat.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Shuah Khan <shuah@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
containers@lists.linux-foundation.org, criu@openvz.org,
linux-api@vger.kernel.org, x86@kernel.org
Subject: Re: [RFC 01/20] ns: Introduce Time Namespace
Date: Fri, 28 Sep 2018 20:20:10 +0200 [thread overview]
Message-ID: <2087cf9b-89a1-e591-4dcd-4d98767a1be6@redhat.com> (raw)
In-Reply-To: <20180919205037.9574-2-dima@arista.com>
On 19/09/2018 22:50, Dmitry Safonov wrote:
> From: Andrei Vagin <avagin@openvz.org>
>
> Time Namespace isolates clock values.
>
> The kernel provides access to several clocks CLOCK_REALTIME,
> CLOCK_MONOTONIC, CLOCK_BOOTTIME, etc.
>
> CLOCK_REALTIME
> System-wide clock that measures real (i.e., wall-clock) time.
>
> CLOCK_MONOTONIC
> Clock that cannot be set and represents monotonic time since
> some unspecified starting point.
>
> CLOCK_BOOTTIME
> Identical to CLOCK_MONOTONIC, except it also includes any time
> that the system is suspended.
>
> For many users, the time namespace means the ability to changes time in
> a container (CLOCK_REALTIME).
>
> But in a context of the checkpoint/restore functionality, monotonic and
> bootime clocks become interesting. Both clocks are monotonic with
> unspecified staring points. These clocks are widely used to measure time
> slices, set timers. After restoring or migrating processes, we have to
> guarantee that they never go backward. In an ideal case, the behavior of
> these clocks should be the same as for a case when a whole system is
> suspended. All this means that we need to be able to set CLOCK_MONOTONIC
> and CLOCK_BOOTTIME clocks, what can be done by adding per-namespace
> offsets for clocks.
>
> Link: https://criu.org/Time_namespace
> Link: https://lists.openvz.org/pipermail/criu/2018-June/041504.html
> Signed-off-by: Andrei Vagin <avagin@openvz.org>
> Co-developed-by: Dmitry Safonov <dima@arista.com>
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---
> fs/proc/namespaces.c | 3 +
> include/linux/nsproxy.h | 1 +
> include/linux/proc_ns.h | 1 +
> include/linux/time_namespace.h | 59 ++++++++++++++
> include/linux/user_namespace.h | 1 +
> include/uapi/linux/sched.h | 1 +
> init/Kconfig | 7 ++
> kernel/Makefile | 1 +
> kernel/fork.c | 3 +-
> kernel/nsproxy.c | 19 ++++-
> kernel/time_namespace.c | 169 +++++++++++++++++++++++++++++++++++++++++
> 11 files changed, 262 insertions(+), 3 deletions(-)
> create mode 100644 include/linux/time_namespace.h
> create mode 100644 kernel/time_namespace.c
>
...
> diff --git a/kernel/time_namespace.c b/kernel/time_namespace.c
> new file mode 100644
> index 000000000000..902cd9c22159
> --- /dev/null
> +++ b/kernel/time_namespace.c
...
> +
> +struct time_namespace init_time_ns = {
> + .kref = KREF_INIT(2),
> + .user_ns = &init_user_ns,
> + .ns.inum = PROC_UTS_INIT_INO,
Do you mean PROC_TIME_INIT_INO?
> +#ifdef CONFIG_UTS_NS
> + .ns.ops = &timens_operations,
> +#endif
Do you mean CONFIG_TIME_NS?
