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H A D | Makefile | 2464a609ded094204a3aed24823745ec58e3c879 Thu Jul 17 10:40:48 CDT 2008 Ingo Molnar <mingo@elte.hu> ftrace: do not trace library functions
make function tracing more robust: do not trace library functions.
We've already got a sizable list of exceptions:
ifdef CONFIG_FTRACE # Do not profile string.o, since it may be used in early boot or vdso CFLAGS_REMOVE_string.o = -pg # Also do not profile any debug utilities CFLAGS_REMOVE_spinlock_debug.o = -pg CFLAGS_REMOVE_list_debug.o = -pg CFLAGS_REMOVE_debugobjects.o = -pg CFLAGS_REMOVE_find_next_bit.o = -pg CFLAGS_REMOVE_cpumask.o = -pg CFLAGS_REMOVE_bitmap.o = -pg endif
... and the pattern has been that random library functionality showed up in ftrace's critical path (outside of its recursion check), causing hard to debug lockups.
So be a bit defensive about it and exclude all lib/*.o functions by default. It's not that they are overly interesting for tracing purposes anyway. Specific ones can still be traced, in an opt-in manner.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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