Steven Rostedt 4376cac667 ftrace: Do not disable interrupts for modules in mcount update ... When I mounted an NFS directory, it caused several modules to be loaded. At the time I was running the preemptirqsoff tracer, and it showed the following output: # tracer: preemptirqsoff # # preemptirqsoff latency trace v1.1.5 on 2.6.33.9-rt30-mrg-test # -------------------------------------------------------------------- # latency: 1177 us, #4/4, CPU#3 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: modprobe-19370 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # => started at: ftrace_module_notify # => ended at: ftrace_module_notify # # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| /_--=> lock-depth # |||||/ delay # cmd pid |||||| time | caller # \ / |||||| \ | / modprobe-19370 3d.... 0us!: ftrace_process_locs <-ftrace_module_notify modprobe-19370 3d.... 1176us : ftrace_process_locs <-ftrace_module_notify modprobe-19370 3d.... 1178us : trace_hardirqs_on <-ftrace_module_notify modprobe-19370 3d.... 1178us : <stack trace> => ftrace_process_locs => ftrace_module_notify => notifier_call_chain => __blocking_notifier_call_chain => blocking_notifier_call_chain => sys_init_module => system_call_fastpath That's over 1ms that interrupts are disabled on a Real-Time kernel! Looking at the cause (being the ftrace author helped), I found that the interrupts are disabled before the code modification of mcounts into nops. The interrupts only need to be disabled on start up around this code, not when modules are being loaded. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2011-07-07 22:39:38 -04:00
..
blktrace.c	block: make unplug timer trace event correspond to the schedule() unplug	2011-04-16 13:51:05 +02:00
ftrace.c	ftrace: Do not disable interrupts for modules in mcount update	2011-07-07 22:39:38 -04:00
Kconfig	ftrace: Build without frame pointers on Microblaze	2011-04-21 09:06:24 -04:00
Makefile	tracing: Fix TRACE_EVENT power tracepoint creation	2011-01-07 23:26:29 -05:00
power-traces.c	perf: Clean up power events by introducing new, more generic ones	2011-01-04 08:16:54 +01:00
ring_buffer_benchmark.c	tracing: Use NUMA allocation for per-cpu ring buffer pages	2011-06-14 22:04:39 -04:00
ring_buffer.c	ring-buffer: Set __GFP_NORETRY flag for ring buffer allocating process	2011-06-14 22:48:51 -04:00
trace_branch.c	tracing: Allow events to share their print functions	2010-05-14 14:20:32 -04:00
trace_clock.c	Fix common misspellings	2011-03-31 11:26:23 -03:00
trace_entries.h	Fix common misspellings	2011-03-31 11:26:23 -03:00
trace_event_perf.c	tracing: New flag to allow non privileged users to use a trace event	2010-11-18 14:37:40 +01:00
trace_events_filter.c	trace, filters: Initialize the match variable in process_ops() properly	2011-03-18 14:41:27 +01:00
trace_events.c	tracing: Convert to kstrtoul_from_user	2011-06-14 22:48:50 -04:00
trace_export.c	tracing: Replace trace_event struct array with pointer array	2011-02-02 21:37:13 -05:00
trace_functions_graph.c	tracing: Still trace filtered irq functions when irq trace is disabled	2011-07-07 22:26:27 -04:00
trace_functions.c	ftrace: Implement separate user function filtering	2011-05-18 15:29:50 -04:00
trace_irqsoff.c	tracing, function_graph: Remove dependency of abstime and duration fields on latency	2011-06-14 22:48:47 -04:00
trace_kdb.c	kdb,ftdump: Remove reference to internal kdb include	2010-10-22 15:34:11 -05:00
trace_kprobe.c	Merge branch 'tip/perf/core-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core	2011-07-05 11:55:43 +02:00
trace_mmiotrace.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
trace_nop.c
trace_output.c	tracing: Add __print_symbolic_u64 to avoid warnings on 32bit machine	2011-05-25 22:13:44 -04:00
trace_output.h	tracing: Allow events to share their print functions	2010-05-14 14:20:32 -04:00
trace_printk.c	tracing: Fix regression in printk_formats file	2011-06-09 08:42:15 -04:00
trace_sched_switch.c	tracing: Remove obsolete sched_switch tracer	2011-02-08 17:14:56 -05:00
trace_sched_wakeup.c	tracing, function_graph: Remove dependency of abstime and duration fields on latency	2011-06-14 22:48:47 -04:00
trace_selftest_dynamic.c	ftrace: Add self-tests for multiple function trace users	2011-05-18 19:24:51 -04:00
trace_selftest.c	ftrace: Add self-tests for multiple function trace users	2011-05-18 19:24:51 -04:00
trace_stack.c	tracing: Convert to kstrtoul_from_user	2011-06-14 22:48:50 -04:00
trace_stat.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
trace_stat.h
trace_syscalls.c	tracing/syscalls: Early terminate search for sys_ni_syscall	2011-02-07 21:30:14 -05:00
trace_workqueue.c	jump label: Initialize workqueue tracepoints *before* they are registered	2010-09-22 16:30:03 -04:00
trace.c	tracing/kprobes: Fix kprobe-tracer to support stack trace	2011-06-14 22:48:53 -04:00
trace.h	tracing: Still trace filtered irq functions when irq trace is disabled	2011-07-07 22:26:27 -04:00