Thanks,
Laurent
next prev parent reply other threads:[~2018-09-28 18:20 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 20:50 [RFC 00/20] ns: Introduce Time Namespace Dmitry Safonov
2018-09-19 20:50 ` [RFC 01/20] " Dmitry Safonov
2018-09-28 18:20 ` Laurent Vivier [this message]
2018-09-19 20:50 ` [RFC 02/20] timens: Add timens_offsets Dmitry Safonov
2018-09-20 18:45 ` Cyrill Gorcunov
2018-09-20 22:14 ` Cyrill Gorcunov
2018-09-19 20:50 ` [RFC 03/20] timens: Introduce CLOCK_MONOTONIC offsets Dmitry Safonov
2018-09-19 20:50 ` [RFC 04/20] timens: Introduce CLOCK_BOOTTIME offset Dmitry Safonov
2018-09-30 3:18 ` [LKP] [timens] 3cc8de9dcb: RIP:posix_get_boottime kernel test robot
2018-09-19 20:50 ` [RFC 05/20] timerfd/timens: Take into account ns clock offsets Dmitry Safonov
2018-09-19 20:50 ` [RFC 06/20] kernel: Take into account timens clock offsets in clock_nanosleep Dmitry Safonov
2018-09-19 20:50 ` [RFC 07/20] timens: Shift /proc/uptime Dmitry Safonov
2018-09-19 20:50 ` [RFC 08/20] x86/vdso: Restrict splitting vvar vma Dmitry Safonov
2018-09-19 20:50 ` [RFC 09/20] x86/vdso/timens: Add offsets page in vvar Dmitry Safonov
2018-09-19 20:50 ` [RFC 10/20] x86/vdso: Use set_normalized_timespec() to avoid 32 bit overflow Dmitry Safonov
2018-09-19 20:50 ` [RFC 11/20] x86/vdso: Purge timens page on setns()/unshare()/clone() Dmitry Safonov
2018-09-19 20:50 ` [RFC 12/20] x86/vdso: Look for vvar vma to purge timens page Dmitry Safonov
2018-09-19 20:50 ` [RFC 13/20] posix-timers/timens: Take into account clock offsets Dmitry Safonov
2018-09-30 3:11 ` [LKP] [posix] 25217c6e39: BUG:KASAN:null-ptr-deref_in_c kernel test robot
2018-09-19 20:50 ` [RFC 14/20] timens: Add align for timens_offsets Dmitry Safonov
2018-09-19 20:50 ` [RFC 15/20] timens: Optimize zero-offsets Dmitry Safonov
2018-09-19 20:50 ` [RFC 16/20] selftest: Add Time Namespace test for supported clocks Dmitry Safonov
2018-09-24 21:36 ` Shuah Khan
2018-09-19 20:50 ` [RFC 17/20] selftest/timens: Add test for timerfd Dmitry Safonov
2018-09-19 20:50 ` [RFC 18/20] selftest/timens: Add test for clock_nanosleep Dmitry Safonov
2018-09-19 20:50 ` [RFC 19/20] timens/selftest: Add procfs selftest Dmitry Safonov
2018-09-19 20:50 ` [RFC 20/20] timens/selftest: Add timer offsets test Dmitry Safonov
2018-09-21 12:27 ` [RFC 00/20] ns: Introduce Time Namespace Eric W. Biederman
2018-09-24 20:51 ` Andrey Vagin
2018-09-24 22:02 ` Eric W. Biederman
2018-09-25 1:42 ` Andrey Vagin
2018-09-26 17:36 ` Eric W. Biederman
2018-09-26 17:59 ` Dmitry Safonov
2018-09-27 21:30 ` Thomas Gleixner
2018-09-27 21:41 ` Thomas Gleixner
2018-10-01 23:20 ` Andrey Vagin
2018-10-02 6:15 ` Thomas Gleixner
2018-10-02 21:05 ` Dmitry Safonov
2018-10-02 21:26 ` Thomas Gleixner
2018-09-28 17:03 ` Eric W. Biederman
2018-09-28 19:32 ` Thomas Gleixner
2018-10-01 9:05 ` Eric W. Biederman
2018-10-01 9:15 ` Setting monotonic time? Eric W. Biederman
2018-10-01 18:52 ` Thomas Gleixner
2018-10-02 20:00 ` Arnd Bergmann
2018-10-02 20:06 ` Thomas Gleixner
2018-10-03 4:50 ` Eric W. Biederman
2018-10-03 5:25 ` Thomas Gleixner
2018-10-03 6:14 ` Eric W. Biederman
2018-10-03 7:02 ` Arnd Bergmann
2018-10-03 6:14 ` Thomas Gleixner
2018-10-01 20:51 ` Andrey Vagin
2018-10-02 6:16 ` Thomas Gleixner
2018-10-21 1:41 ` [RFC 00/20] ns: Introduce Time Namespace Andrei Vagin
2018-10-21 3:54 ` Andrei Vagin
2018-10-29 20:33 ` Thomas Gleixner
2018-10-29 21:21 ` Eric W. Biederman
2018-10-29 21:36 ` Thomas Gleixner
2018-10-31 16:26 ` Andrei Vagin
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