Steven Rostedt
3d0833953e
ftrace: dynamic enabling/disabling of function calls ...
This patch adds a feature to dynamically replace the ftrace code
with the jmps to allow a kernel with ftrace configured to run
as fast as it can without it configured.
The way this works, is on bootup (if ftrace is enabled), a ftrace
function is registered to record the instruction pointer of all
places that call the function.
Later, if there's still any code to patch, a kthread is awoken
(rate limited to at most once a second) that performs a stop_machine,
and replaces all the code that was called with a jmp over the call
to ftrace. It only replaces what was found the previous time. Typically
the system reaches equilibrium quickly after bootup and there's no code
patching needed at all.
e.g.
call ftrace /* 5 bytes */
is replaced with
jmp 3f /* jmp is 2 bytes and we jump 3 forward */
3:
When we want to enable ftrace for function tracing, the IP recording
is removed, and stop_machine is called again to replace all the locations
of that were recorded back to the call of ftrace. When it is disabled,
we replace the code back to the jmp.
Allocation is done by the kthread. If the ftrace recording function is
called, and we don't have any record slots available, then we simply
skip that call. Once a second a new page (if needed) is allocated for
recording new ftrace function calls. A large batch is allocated at
boot up to get most of the calls there.
Because we do this via stop_machine, we don't have to worry about another
CPU executing a ftrace call as we modify it. But we do need to worry
about NMI's so all functions that might be called via nmi must be
annotated with notrace_nmi. When this code is configured in, the NMI code
will not call notrace.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23 20:33:09 +02:00
genirq: reenable a nobody cared disabled irq when a new driver arrives
2008-05-02 13:40:34 +02:00
Merge branches 'release', 'acpica', 'bugzilla-10224', 'bugzilla-9772', 'bugzilla-9916', 'ec', 'eeepc', 'idle', 'misc', 'pm-legacy', 'sysfs-links-2.6.26', 'thermal', 'thinkpad' and 'video' into release
2008-04-30 13:58:00 -04:00
clocksource: allow read access to available/current_clocksource
2008-05-03 18:11:48 +02:00
ftrace: dynamic enabling/disabling of function calls
2008-05-23 20:33:09 +02:00
[patch 1/1] audit_send_reply(): fix error-path memory leak
2008-05-17 03:30:22 -04:00
[PATCH 1/2] audit: move extern declarations to audit.h
2008-04-28 06:28:04 -04:00
[PATCH] list_for_each_rcu must die: audit
2008-05-17 03:30:23 -04:00
Merge branch 'audit.b50' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
2008-04-29 11:41:22 -07:00
[PATCH] new predicate - AUDIT_FILETYPE
2008-04-28 06:28:37 -04:00
Add kbuild.h that contains common definitions for kbuild users
2008-04-29 08:06:29 -07:00
mm: bdi: add separate writeback accounting capability
2008-04-30 08:29:50 -07:00
CGroup API files: move "releasable" to cgroup_debug subsystem
2008-04-29 08:06:09 -07:00
ntp: support for TAI
2008-05-01 08:03:59 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
kernel: replace remaining __FUNCTION__ occurrences
2008-04-30 08:29:54 -07:00
Fix cpuset sched_relax_domain_level control file
2008-05-08 10:46:56 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
[PATCH] split linux/file.h
2008-05-01 13:08:16 -04:00
ftrace: trace irq disabled critical timings
2008-05-23 20:32:46 +02:00
Removal of FUTEX_FD
2008-05-05 08:18:45 -07:00
hrtimer: remove duplicate helper function
2008-05-03 18:11:48 +02:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
