From: Andrey Vagin <avagin@openvz.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
syzbot+5c54bd3eb218bb595aa9@syzkaller.appspotmail.com,
Dmitry Vyukov <dvyukov@google.com>,
Sebastian Siewior <bigeasy@linutronix.de>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: [patch 02/20] posix-timers: Ensure timer ID search-loop limit is valid
Date: Tue, 9 May 2023 17:42:43 -0700 [thread overview]
Message-ID: <CANaxB-zyaS2OZsdmAGRjz8ZQxGUU8b_cEAgtXNmUW+hyCLY9GQ@mail.gmail.com> (raw)
In-Reply-To: <875y911xeg.ffs@tglx>
On Tue, May 9, 2023 at 5:50 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Tue, May 09 2023 at 11:30, Thomas Gleixner wrote:
> > On Mon, May 08 2023 at 23:57, Thomas Gleixner wrote:
> >> More thoughts on this. If we go there and accept the extra page of
> >> memory then we can just go all the way and make the xarray per process,
> >> actually per signal.
> >
> > Thinking more about it. The current scheme how timer ID allocation works
> > is really interesting vs. CRIU.
> >
> > Assume a process creates/deletes timers frequently. It's not hard to
> > move the next ID close to INT_MAX, i.e. 2G
> >
> > Now checkpoint that thing and restore it which means to do the
> > create/delete dance to move next ID up to the last one-1. Will only take
> > a couple of hours....
>
> I'm cursing myself for overlooking this back then when the CRIU changes
> to the timer ID management were made. Why?
>
> Because that created an ABI which CRIU relies on.
>
> The proper solution for this would be to make it possible to create a
> timer with a given ID. That's not rocket science, but we need buy in
> from the CRIU folks. Otherwise we are up the regression creek without a
> paddle.
Let's go with the proper solution. I will prepare CRIU changes when
kernel patches are ready.
Thanks,
Andrei
next prev parent reply other threads:[~2023-05-10 0:43 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-25 18:48 [patch 00/20] posix-timers: Fixes and cleanups Thomas Gleixner
2023-04-25 18:48 ` [patch 01/20] posix-timers: Prevent RT livelock in itimer_delete() Thomas Gleixner
2023-05-04 17:06 ` Frederic Weisbecker
2023-05-04 18:20 ` Thomas Gleixner
2023-05-05 7:57 ` Thomas Gleixner
2023-06-01 19:00 ` [patch v2 " Thomas Gleixner
2023-06-01 20:16 ` [patch v2a " Thomas Gleixner
2023-06-05 10:59 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:48 ` [patch 02/20] posix-timers: Ensure timer ID search-loop limit is valid Thomas Gleixner
2023-05-05 14:50 ` Frederic Weisbecker
2023-05-05 22:58 ` Thomas Gleixner
2023-05-05 23:36 ` Thomas Gleixner
2023-05-08 21:57 ` Thomas Gleixner
2023-05-09 9:30 ` Thomas Gleixner
2023-05-09 12:50 ` Thomas Gleixner
2023-05-09 21:42 ` [RFD] posix-timers: CRIU woes Thomas Gleixner
2023-05-10 4:36 ` Pavel Tikhomirov
2023-05-10 8:30 ` Thomas Gleixner
2023-05-11 4:12 ` Pavel Tikhomirov
2023-05-11 7:56 ` Peter Zijlstra
2023-05-11 9:32 ` Thomas Gleixner
2023-05-11 10:13 ` David Laight
2023-05-10 8:16 ` Andrey Vagin
2023-05-11 3:17 ` Pavel Tikhomirov
2023-05-11 9:36 ` Thomas Gleixner
2023-05-11 9:52 ` Pavel Tikhomirov
2023-05-11 13:42 ` Thomas Gleixner
2023-05-11 14:54 ` Pavel Tikhomirov
2023-05-11 15:25 ` Pavel Tikhomirov
2023-05-12 1:21 ` Andrey Vagin
2023-05-31 17:38 ` Thomas Gleixner
2023-05-11 7:49 ` Cyrill Gorcunov
2023-05-10 0:42 ` Andrey Vagin [this message]
2023-05-09 9:42 ` [patch 02/20] posix-timers: Ensure timer ID search-loop limit is valid Frederic Weisbecker
2023-05-09 12:04 ` Thomas Gleixner
2023-05-09 12:38 ` Thomas Gleixner
2023-05-09 14:18 ` Frederic Weisbecker
2023-06-01 18:58 ` [patch v2 " Thomas Gleixner
2023-06-05 14:17 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 03/20] posix-timers: Clarify timer_wait_running() comment Thomas Gleixner
2023-05-09 9:50 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 04/20] posix-timers: Cleanup comments about timer ID tracking Thomas Gleixner
2023-05-09 9:58 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 05/20] posix-timers: Add comments about timer lookup Thomas Gleixner
2023-05-09 10:58 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 06/20] posix-timers: Annotate concurrent access to k_itimer::it_signal Thomas Gleixner
2023-05-09 11:04 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] posix-timers: Annotate concurrent access to k_itimer:: It_signal tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 07/20] posix-timers: Set k_itimer::it_signal to NULL on exit() Thomas Gleixner
2023-06-01 10:09 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] posix-timers: Set k_itimer:: It_signal " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 08/20] posix-timers: Remove pointless irqsafe from hash_lock Thomas Gleixner
2023-06-01 10:12 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 09/20] posix-timers: Split release_posix_timers() Thomas Gleixner
2023-06-01 10:25 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 10/20] posix-timers: Document sys_clock_getres() correctly Thomas Gleixner
2023-06-01 10:44 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 11/20] posix-timers: Document common_clock_get() correctly Thomas Gleixner
2023-06-01 11:00 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 12/20] posix-timers: Document sys_clock_getoverrun() Thomas Gleixner
2023-06-01 11:06 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 13/20] posix-timers: Document sys_clock_settime() permissions in place Thomas Gleixner
2023-06-01 11:22 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:50 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 14/20] posix-timers: Document nanosleep() details Thomas Gleixner
2023-06-01 12:30 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 15/20] posix-timers: Add proper comments in do_timer_create() Thomas Gleixner
2023-06-01 12:43 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 16/20] posix-timers: Comment SIGEV_THREAD_ID properly Thomas Gleixner
2023-06-01 12:47 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 17/20] posix-timers: Clarify posix_timer_rearm() comment Thomas Gleixner
2023-06-01 12:52 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 18/20] posix-timers: Clarify posix_timer_fn() comments Thomas Gleixner
2023-06-01 13:21 ` Frederic Weisbecker
2023-06-01 18:43 ` Thomas Gleixner
2023-06-01 19:07 ` Thomas Gleixner
2023-06-05 14:26 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-05 22:17 ` tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 19/20] posix-timers: Remove pointless comments Thomas Gleixner
2023-06-01 13:48 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-05 22:17 ` tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-04-25 18:49 ` [patch 20/20] posix-timers: Polish coding style in a few places Thomas Gleixner
2023-06-01 13:50 ` Frederic Weisbecker
2023-06-05 15:08 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2023-06-05 22:17 ` tip-bot2 for Thomas Gleixner
2023-06-18 20:49 ` tip-bot2 for Thomas Gleixner
2023-06-05 14:32 ` [patch 00/20] posix-timers: Fixes and cleanups Frederic Weisbecker
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