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SubjectRe: [RFC PATCH 1/3] perf probe: Init symbol as kprobe if any pev is kprobe
On 2015/06/25 19:37, Wang Nan wrote:
> Before this patch, add_perf_probe_events() init symbol maps only for
> uprobe if the first pev passed to it is a uprobe event. However, with
> the incoming BPF uprobe support, now it will be possible to pass an
> array with combined kprobe and uprobe events to add_perf_probe_events().

This description is not correct. Actually, add_perf_probe_events already
supports mix of uprobes and kprobes. However, from the command line syntax
constrains the first elements of the probe_event arrays must be kprobes.
So, if the array starts with uprobes, no kprobes should be there.

>
> This patch check all pevs instead of the first one, and init kernel
> symbol if any events is not uprobe.

Anyway, I prefer to call init_symbol_maps() with "false" :)

Thank you,

>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> ---
> tools/perf/util/probe-event.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index b386d2f..a2b3026 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2802,8 +2802,21 @@ int cleanup_perf_probe_event(struct perf_probe_event *pev)
> int add_perf_probe_events(struct perf_probe_event *pevs, int npevs, bool cleanup)
> {
> int i, ret;
> + bool user_only = true;
>
> - ret = init_symbol_maps(pevs->uprobes);
> + /* If any pev is kprobe, init kernel symbols. */
> + for (i = 0; i < npevs; i++) {
> + if (!pevs[i].uprobes) {
> + user_only = false;
> + break;
> + }
> + }
> +
> + /*
> + * Compiler can drop user_only:
> + * ret = init_symbol_maps(i >= npevs);
> + */
> + ret = init_symbol_maps(user_only);
> if (ret < 0)
> return ret;
>
>


--
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu.pt@hitachi.com


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