linux-kernel - Re: [PATCH v7 8/8] perf record: Unmap overwrite evlist when event terminate

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Message-ID: <20160616205939.GB2471@redhat.com>
Date:	Thu, 16 Jun 2016 17:59:39 -0300
From:	Arnaldo Carvalho de Melo <acme@...hat.com>
To:	Wang Nan <wangnan0@...wei.com>
Cc:	acme@...nel.org, pi3orama@....com, linux-kernel@...r.kernel.org,
	He Kuang <hekuang@...wei.com>, Jiri Olsa <jolsa@...nel.org>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Zefan Li <lizefan@...wei.com>
Subject: Re: [PATCH v7 8/8] perf record: Unmap overwrite evlist when event
 terminate

Em Wed, Jun 15, 2016 at 02:23:35AM +0000, Wang Nan escreveu:
> When see POLLERR or POLLHUP, unmap ring buffer from both the main
> evlist and overwrite evlist.

When you use an auxiliary evlist this makes evlist->parent be different
than evlist, right? So can't we just hide this from tools and do it all
in perf_evlist__filter_pollfd?

This way we will not need to expose perf_evlist__mmap_put(), etc.

I haven't tried to _actually_ do this, just asking from browsing the
patchkit and with the goal of hiding the internals of this thing inside
evlist.c as much as possible.

- Arnaldo
 
> Signed-off-by: Wang Nan <wangnan0@...wei.com>
> Cc: He Kuang <hekuang@...wei.com>
> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Masami Hiramatsu <mhiramat@...nel.org>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Zefan Li <lizefan@...wei.com>
> Cc: pi3orama@....com
> ---
>  tools/perf/builtin-record.c | 30 +++++++++++++++++++++---------
>  tools/perf/util/evlist.c    |  3 +--
>  tools/perf/util/evlist.h    |  2 +-
>  3 files changed, 23 insertions(+), 12 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index b9094f0..ca6376c 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -914,6 +914,26 @@ out:
>  	return err;
>  }
>  
> +static void record__munmap_filtered(struct fdarray *fda, int fd, void *arg)
> +{
> +	struct record *rec = (struct record *)arg;
> +
> +	perf_evlist__mmap_put(rec->evlist, fda->priv[fd].idx);
> +	if (rec->overwrite_evlist)
> +		perf_evlist__mmap_put(rec->overwrite_evlist, fda->priv[fd].idx);
> +}
> +
> +static int record__filter_pollfd(struct record *rec)
> +{
> +	/*
> +	 * Although we may have auxiliray evlist, there is
> +	 * only one pollfd, so we don't need to filter pollfd
> +	 * for auxiliray evlist.
> +	 */
> +	return fdarray__filter(&rec->evlist->pollfd, POLLERR | POLLHUP,
> +			       record__munmap_filtered, rec);
> +}
> +
>  static int __cmd_record(struct record *rec, int argc, const char **argv)
>  {
>  	int err;
> @@ -1150,15 +1170,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>  				err = 0;
>  			waking++;
>  
> -			/*
> -			 * Although we may have auxiliray evlist, there is
> -			 * only one pollfd, so we don't need to filter pollfd
> -			 * for auxiliray evlist.
> -			 *
> -			 * TODO: if an event is terminated (POLLERR | POLLHUP),
> -			 * unmap mmaps for auxiliray evlist too.
> -			 */
> -			if (perf_evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)
> +			if (record__filter_pollfd(rec) == 0)
>  				draining = true;
>  		}
>  
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index e8fcb22..d43ee81 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -27,7 +27,6 @@
>  #include <linux/log2.h>
>  #include <linux/err.h>
>  
> -static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
>  static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx);
>  
>  #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
> @@ -863,7 +862,7 @@ static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)
>  	atomic_inc(&evlist->mmap[idx].refcnt);
>  }
>  
> -static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx)
> +void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx)
>  {
>  	struct perf_mmap *md = &evlist->mmap[idx];
>  
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 41e65ac..ba5e006 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -141,7 +141,7 @@ union perf_event *perf_evlist__mmap_read_backward(struct perf_evlist *evlist,
>  void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx);
>  
>  void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx);
> -
> +void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
>  int perf_evlist__pause(struct perf_evlist *evlist);
>  int perf_evlist__resume(struct perf_evlist *evlist);
>  int perf_evlist__open(struct perf_evlist *evlist);
> -- 
> 1.8.3.4