Steven Rostedt 4a0b1665db tracing: Fix irqoff selftest expanding max buffer ... If the kernel command line declares a tracer "ftrace=sometracer" and that tracer is either not defined or is enabled after irqsoff, then the irqs off selftest will fail with the following error: Testing tracer irqsoff: ------------[ cut here ]------------ WARNING: at /home/rostedt/work/autotest/nobackup/linux-test.git/kernel/trace/tra ce.c:713 update_max_tr_single+0xfa/0x11b() Hardware name: Modules linked in: Pid: 1, comm: swapper Not tainted 2.6.38-rc8-test #1 Call Trace: [<c0441d9d>] ? warn_slowpath_common+0x65/0x7a [<c049adb2>] ? update_max_tr_single+0xfa/0x11b [<c0441dc1>] ? warn_slowpath_null+0xf/0x13 [<c049adb2>] ? update_max_tr_single+0xfa/0x11b [<c049e454>] ? stop_critical_timing+0x154/0x204 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049e529>] ? time_hardirqs_on+0x25/0x28 [<c0468bca>] ? trace_hardirqs_on_caller+0x18/0x12f [<c0468cec>] ? trace_hardirqs_on+0xb/0xd [<c049b54b>] ? trace_selftest_startup_irqsoff+0x5b/0xc1 [<c049b6b8>] ? register_tracer+0xf8/0x1a3 [<c14e93fe>] ? init_irqsoff_tracer+0xd/0x11 [<c040115e>] ? do_one_initcall+0x71/0x121 [<c14e93f1>] ? init_irqsoff_tracer+0x0/0x11 [<c14ce3a9>] ? kernel_init+0x13a/0x1b6 [<c14ce26f>] ? kernel_init+0x0/0x1b6 [<c0403842>] ? kernel_thread_helper+0x6/0x10 ---[ end trace e93713a9d40cd06c ]--- .. no entries found ..FAILED! What happens is the "ftrace=..." will expand the ring buffer to its default size (from its minimum size) but it will not expand the max ring buffer (the ring buffer to store maximum latencies). When the irqsoff test runs, it will call the ring buffer swap routine that checks if the max ring buffer is the same size as the normal ring buffer, and will fail if it is not. This causes the test to fail. The solution is to expand the max ring buffer before running the self test if the max ring buffer is used by that tracer and the normal ring buffer is expanded. The max ring buffer should be shrunk again after the test is done to save space. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2011-03-10 10:34:58 -05:00
..
blktrace.c	blktrace: Remove blk_fill_rwbs_rq.	2011-03-03 10:53:20 -05:00
ftrace.c
Kconfig
Makefile
power-traces.c
ring_buffer_benchmark.c
ring_buffer.c	tracing: Explain about unstable clock on resume with ring buffer warning	2011-03-10 10:34:47 -05:00
trace_branch.c
trace_clock.c
trace_entries.h	tracing: Fix event alignment: ftrace:context_switch and ftrace:wakeup	2011-03-10 10:34:16 -05:00
trace_event_perf.c
trace_events_filter.c
trace_events.c	tracing: Export trace_set_clr_event()	2011-03-10 10:34:51 -05:00
trace_export.c
trace_functions_graph.c
trace_functions.c
trace_irqsoff.c
trace_kdb.c
trace_kprobe.c	tracing/kprobe: Fix NULL pointer deref check	2011-02-14 12:09:53 +01:00
trace_mmiotrace.c
trace_nop.c
trace_output.c	tracing: Adjust conditional expression latency formatting.	2011-03-10 10:34:35 -05:00
trace_output.h
trace_printk.c
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest_dynamic.c
trace_selftest.c
trace_stack.c
trace_stat.c
trace_stat.h
trace_syscalls.c
trace_workqueue.c
trace.c	tracing: Fix irqoff selftest expanding max buffer	2011-03-10 10:34:58 -05:00
trace.h	tracing: Align 4 byte ints together in struct tracer	2011-03-10 10:34:54 -05:00