Commit c1634097 authored Oct 11, 2020 by Masami Hiramatsu Committed by Steven Rostedt (VMware) Oct 15, 2020

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>

parent bbeb9746

kernel/trace/trace_boot.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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

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