Steven Rostedt a63ce5b306 tracing: Buffer the output of seq_file in case of filled buffer ... If the seq_read fills the buffer it will call s_start again on the next itertation with the same position. This causes a problem with the function_graph tracer because it consumes the iteration in order to determine leaf functions. What happens is that the iterator stores the entry, and the function graph plugin will look at the next entry. If that next entry is a return of the same function and task, then the function is a leaf and the function_graph plugin calls ring_buffer_read which moves the ring buffer iterator forward (the trace iterator still points to the function start entry). The copying of the trace_seq to the seq_file buffer will fail if the seq_file buffer is full. The seq_read will not show this entry. The next read by userspace will cause seq_read to again call s_start which will reuse the trace iterator entry (the function start entry). But the function return entry was already consumed. The function graph plugin will think that this entry is a nested function and not a leaf. To solve this, the trace code now checks the return status of the seq_printf (trace_print_seq). If the writing to the seq_file buffer fails, we set a flag in the iterator (leftover) and we do not reset the trace_seq buffer. On the next call to s_start, we check the leftover flag, and if it is set, we just reuse the trace_seq buffer and do not call into the plugin print functions. Before this patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) | __fsnotify_parent() { 2) 0.540 us | inotify_dentry_parent_queue_event(); After the patch: 2) | fput() { 2) | __fput() { 2) 0.550 us | inotify_inode_queue_event(); 2) 0.548 us | __fsnotify_parent(); 2) 0.540 us | inotify_dentry_parent_queue_event(); [ Updated the patch to fix a missing return 0 from the trace_print_seq() stub when CONFIG_TRACING is disabled. Reported-by: Ingo Molnar <mingo@elte.hu> ] Reported-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2009-12-09 13:55:26 -05:00
..
gcov	microblaze: Enable GCOV_PROFILE_ALL	2009-09-21 14:29:21 +02:00
irq	Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 09:53:08 -08:00
power	PM / Hibernate: Add newline to load_image() fail path	2009-11-03 11:03:09 +01:00
time	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
trace	tracing: Buffer the output of seq_file in case of filled buffer	2009-12-09 13:55:26 -05:00
.gitignore
acct.c	bsdacct: switch credentials for writing to the accounting file	2009-08-24 11:33:40 +10:00
async.c	async: Fix lack of boot-time console due to insufficient synchronization	2009-06-08 12:31:53 -07:00
audit.c	Audit: send signal info if selinux is disabled	2009-09-24 03:50:26 -04:00
audit.h	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
audit_tree.c	Fix rule eviction order for AUDIT_DIR	2009-06-24 00:02:38 -04:00
audit_watch.c	Audit: reorganize struct audit_watch to save 8 bytes	2009-09-24 03:50:25 -04:00
auditfilter.c	Audit: clean up all op= output to include string quoting	2009-06-24 00:00:52 -04:00
auditsc.c	Audit: rearrange audit_context to save 16 bytes per struct	2009-09-24 03:50:26 -04:00
backtracetest.c
bounds.c
capability.c	remove CONFIG_SECURITY_FILE_CAPABILITIES compile option	2009-11-24 15:06:47 +11:00
cgroup.c	cgroup: fix strstrip() misuse	2009-10-29 07:39:25 -07:00
cgroup_freezer.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
compat.c
configs.c
cpu.c	Merge branch 'x86-pat-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-09-15 09:19:38 -07:00
cpuset.c	cpumask: Partition_sched_domains takes array of cpumask_var_t	2009-11-04 13:16:40 +01:00
