linux/kernel/trace
Steven Rostedt (Red Hat) d840f718d2 tracing: Init current_trace to nop_trace and remove NULL checks
On early boot up, when the ftrace ring buffer is initialized, the
static variable current_trace is initialized to &nop_trace.
Before this initialization, current_trace is NULL and will never
become NULL again. It is always reassigned to a ftrace tracer.

Several places check if current_trace is NULL before it uses
it, and this check is frivolous, because at the point in time
when the checks are made the only way current_trace could be
NULL is if ftrace failed its allocations at boot up, and the
paths to these locations would probably not be possible.

By initializing current_trace to &nop_trace where it is declared,
current_trace will never be NULL, and we can remove all these
checks of current_trace being NULL which never needed to be
checked in the first place.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-02-01 18:38:47 -05:00
..
blktrace.c tracing: Use this_cpu_ptr per-cpu helper 2013-01-21 13:22:30 -05:00
ftrace.c tracing: Avoid unnecessary multiple recursion checks 2013-01-22 23:38:01 -05:00
Kconfig tracing: Make a snapshot feature available from userspace 2013-01-30 11:02:06 -05:00
Makefile trace: Stop compiling in trace_clock unconditionally 2012-09-13 22:52:08 -04:00
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: Add stats field for amount read from trace ring buffer 2013-01-30 11:01:53 -05:00
rpm-traces.c PM / Runtime: Introduce trace points for tracing rpm_* functions 2011-09-27 22:53:27 +02:00
trace_branch.c tracing: Cache comms only after an event occurred 2012-10-31 16:45:31 -04:00
trace_clock.c tracing: Use sched_clock_cpu for trace_clock_global 2013-01-30 11:02:05 -05:00
trace_entries.h Merge branch 'tip/perf/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent 2012-03-24 08:19:09 +01:00
trace_event_perf.c perf/core improvements and fixes: 2012-08-21 11:27:00 +02:00
trace_events_filter_test.h tracing/filter: Add startup tests for events filter 2011-08-19 14:35:59 -04:00
trace_events_filter.c tracing: Replace strict_strto* with kstrto* 2012-10-31 16:45:23 -04:00
trace_events.c tracing: Remove the extra 4 bytes of padding in events 2013-01-21 21:05:41 -05:00
trace_export.c tracing: Do not enable function event with enable 2012-05-10 15:55:43 -04:00
trace_functions_graph.c tracing/fgraph: Adjust fgraph depth before calling trace return callback 2013-01-29 17:30:31 -05:00
trace_functions.c tracing: Fix unsigned int compare of zero in recursion check 2013-01-24 07:52:34 -05:00
trace_irqsoff.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-12-13 12:00:02 -08:00
trace_kdb.c kdb,ftdump: Remove reference to internal kdb include 2010-10-22 15:34:11 -05:00
trace_kprobe.c tracing: Use irq_work for wake ups and remove *_nowake_*() functions 2012-11-02 10:21:52 -04:00
trace_mmiotrace.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
trace_nop.c
trace_output.c tracing: Format non-nanosec times from tsc clock without a decimal point. 2012-11-13 15:48:40 -05:00
trace_output.h tracing: Allow events to share their print functions 2010-05-14 14:20:32 -04:00
trace_printk.c tracing: Add percpu buffers for trace_printk() 2012-04-23 21:15:55 -04:00
trace_probe.c tracing: Replace strict_strto* with kstrto* 2012-10-31 16:45:23 -04:00
trace_probe.h tracing: Provide trace events interface for uprobes 2012-05-07 14:30:17 +02:00
trace_sched_switch.c tracing: Use irq_work for wake ups and remove *_nowake_*() functions 2012-11-02 10:21:52 -04:00
trace_sched_wakeup.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-12-13 12:00:02 -08:00
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: Fix function tracing recursion self test 2013-01-22 23:37:58 -05:00
trace_stack.c tracing: Remove unneeded checks from the stack tracer 2012-11-19 15:07:13 -05:00
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: Make local functions static 2013-01-21 13:22:31 -05:00
trace_uprobe.c tracing: Verify target file before registering a uprobe event 2013-01-21 13:22:31 -05:00
trace.c tracing: Init current_trace to nop_trace and remove NULL checks 2013-02-01 18:38:47 -05:00
trace.h tracing: Make a snapshot feature available from userspace 2013-01-30 11:02:06 -05:00