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Date:   Fri, 29 May 2020 15:01:52 +0200
From:   Frederic Weisbecker <frederic@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     tglx@linutronix.de, linux-kernel@vger.kernel.org, x86@kernel.org,
        cai@lca.pw, mgorman@techsingularity.net
Subject: Re: [RFC][PATCH 4/7] smp: Optimize send_call_function_single_ipi()
Message-ID: <20200529130150.GA19915@lenoir>
References: <20200526161057.531933155@infradead.org>
 <20200526161907.953304789@infradead.org>
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On Tue, May 26, 2020 at 06:11:01PM +0200, Peter Zijlstra wrote:
> +void flush_smp_call_function_from_idle(void)
> +{
> +	unsigned long flags;
> +
> +	if (llist_empty(this_cpu_ptr(&call_single_queue)))
> +		return;

Now it seems weird that sched_ttwu_pending() didn't have that
llist_empty() optimization. The ordering should allow it.

Anyway,

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>