cred-internals.h
cred.c	creds_are_invalid() needs to be exported for use by modules:	2009-09-23 11:02:26 -07:00
delayacct.c	headers: taskstats_kern.h trim	2009-09-18 09:48:52 -07:00
dma.c
exec_domain.c
exit.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:49 -08:00
extable.c
fork.c	sched, cputime: Introduce thread_group_times()	2009-12-02 17:32:40 +01:00
freezer.c	sched: fix nr_uninterruptible accounting of frozen tasks really	2009-07-18 14:19:53 +02:00
futex.c	futex: Fix spurious wakeup for requeue_pi really	2009-10-28 20:34:34 +01:00
futex_compat.c	futex: Fix compat_futex to be same as futex for REQUEUE_PI	2009-08-10 15:41:12 +02:00
groups.c	groups: move code to kernel/groups.c	2009-06-16 19:47:48 -07:00
hrtimer.c	Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-05 12:04:16 -07:00
hung_task.c	softlockup: Fix hung_task_check_count sysctl	2009-11-27 06:21:57 +01:00
hw_breakpoint.c	hw-breakpoints: Use struct perf_event_attr to define kernel breakpoints	2009-11-27 06:22:59 +01:00
itimer.c	itimers: Add tracepoints for itimer	2009-08-29 14:10:07 +02:00
kallsyms.c	hw-breakpoints: Fix broken hw-breakpoint sample module	2009-11-10 11:23:29 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks	mutex: Better control mutex adaptive spinning config	2009-12-03 11:50:11 +01:00
Kconfig.preempt
kexec.c	kexec: fix omitting offset in extended crashkernel syntax	2009-07-29 19:10:34 -07:00
kfifo.c	kfifo: Use "const" definitions	2009-09-19 13:13:17 -07:00
kgdb.c	sched: Remove unused __schedule() declaration	2009-11-04 11:43:42 +01:00
kmod.c	security: report the module name to security_module_request	2009-11-10 09:33:46 +11:00
kprobes.c	Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:21 -08:00
ksysfs.c
kthread.c	sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.c	2009-11-03 07:25:00 +01:00
latencytop.c
lockdep.c	tracing: Rename 'lockdep' event subsystem into 'lock'	2009-11-13 10:48:27 +01:00
lockdep_internals.h	lockdep: BFS cleanup	2009-07-24 10:53:29 +02:00
lockdep_proc.c	seq_file: constify seq_operations	2009-09-23 07:39:29 -07:00
lockdep_states.h
Makefile	Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:21 -08:00
module.c	modules: don't export section names of empty sections via sysfs	2009-12-02 15:38:25 -08:00
mutex-debug.c	headers: remove sched.h from interrupt.h	2009-10-11 11:20:58 -07:00
mutex-debug.h
mutex.c	mutex: Better control mutex adaptive spinning config	2009-12-03 11:50:11 +01:00
mutex.h
notifier.c	kprobes: Fix to add __kprobes to notify_die	2009-08-30 03:08:26 +02:00
ns_cgroup.c	cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time	2009-09-24 07:20:58 -07:00
nsproxy.c	nsproxy: extract create_nsproxy()	2009-06-18 13:03:56 -07:00
panic.c	Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-10-08 12:16:35 -07:00
params.c	param: fix setting arrays of bool	2009-10-29 08:56:20 +10:30
perf_event.c	perf: Don't free perf_mmap_data until work has been done	2009-12-02 09:30:18 +01:00
pid.c	mm: also use alloc_large_system_hash() for the PID hash table	2009-09-22 07:17:38 -07:00
pid_namespace.c	pidns: deny CLONE_PARENT|CLONE_NEWPID combination	2009-09-24 07:21:04 -07:00
pm_qos_params.c
posix-cpu-timers.c	itimers: Add tracepoints for itimer	2009-08-29 14:10:07 +02:00
posix-timers.c	time: Introduce CLOCK_REALTIME_COARSE	2009-08-21 21:43:46 +02:00
printk.c	Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 09:50:22 -08:00
profile.c	kernel/profile.c: Switch /proc/irq/prof_cpu_mask to seq_file	2009-09-20 20:15:40 +02:00
ptrace.c	ptrace: __ptrace_detach: do __wake_up_parent() if we reap the tracee	2009-09-24 07:20:59 -07:00
