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From: Thomas Gleixner <tglx@linutronix.de>
To: Eric Dumazet <edumazet@google.com>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>,
	Frederic Weisbecker <frederic@kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Benjamin Segall <bsegall@google.com>,
	Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH V2 1/4] posix-timers: Make next_posix_timer_id an atomic_t
Date: Thu, 20 Feb 2025 17:19:11 +0100	[thread overview]
Message-ID: <87wmdkh9mo.ffs@tglx> (raw)
In-Reply-To: <CANn89iKAiJvOXLC4SkWnsKC-6m9HU1KoYAVPE_G_UhOb__Gj0g@mail.gmail.com>

On Thu, Feb 20 2025 at 16:55, Eric Dumazet wrote:
> On Thu, Feb 20, 2025 at 3:32 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>>
>> On Thu, Feb 20 2025 at 15:04, Thomas Gleixner wrote:
>> > On Thu, Feb 20 2025 at 09:49, Eric Dumazet wrote:
>> >> On Thu, Feb 20, 2025 at 9:09 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>> >>> > This allows the following patch to use RCU.
>> >>>
>> >>> Your patch ordering is slightly off by two :)
>> >>>
>> >>> And it fails to explain for what RCU can be used....
>> >>
>> >> This is explained in the following patches.
>> >
>> > The changelog of a patch has to be self contained. The 'following patch'
>> > has no meaning when the patch is merged.
>>
>> That said, please just fold this into the patch which actually does this RCU
>> lookup upfront. The change is trivial enough that it does not really
>> require to be seperate. If the lockless increment would cause issues,
>> then the subsequent RCU lookup is the least of the worries :)
>
> I can squash all patches into a single one if you prefer.

Please don't. The wraparound race prevention has nothing to do with the
lookup optimization.

Thanks,

        tglx

  reply	other threads:[~2025-02-20 16:19 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-19 12:55 [PATCH V2 0/4] posix-timers: Reduce spinlock contention Eric Dumazet
2025-02-19 12:55 ` [PATCH V2 1/4] posix-timers: Make next_posix_timer_id an atomic_t Eric Dumazet
2025-02-20  8:09   ` Thomas Gleixner
2025-02-20  8:49     ` Eric Dumazet
2025-02-20 14:04       ` Thomas Gleixner
2025-02-20 14:32         ` Thomas Gleixner
2025-02-20 15:55           ` Eric Dumazet
2025-02-20 16:19             ` Thomas Gleixner [this message]
2025-02-19 12:55 ` [PATCH V2 2/4] posix-timers: Initialise timer->it_id in posix_timer_add() Eric Dumazet
2025-02-20  8:12   ` Thomas Gleixner
2025-02-20  8:48     ` Eric Dumazet
2025-02-20 14:10       ` Thomas Gleixner
2025-02-19 12:55 ` [PATCH V2 3/4] posix-timers: Initialise timer->it_signal " Eric Dumazet
2025-02-20  8:19   ` Thomas Gleixner
2025-02-20  8:44     ` Eric Dumazet
2025-02-20 14:13       ` Thomas Gleixner
2025-02-19 12:55 ` [PATCH V2 4/4] posix-timers: Use RCU " Eric Dumazet
2025-02-19 19:38   ` David Laight
2025-02-19 19:46     ` Eric Dumazet
2025-02-24  9:33   ` Thomas Gleixner
2025-02-24  9:58     ` Eric Dumazet

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