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41d9c0becc
There are options that are unique to a specific tracer (like function and function graph). Currently, these options are only visible in the options directory when the tracer is enabled. This has been a pain, especially for something like the func_stack_trace option that if used inappropriately, could bring the system to a crawl. But the only way to see it, is to enable the function tracer. For example, if one had done: # cd /sys/kernel/tracing # echo __schedule > set_ftrace_filter # echo 1 > options/func_stack_trace # echo function > current_tracer The __schedule call will be traced and a stack trace will also be recorded there. Now when you were done, you may do... # echo nop > current_tracer # echo > set_ftrace_filter But you forgot to disable the func_stack_trace. The only way to disable it is to re-enable function tracing first. If you do not add a filter to set_ftrace_filter and just do: # echo function > current_tracer Now you would be performing a stack trace on *every* function! On some systems, that causes a live lock. Others may take a few minutes to fix your mistake. Having the func_stack_trace option visible allows you to check it and disable it before enabling the funtion tracer. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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| .. | ||
| blktrace.c | ||
| bpf_trace.c | ||
| ftrace.c | ||
| Kconfig | ||
| Makefile | ||
| power-traces.c | ||
| ring_buffer.c | ||
| ring_buffer_benchmark.c | ||
| rpm-traces.c | ||
| trace.c | ||
| trace.h | ||
| trace_benchmark.c | ||
| trace_benchmark.h | ||
| trace_branch.c | ||
| trace_clock.c | ||
| trace_entries.h | ||
| trace_event_perf.c | ||
| trace_events.c | ||
| trace_events_filter.c | ||
| trace_events_filter_test.h | ||
| trace_events_trigger.c | ||
| trace_export.c | ||
| trace_functions.c | ||
| trace_functions_graph.c | ||
| trace_irqsoff.c | ||
| trace_kdb.c | ||
| trace_kprobe.c | ||
| trace_mmiotrace.c | ||
| trace_nop.c | ||
| trace_output.c | ||
| trace_output.h | ||
| trace_printk.c | ||
| trace_probe.c | ||
| trace_probe.h | ||
| trace_sched_switch.c | ||
| trace_sched_wakeup.c | ||
| trace_selftest.c | ||
| trace_selftest_dynamic.c | ||
| trace_seq.c | ||
| trace_stack.c | ||
| trace_stat.c | ||
| trace_stat.h | ||
| trace_syscalls.c | ||
| trace_uprobe.c | ||