kexec: make extended crashkernel= syntax less confusing
2008-05-01 08:04:00 -07:00
lib: create common ascii hex array
2008-05-14 19:11:14 -07:00
[PATCH] split linux/file.h
2008-05-01 13:08:16 -04:00
kprobes: add (un)register_jprobes for batch registration
2008-04-28 08:58:32 -07:00
Deprecate find_task_by_pid()
2008-04-30 08:29:48 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
ftrace: trace irq disabled critical timings
2008-05-23 20:32:46 +02:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
ftrace: latency tracer infrastructure
2008-05-23 20:32:06 +02:00
make marker_debug static
2008-04-30 08:29:49 -07:00
module: don't ignore vermagic string if module doesn't have modversions
2008-05-09 07:45:18 -07:00
ipc: re-enable msgmni automatic recomputing msgmni if set to negative
2008-04-29 08:06:13 -07:00
cgroups: kernel/ns_cgroup.c should #include <linux/nsproxy.h>
2008-04-29 08:06:07 -07:00
ipc: sysvsem: refuse clone(CLONE_SYSVSEM|CLONE_NEWIPC)
2008-04-29 08:06:14 -07:00
Taint kernel after WARN_ON(condition)
2008-04-29 08:05:59 -07:00
pids: introduce change_pid() helper
2008-04-30 08:29:48 -07:00
pidns: make pid->level and pid_ns->level unsigned
2008-04-30 08:29:49 -07:00
remove div_long_long_rem
2008-05-01 08:03:58 -07:00
signals: join send_sigqueue() with send_group_sigqueue()
2008-04-30 08:29:36 -07:00
ftrace: trace irq disabled critical timings
2008-05-23 20:32:46 +02:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
make generic sys_ptrace unconditional
2008-05-01 10:21:54 -07:00
generic: reduce stack pressure in sched_affinity
2008-04-19 19:44:59 +02:00
kernel: explicitly include required header files under kernel/
2008-04-29 08:06:04 -07:00
Revert "relay: fix splice problem"
2008-05-08 14:06:19 +02:00
memcgroup: add the max_usage member on the res_counter
2008-04-29 08:06:10 -07:00
kernel: use non-racy method for proc entries creation
2008-04-29 08:06:22 -07:00
ftrace: trace preempt off critical timings
2008-05-23 20:32:54 +02:00
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2008-05-05 23:56:18 +02:00
sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
2008-05-05 23:56:18 +02:00
sched: fix weight calculations
2008-05-08 17:00:42 +02:00
sched: /debug/sched_features
2008-04-19 19:45:00 +02:00
sched: make rt_sched_class, idle_sched_class static
2008-05-05 23:56:17 +02:00
sched: fix RT task-wakeup logic
2008-05-05 23:56:18 +02:00
cpumask: use new cpus_scnprintf function
2008-04-19 19:44:59 +02:00
Revert "semaphore: fix"
2008-05-10 20:43:22 -07:00
signals: add set_restore_sigmask
2008-04-30 08:29:37 -07:00
Fix cpu hotplug problem in softirq code
2008-05-01 08:03:58 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/juhl/trivial
2008-04-21 16:36:46 -07:00
pids: sys_getpgid: fix unsafe *pid usage, s/tasklist/rcu/
2008-04-30 08:29:49 -07:00
[PATCH] avoid multiplication overflows and signedness issues for max_fds
2008-05-16 17:22:52 -04:00
Use find_task_by_vpid in taskstats
2008-04-30 08:29:48 -07:00
Make constants in kernel/timeconst.h fixed 64 bits
2008-05-02 16:18:42 -07:00
Make constants in kernel/timeconst.h fixed 64 bits
2008-05-02 16:18:42 -07:00
debugobjects: add timer specific object debugging code
2008-04-30 08:29:53 -07:00
alloc_uid: cleanup
2008-04-30 08:29:53 -07:00
eCryptfs: make key module subsystem respect namespaces
2008-04-29 08:06:07 -07:00
kernel: explicitly include required header files under kernel/
2008-04-29 08:06:04 -07:00
workqueue: remove redundant function invocation
2008-05-01 08:04:02 -07:00
3d0833953e