linux-kernel - Re: [PATCH v12 3/3]: perf record: extend trace writing to multi AIO

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Message-ID: <20181011134605.GD29634@krava>
Date:   Thu, 11 Oct 2018 15:46:05 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v12 3/3]: perf record: extend trace writing to multi AIO

On Tue, Oct 09, 2018 at 11:59:31AM +0300, Alexey Budankov wrote:

SNIP

> @@ -709,12 +729,13 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli
>  					goto out;
>  				}
>  			} else {
> +				int idx;
>  				/*
>  				 * Call record__aio_sync() to wait till map->data buffer
>  				 * becomes available after previous aio write request.
>  				 */
> -				record__aio_sync(map);
> -				if (perf_mmap__aio_push(map, rec, record__aio_pushfn, &off) != 0) {
> +				idx = record__aio_sync(map, false);

looks like record__aio_sync can return -1,
how is it not breaking the perf_mmap__aio_push call below?

> +				if (perf_mmap__aio_push(map, rec, idx, record__aio_pushfn, &off) != 0) {
>  					record__aio_set_pos(trace_fd, off);
>  					rc = -1;
>  					goto out;

SNIP