On Sun, 11 Oct 2020 00:28:09 +0900
Masami Hiramatsu <mhira...@kernel.org> wrote:
> Add ftrace.instance.*.alloc_snapshot option.
>
> This option has been described in Documentation/trace/boottime-trace.rst
> but not implemented yet.
>
> ftrace.[instance.INSTANCE.]alloc_snapshot
> Allocate snapshot buffer.
>
> The difference from kernel.alloc_snapshot is that the kernel.alloc_snapshot
> will allocate the buffer only for the main instance, but this can allocate
> buffer for any new instances.
I queued this up. Thanks Masami!
-- Steve
>
> Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
> ---
> kernel/trace/trace_boot.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
> index 754e3cf2df3a..c22a152ef0b4 100644
> --- a/kernel/trace/trace_boot.c
> +++ b/kernel/trace/trace_boot.c
> @@ -284,6 +284,12 @@ trace_boot_enable_tracer(struct trace_array *tr, struct
> xbc_node *node)
> if (tracing_set_tracer(tr, p) < 0)
> pr_err("Failed to set given tracer: %s\n", p);
> }
> +
> + /* Since tracer can free snapshot buffer, allocate snapshot here.*/
> + if (xbc_node_find_value(node, "alloc_snapshot", NULL)) {
> + if (tracing_alloc_snapshot_instance(tr) < 0)
> + pr_err("Failed to allocate snapshot buffer\n");
> + }
> }
>
> static void __init
