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From:   Valentin Schneider <valentin.schneider@arm.com>
To:     Lai Jiangshan <jiangshanlai@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>, Qian Cai <cai@redhat.com>,
        Vincent Donnefort <vincent.donnefort@arm.com>,
        Dexuan Cui <decui@microsoft.com>,
        Lai Jiangshan <laijs@linux.alibaba.com>,
        Paul McKenney <paulmck@kernel.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH -tip V3 0/8] workqueue: break affinity initiatively
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References: <20201226025117.2770-1-jiangshanlai@gmail.com> <X/hGHNGB9fltElWB@hirez.programming.kicks-ass.net> <87o8hv7pnd.fsf@nanos.tec.linutronix.de> <X/wv7+PP8ywNYmIS@hirez.programming.kicks-ass.net> <X/yH9+MGa1JCNZ8x@hirez.programming.kicks-ass.net> <jhj7doj1dr1.mognet@arm.com> <X/yzrJw4UbQsK3KB@hirez.programming.kicks-ass.net> <CAJhGHyA0rfR92W7T7RnhPrmLMkmV4Mb7fUSeG2VEHhsH-pSxsw@mail.gmail.com>
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Date:   Tue, 12 Jan 2021 17:52:46 +0000
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On 12/01/21 12:33, Lai Jiangshan wrote:
>> I thought only pcpu pools would get the POOL_DISASSOCIATED flag on
>> offline, but it seems unbound pools also get it at init time. Did I get
>> that right?
>
> You are right.
>
> The POOL_DISASSOCIATED flag indicates whether the pool is concurrency
> management or not (negative way, POOL_DISASSOCIATED means "not concurrency
> management"). So it should be applied for all unbound pools.
>
> When !POOL_DISASSOCIATED means it is a percpu pool, and the pool->cpu
> is online and the offline callback has not been called yet even the pool->cpu
> is going to be offline.  So !POOL_DISASSOCIATED is used a lot in the code.

Thanks!