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Date: Tue, 19 Jan 2016 21:07:22 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org,
        vince@deater.net, eranian@google.com,
        Arnaldo Carvalho de Melo <acme@infradead.org>,
        Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH v2] perf: Synchronously cleanup child events
Message-ID: <20160119200722.GD6357@twins.programming.kicks-ass.net>
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On Tue, Jan 19, 2016 at 05:12:34PM +0200, Alexander Shishkin wrote:
> +static bool put_event_last(struct perf_event *event)
>  {
> +	if (atomic_long_cmpxchg(&event->refcount, 1, 0)) {

	if (atomic_long_cmpxchg(&event->refcount, 1, 0) == 1) {

> +		__put_event(event);
> +		return true;
> +	}
> +
> +	return false;
>  }