tracing/boot: Add ftrace.instance.*.alloc_snapshot option

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.

Link: https://lkml.kernel.org/r/160234368948.400560.15313384470765915015.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2020-10-11 00:28:09 +09:00 committed by Steven Rostedt (VMware)
parent bbeb97464e
commit c163409719

View File

@ -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