mk-rootfs.sh

hc

2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376

 kernel/Documentation/trace/tracepoints.rst
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@@ -146,3 +146,30 @@
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       define tracepoints. Check http://lwn.net/Articles/379903,
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       http://lwn.net/Articles/381064 and http://lwn.net/Articles/383362
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       for a series of articles with more details.
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+
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+If you require calling a tracepoint from a header file, it is not
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+recommended to call one directly or to use the trace_<tracepoint>_enabled()
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+function call, as tracepoints in header files can have side effects if a
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+header is included from a file that has CREATE_TRACE_POINTS set, as
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+well as the trace_<tracepoint>() is not that small of an inline
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+and can bloat the kernel if used by other inlined functions. Instead,
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+include tracepoint-defs.h and use tracepoint_enabled().
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+
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+In a C file::
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+
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+	void do_trace_foo_bar_wrapper(args)
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+	{
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+		trace_foo_bar(args);
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+	}
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+
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+In the header file::
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+
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+	DECLARE_TRACEPOINT(foo_bar);
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+
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+	static inline void some_inline_function()
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+	{
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+		[..]
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+		if (tracepoint_enabled(foo_bar))
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+			do_trace_foo_bar_wrapper(args);
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+		[..]
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+	}