ftrace: trace_pipe_raw, blocking, and splice()

From: Slava Pestov
Date: Tue Jul 12 2011 - 20:27:45 EST


Hi ftrace users,

I notice that tracing_buffers_splice_read() has this comment in it
around line 3900:

/* TODO: block */

Was the original intention that reading from trace_pipe_raw with
tracing enabled should block if there is no data available, rather
than returning with end of file?

If so, I suggest adding a new trace_raw special file which behaves
like the current trace_pipe_raw (return 0 on EOF). Then we'd change
trace_pipe_raw to block on EOF.

Does this sound reasonable or is breaking APIs like this unacceptable?

Slava
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/