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    tracing: Pushdown the bkl tracepoints calls · 925936eb
    Frederic Weisbecker 提交于
    Currently we are calling the bkl tracepoint callbacks just before the
    bkl lock/unlock operations, ie the tracepoint call is not inside a
    lock_kernel() function but inside a lock_kernel() macro. Hence the
    bkl trace event header must be included from smp_lock.h. This raises
    some nasty circular header dependencies:
    
    linux/smp_lock.h -> trace/events/bkl.h -> trace/define_trace.h
    -> trace/ftrace.h -> linux/ftrace_event.h -> linux/hardirq.h
    -> linux/smp_lock.h
    
    This results in incomplete event declarations, spurious event
    definitions and other kind of funny behaviours.
    
    This is hardly fixable without ugly workarounds. So instead, we push
    the file name, line number and function name as lock_kernel()
    parameters, so that we only deal with the trace event header from
    lib/kernel_lock.c
    
    This adds two parameters to lock_kernel() and unlock_kernel() but
    it should be fine wrt to performances because this pair dos not seem
    to be called in fast paths.
    Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Li Zefan <lizf@cn.fujitsu.com>
    925936eb
smp_lock.h 1.6 KB