linux-kernel - Re: [PATCH 08/10] perf kvm stat live: Use perf_evlist__add

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Message-ID: <53FC9402.8080008@gmail.com>
Date:	Tue, 26 Aug 2014 08:04:50 -0600
From:	David Ahern <dsahern@...il.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Jiri Olsa <jolsa@...hat.com>
CC:	linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Jean Pihet <jean.pihet@...aro.org>,
	Jiri Olsa <jolsa@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH 08/10] perf kvm stat live: Use perf_evlist__add_pollfd()
 instead of local equivalent

On 8/22/14, 2:59 PM, Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <acme@...hat.com>
>
> Since we can add file descriptors to the evlist pollfd and it will
> autogrow, no need to copy all events to a local pollfd array, just add
> the timer and stdin file descriptors.
>
> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: Corey Ashford <cjashfor@...ux.vnet.ibm.com>
> Cc: David Ahern <dsahern@...il.com>
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Jean Pihet <jean.pihet@...aro.org>
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Link: http://lkml.kernel.org/n/tip-2hvp9iromiheh6rl4oaa08x5@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
>   tools/perf/builtin-kvm.c | 22 +++++++++-------------
>   1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
> index 1a4ef9cd9d5f..b192234096b6 100644
> --- a/tools/perf/builtin-kvm.c
> +++ b/tools/perf/builtin-kvm.c
> @@ -921,15 +921,8 @@ static int kvm_events_live_report(struct perf_kvm_stat *kvm)
>   	signal(SIGINT, sig_handler);
>   	signal(SIGTERM, sig_handler);
>
> -	/* copy pollfds -- need to add timerfd and stdin */
> +	/* use pollfds -- need to add timerfd and stdin */
>   	nr_fds = kvm->evlist->nr_fds;
> -	pollfds = zalloc(sizeof(struct pollfd) * (nr_fds + 2));
> -	if (!pollfds) {
> -		err = -ENOMEM;
> -		goto out;
> -	}
> -	memcpy(pollfds, kvm->evlist->pollfd,
> -		sizeof(struct pollfd) * kvm->evlist->nr_fds);
>
>   	/* add timer fd */
>   	if (perf_kvm__timerfd_create(kvm) < 0) {
> @@ -937,17 +930,21 @@ static int kvm_events_live_report(struct perf_kvm_stat *kvm)
>   		goto out;
>   	}
>
> -	pollfds[nr_fds].fd = kvm->timerfd;
> -	pollfds[nr_fds].events = POLLIN;
> +	if (perf_evlist__add_pollfd(kvm->evlist, kvm->timerfd))
> +		goto out;
> +
>   	nr_fds++;
>
> -	pollfds[nr_fds].fd = fileno(stdin);
> -	pollfds[nr_fds].events = POLLIN;
> +	if (perf_evlist__add_pollfd(kvm->evlist, fileno(stdin)))
> +		goto out;
> +
>   	nr_stdin = nr_fds;
>   	nr_fds++;
>   	if (fd_set_nonblock(fileno(stdin)) != 0)
>   		goto out;
>
> +	pollfds	 = kvm->evlist->pollfd;
> +
>   	/* everything is good - enable the events and process */
>   	perf_evlist__enable(kvm->evlist);
>
> @@ -981,7 +978,6 @@ out:
>   		close(kvm->timerfd);
>
>   	tcsetattr(0, TCSAFLUSH, &save);
> -	free(pollfds);
>   	return err;
>   }
>
>

Much simpler. Looks ok to me.

Reviewed-by: David Ahern <dsahern@...il.com>

David
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