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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
        Andrey Vagin <avagin@openvz.org>
Cc:     Frederic Weisbecker <frederic@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Anna-Maria Behnsen <anna-maria@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
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        Dmitry Vyukov <dvyukov@google.com>,
        Sebastian Siewior <bigeasy@linutronix.de>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Christian Brauner <brauner@kernel.org>,
        Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>,
        Pavel Emelyanov <xemul@openvz.org>
Subject: Re: [RFD] posix-timers: CRIU woes
In-Reply-To: <cc8aa6a4-a187-f3ad-fec9-05f037a3886d@virtuozzo.com>
References: <20230425181827.219128101@linutronix.de>
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Date:   Thu, 11 May 2023 11:36:31 +0200
Message-ID: <87r0rnciqo.ffs@tglx>
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On Thu, May 11 2023 at 11:17, Pavel Tikhomirov wrote:
> On 10.05.2023 16:16, Andrey Vagin wrote:
>>>
>>> So because of that half thought out user space ABI we are now up the
>>> regression creek without a paddle, unless CRIU can accomodate to a
>>> different restore mechanism to lift this restriction from the kernel.
>>>
>> If you give us a new API to create timers with specified id-s, we will
>> figure out how to live with it. It isn't good to ask users to update
>> CRIU to work on new kernels, but here are reasons and event improvements
>> for CRIU, so I think it's worth it.
>
> I agree, any API to create timers with specified id-s would work for new 
> CRIU versions.

The real question is whether this will cause any upheaval when a new
kernel meets a non-updated CRIU stack.

You know the UABI regression rules of the kernel...

Thanks,

        tglx