Re: [PATCH v2 5/9] libperf: Add support for user space counter access

[Jiri Olsa]

On Fri, Aug 28, 2020 at 02:56:10PM -0600, Rob Herring wrote:

SNIP

>  
> +void *perf_evsel__mmap(struct perf_evsel *evsel)
> +{
> +	int ret;
> +	struct perf_mmap *map;
> +	struct perf_mmap_param mp = {
> +		.mask = -1,
> +		.prot = PROT_READ | PROT_WRITE,
> +	};
> +
> +	if (FD(evsel, 0, 0) < 0)
> +		return NULL;
> +
> +	map = zalloc(sizeof(*map));
> +	if (!map)
> +		return NULL;
> +
> +	perf_mmap__init(map, NULL, false, NULL);
> +
> +	ret = perf_mmap__mmap(map, &mp, FD(evsel, 0, 0), 0);
> +	if (ret) {
> +		free(map);
> +		return NULL;
> +	}
> +
> +	evsel->mmap = map;
> +	return map->base;
> +}

so this only maps first page, I think we should use different
name and keep perf_evsel__mmap for some generic map with size

perf_evsel__mmap_user
perf_evsel__mmap_zero
...?

not sure.. or we could add size argument

jirka