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Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer

From Jiri Olsa <jolsa@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer
Date 2016-07-06 13:40 +0200
Message-ID <rRTlo-bj-45@gated-at.bofh.it> (permalink)
References <rR5yh-2a2-3@gated-at.bofh.it> <rR5yh-2a2-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Mon, Jul 04, 2016 at 06:20:06AM +0000, Wang Nan wrote:

SNIP

> +static void
> +record__toggle_overwrite_evsels(struct record *rec,
> +				enum overwrite_evt_state state)
> +{
> +	struct perf_evlist *evlist = rec->overwrite_evlist;
> +	enum overwrite_evt_state old_state = rec->overwrite_evt_state;
> +	enum action {
> +		NONE,
> +		PAUSE,
> +		RESUME,
> +	} action = NONE;
> +
> +	switch (old_state) {
> +	case OVERWRITE_EVT_RUNNING: {
> +		switch (state) {
> +		case OVERWRITE_EVT_DATA_PENDING:
> +			action = PAUSE;
> +			break;
> +		case OVERWRITE_EVT_RUNNING:
> +		case OVERWRITE_EVT_EMPTY:
> +		default:
> +			goto state_err;
> +		}
> +		break;
> +	}
> +	case OVERWRITE_EVT_DATA_PENDING: {
> +		switch (state) {
> +		case OVERWRITE_EVT_EMPTY:
> +			break;
> +		case OVERWRITE_EVT_RUNNING:
> +		case OVERWRITE_EVT_DATA_PENDING:
> +		default:
> +			goto state_err;
> +		}
> +		break;
> +	}
> +	case OVERWRITE_EVT_EMPTY: {
> +		switch (state) {
> +		case OVERWRITE_EVT_RUNNING:
> +			action = RESUME;
> +			break;
> +		case OVERWRITE_EVT_EMPTY:
> +		case OVERWRITE_EVT_DATA_PENDING:
> +		default:
> +			goto state_err;
> +		}
> +		break;
> +	}
> +	default:
> +		WARN_ONCE(1, "Shouldn't get there\n");
> +	}
> +
> +	rec->overwrite_evt_state = state;
> +
> +	if (!evlist)
> +		return;

I'd expect this check at the begining

jirka

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Thread

[PATCH v13 5/8] perf record: Read from overwritable ring buffer Wang Nan <wangnan0@huawei.com> - 2016-07-04 08:30 +0200
  Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer Jiri Olsa <jolsa@redhat.com> - 2016-07-06 13:40 +0200
  Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer Jiri Olsa <jolsa@redhat.com> - 2016-07-06 13:40 +0200
    Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-07-06 14:10 +0200
      Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer Jiri Olsa <jolsa@redhat.com> - 2016-07-06 14:40 +0200
        Re: [PATCH v13 5/8] perf record: Read from overwritable ring buffer "Wangnan (F)" <wangnan0@huawei.com> - 2016-07-07 07:10 +0200

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