rcupdate.c	rcu: Re-arrange code to reduce #ifdef pain	2009-11-22 18:58:16 +01:00
rcutiny.c	rcu: Eliminate unneeded function wrapping	2009-11-22 18:58:16 +01:00
rcutorture.c	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree.c	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree.h	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree_plugin.h	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
rcutree_trace.c	rcu: Add expedited grace-period support for preemptible RCU	2009-12-03 11:35:25 +01:00
relay.c	const: mark struct vm_struct_operations	2009-09-27 11:39:25 -07:00
res_counter.c	memcg: some modification to softlimit under hierarchical memory reclaim.	2009-10-01 16:11:13 -07:00
resource.c	walk system ram range	2009-09-23 07:39:41 -07:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c	rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()	2009-08-06 05:50:21 +02:00
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:49 -08:00
sched_clock.c	sched_clock: Fix atomicity/continuity bug by using cmpxchg64()	2009-09-30 22:56:10 +02:00
sched_cpupri.c	sched: Add new prio to cpupri before removing old prio	2009-08-02 14:26:09 +02:00
sched_cpupri.h
sched_debug.c	sched: Rate-limit newidle	2009-11-04 19:13:48 +01:00
sched_fair.c	Merge branch 'sched/urgent' into sched/core	2009-11-26 10:50:42 +01:00
sched_features.h	sched: Add new wakeup preemption mode: WAKEUP_RUNNING	2009-09-17 10:17:25 +02:00
sched_idletask.c	sched: Simplify sys_sched_rr_get_interval() system call	2009-09-21 09:53:55 +02:00
sched_rt.c	cpumask: Simplify sched_rt.c	2009-11-04 13:16:38 +01:00
sched_stats.h
seccomp.c
semaphore.c
signal.c	Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 15:30:21 -08:00
slow-work-debugfs.c	SLOW_WORK: Move slow_work's proc file to debugfs	2009-12-01 08:20:31 -08:00
slow-work.c	SLOW_WORK: Move slow_work's proc file to debugfs	2009-12-01 08:20:31 -08:00
slow-work.h	SLOW_WORK: Move slow_work's proc file to debugfs	2009-12-01 08:20:31 -08:00
smp.c	generic-ipi: Add smp_call_function_any()	2009-11-18 14:52:25 +01:00
softirq.c	rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls	2009-11-02 16:06:37 +01:00
softlockup.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
spinlock.c	locking: Reduce ifdefs in kernel/spinlock.c	2009-11-13 20:53:28 +01:00
srcu.c	rcu: Add synchronize_srcu_expedited()	2009-10-26 09:40:30 +01:00
stacktrace.c
stop_machine.c
sys.c	sched, cputime: Introduce thread_group_times()	2009-12-02 17:32:40 +01:00
sys_ni.c	Merge branch 'master' of /home/davem/src/GIT/linux-2.6/	2009-09-24 15:13:11 -07:00
sysctl.c	Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-12-05 09:50:22 -08:00
sysctl_check.c	sysctl: fix false positives when PROC_SYSCTL=n	2009-10-29 07:39:30 -07:00
taskstats.c	genetlink: make netns aware	2009-07-12 14:03:27 -07:00
test_kprobes.c
time.c	sched, time: Define nsecs_to_jiffies()	2009-11-26 12:59:20 +01:00
timeconst.pl
timer.c	Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2009-09-23 09:46:15 -07:00
tracepoint.c	trivial: fix typo "to to" in multiple files	2009-09-21 15:14:55 +02:00
tsacct.c
uid16.c	headers: utsname.h redux	2009-09-23 18:13:10 -07:00
up.c
user.c	uids: Prevent tear down race	2009-11-02 16:02:39 +01:00
user_namespace.c
utsname.c	utsns: extract creeate_uts_ns()	2009-06-18 13:03:55 -07:00
utsname_sysctl.c	sysctl: remove "struct file *" argument of ->proc_handler	2009-09-24 07:21:04 -07:00
wait.c	locking, sched: Give waitqueue spinlocks their own lockdep classes	2009-08-10 14:43:09 +02:00
workqueue.c	workqueue: fix race condition in schedule_on_each_cpu()	2009-11-17 17:40:33 -08:00