linux-kernel - Re: [PATCH v15 09/12] perf record: Read from overwritable ring buffer

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Date:	Wed, 13 Jul 2016 16:07:01 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	Wang Nan <wangnan0@...wei.com>
Cc:	acme@...nel.org, lizefan@...wei.com, linux-kernel@...r.kernel.org,
	pi3orama@....com, He Kuang <hekuang@...wei.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Nilay Vaish <nilayvaish@...il.com>
Subject: Re: [PATCH v15 09/12] perf record: Read from overwritable ring buffer

On Tue, Jul 12, 2016 at 10:00:09AM +0000, Wang Nan wrote:

SNIP

> @@ -131,9 +156,10 @@ rb_find_range(void *data, int mask, u64 head, u64 old,
>  	return backward_rb_find_range(data, mask, head, start, end);
>  }
>  
> -static int record__mmap_read(struct record *rec, struct perf_evlist *evlist, int idx)
> +static int
> +record__mmap_read(struct record *rec, struct perf_mmap *md,
> +		  bool overwrite, bool backward)
>  {
> -	struct perf_mmap *md = &evlist->mmap[idx];
>  	u64 head = perf_mmap__read_head(md);
>  	u64 old = md->prev;
>  	u64 end = head, start = old;
> @@ -143,7 +169,7 @@ static int record__mmap_read(struct record *rec, struct perf_evlist *evlist, int
>  	int rc = 0;
>  
>  	if (rb_find_range(data, md->mask, head,
> -			  old, &start, &end, false))
> +			  old, &start, &end, backward))
>  		return -1;
>  
>  	if (start == end)
> @@ -156,7 +182,7 @@ static int record__mmap_read(struct record *rec, struct perf_evlist *evlist, int
>  		WARN_ONCE(1, "failed to keep up with mmap data. (warn only once)\n");
>  
>  		md->prev = head;
> -		perf_evlist__mmap_consume(evlist, idx);
> +		perf_mmap__consume(md, overwrite || backward);
>  		return 0;
>  	}
>  
> @@ -181,7 +207,7 @@ static int record__mmap_read(struct record *rec, struct perf_evlist *evlist, int
>  	}
>  
>  	md->prev = head;
> -	perf_evlist__mmap_consume(evlist, idx);
> +	perf_mmap__consume(md, overwrite || backward);
>  out:
>  	return rc;
>  }
> @@ -341,6 +367,75 @@ int auxtrace_record__snapshot_start(struct auxtrace_record *itr __maybe_unused)

could above hunks be moved into separate patch?

jirka