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Date: Fri, 27 Jun 2014 17:07:52 -0600
From: David Ahern <dsahern@gmail.com>
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To: Jiri Olsa <jolsa@kernel.org>, linux-kernel@vger.kernel.org
CC: Arnaldo Carvalho de Melo <acme@kernel.org>,
        Corey Ashford <cjashfor@linux.vnet.ibm.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, Jean Pihet <jean.pihet@linaro.org>,
        Namhyung Kim <namhyung@kernel.org>, Paul Mackerras <paulus@samba.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 08/18] perf tools: Flush ordered events in case of allocation
 failure
References: <1403103539-16807-1-git-send-email-jolsa@kernel.org> <1403103539-16807-9-git-send-email-jolsa@kernel.org>
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On 6/18/14, 8:58 AM, Jiri Olsa wrote:
> +	case OEQ_FLUSH__HALF:
> +	{
> +		struct ordered_event *first, *last;
> +		struct list_head *head = &q->events;
> +
> +		first = list_entry(head->next, struct ordered_event, list);
> +		last = q->last;
> +
> +		if (WARN_ONCE(!last || list_empty(head), "empty queue"))
> +			return 0;

Maybe a comment that the WARN_ONCE can only happen if perf can't 
allocate an ordered event the first time through?

> +
> +		q->next_flush  = first->timestamp;
> +		q->next_flush += (last->timestamp - first->timestamp) / 2;
> +		break;
> +	}
> +


David