• Steven Rostedt (Red Hat)'s avatar
    tracing: Use flag buffer_disabled for irqsoff tracer · 2fd821ee
    Steven Rostedt (Red Hat) authored
    commit 10246fa35d4ffdfe472185d4cbf9c2dfd9a9f023 upstream.
    
    If the ring buffer is disabled and the irqsoff tracer records a trace it
    will clear out its buffer and lose the data it had previously recorded.
    
    Currently there's a callback when writing to the tracing_of file, but if
    tracing is disabled via the function tracer trigger, it will not inform
    the irqsoff tracer to stop recording.
    
    By using the "mirror" flag (buffer_disabled) in the trace_array, that keeps
    track of the status of the trace_array's buffer, it gives the irqsoff
    tracer a fast way to know if it should record a new trace or not.
    The flag may be a little behind the real state of the buffer, but it
    should not affect the trace too much. It's more important for the irqsoff
    tracer to be fast.
    Reported-by: default avatarDave Jones <davej@redhat.com>
    Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    2fd821ee
trace_irqsoff.c 16.9 KB