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* tracing: fix splice return too largeLai Jiangshan2009-04-101-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | I got these from strace: splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 12288 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 16384 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192 splice(0x3, 0, 0x5, 0, 0x1000, 0x1) = 8192 I wanted to splice_read 4096 bytes, but it returns 8192 or larger. It is because the return value of tracing_buffers_splice_read() does not include "zero out any left over data" bytes. But tracing_buffers_read() includes these bytes, we make them consistent. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <49D46674.9030804@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: update file->f_pos when splice(2) itLai Jiangshan2009-04-101-7/+1
| | | | | | | | | | | | | | | | | | | | | | | Impact: Cleanup These two lines: if (unlikely(*ppos)) return -ESPIPE; in tracing_buffers_splice_read() are not needed, VFS layer has disabled seek(2). We remove these two lines, and then we can update file->f_pos. And tracing_buffers_read() updates file->f_pos, this fix make tracing_buffers_splice_read() updates file->f_pos too. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <49D46670.4010503@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: allocate page when neededLai Jiangshan2009-04-101-8/+8
| | | | | | | | | | | | | Impact: Cleanup Sometimes, we open trace_pipe_raw, but we don't read(2) it, we just splice(2) it, thus, the page is not used. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <49D4666B.4010608@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: disable seeking for trace_pipe_rawLai Jiangshan2009-04-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Impact: disable pread() We set tracing_buffers_fops.llseek to no_llseek, but we can still perform pread() to read this file. That is not expected. This fix uses nonseekable_open() to disable it. tracing_buffers_fops.llseek is still set to no_llseek, it mark this file is a "non-seekable device" and is used by sys_splice(). See also do_splice() or manual of splice(2): ERRORS EINVAL Target file system doesn't support splicing; neither of the descriptors refers to a pipe; or offset given for non-seekable device. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <49D46668.8030806@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Update /debug/tracing/READMENikanth Karthikesan2009-04-071-2/+2
| | | | | | | | | | Some of the tracers have been renamed, which was not updated in the in-kernel run-time README file. Update it. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> LKML-Reference: <200903231158.32151.knikanth@suse.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing/ftrace: alloc the started cpumask for the trace fileFrederic Weisbecker2009-04-071-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix a crash while cat trace file Currently we are using a cpumask to remind each cpu where a trace occured. It lets us notice the user that a cpu just had its first trace. But on latest -tip we have the following crash once we cat the trace file: IP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 *pde = 00000000 Oops: 0000 [#1] PREEMPT SMP last sysfs file: /sys/class/net/eth0/carrier Pid: 3897, comm: cat Not tainted (2.6.29-tip-02825-g0f22972-dirty #81) EIP: 0060:[<c0270c4a>] EFLAGS: 00010297 CPU: 0 EIP is at print_trace_fmt+0x45/0xe7 EAX: 00000000 EBX: 00000000 ECX: c12d9e98 EDX: ccdb7010 ESI: d31f4000 EDI: 00322401 EBP: d31f3f10 ESP: d31f3efc DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 Process cat (pid: 3897, ti=d31f2000 task=d3b3cf20 task.ti=d31f2000) Stack: d31f4080 ccdb7010 d31f4000 d691fe70 ccdb7010 d31f3f24 c0270e5c d31f4000 d691fe70 d31f4000 d31f3f34 c02718e8 c12d9e98 d691fe70 d31f3f70 c02bfc33 00001000 09130000 d3b46e00 d691fe98 00000000 00000079 00000001 00000000 Call Trace: [<c0270e5c>] ? print_trace_line+0x170/0x17c [<c02718e8>] ? s_show+0xa7/0xbd [<c02bfc33>] ? seq_read+0x24a/0x327 [<c02bf9e9>] ? seq_read+0x0/0x327 [<c02ab18b>] ? vfs_read+0x86/0xe1 [<c02ab289>] ? sys_read+0x40/0x65 [<c0202d8f>] ? sysenter_do_call+0x12/0x3c Code: 00 00 00 89 45 ec f7 c7 00 20 00 00 89 55 f0 74 4e f6 86 98 10 00 00 02 74 45 8b 86 8c 10 00 00 8b 9e a8 10 00 00 e8 52 f3 ff ff <0f> a3 03 19 c0 85 c0 75 2b 8b 86 8c 10 00 00 8b 9e a8 10 00 00 EIP: [<c0270c4a>] print_trace_fmt+0x45/0xe7 SS:ESP 0068:d31f3efc CR2: 0000000000000000 ---[ end trace aa9cf38e5ebed9dd ]--- This is because we alloc the iter->started cpumask on tracing_pipe_open but not on tracing_open. It hadn't been noticed until now because we need to have ring buffer overruns to activate the starting of cpu buffer detection. Also, we need a check to not print the messagge for the first trace on the file. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1238619188-6109-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing/ftrace: fix missing include string.hFrederic Weisbecker2009-04-071-0/+1
| | | | | | | | | | | | | | | Building a kernel with tracing can raise the following warning on tip/master: kernel/trace/trace.c:1249: error: implicit declaration of function 'vbin_printf' We are missing an include to string.h Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1238160130-7437-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: fix incorrect return type of ns2usecs()Lai Jiangshan2009-04-071-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix time output bug in 32bits system ns2usecs() returns 'long', it's incorrect. (In i386) ... <idle>-0 [000] 521.442100: _spin_lock <-tick_do_update_jiffies64 <idle>-0 [000] 521.442101: do_timer <-tick_do_update_jiffies64 <idle>-0 [000] 521.442102: update_wall_time <-do_timer <idle>-0 [000] 521.442102: update_xtime_cache <-update_wall_time .... (It always print the time less than 2200 seconds besides ...) Because 'long' is 32bits in i386. ( (1<<31) useconds is about 2200 seconds) ... <idle>-0 [001] 4154502640.134759: rcu_bh_qsctr_inc <-__do_softirq <idle>-0 [001] 4154502640.134760: _local_bh_enable <-__do_softirq <idle>-0 [001] 4154502640.134761: idle_cpu <-irq_exit ... (very large value) Because 'long' is a signed type and it is 32bits in i386. Changes in v2: return 'unsigned long long' instead of 'cycle_t' Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <49D05D10.4030009@cn.fujitsu.com> Reported-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
*---. Merge branches 'tracing/docs', 'tracing/filters', 'tracing/ftrace', ↵Ingo Molnar2009-03-311-12/+38
|\ \ \ | | | | | | | | | | | | 'tracing/kprobes', 'tracing/blktrace-v2' and 'tracing/textedit' into tracing/core-v2
| | * | function-graph: add option for include sleep timesSteven Rostedt2009-03-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: give user a choice to show times spent while sleeping The user may want to see the time a function spent sleeping. This patch adds the trace option "sleep-time" to allow that. The "sleep-time" option is default on. echo sleep-time > /debug/tracing/trace_options produces: ------------------------------------------ 2) avahi-d-3428 => <idle>-0 ------------------------------------------ 2) | finish_task_switch() { 2) 0.621 us | _spin_unlock_irq(); 2) 2.202 us | } 2) ! 1002.197 us | } 2) ! 1003.521 us | } where as, echo nosleep-time > /debug/tracing/trace_options produces: 0) <idle>-0 => yum-upd-3416 ------------------------------------------ 0) | finish_task_switch() { 0) 0.643 us | _spin_unlock_irq(); 0) 2.342 us | } 0) + 41.302 us | } 0) + 42.453 us | } Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| | * | tracing/ftrace: check if debugfs is registered before creating filesFrederic Weisbecker2009-03-231-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix a crash with ftrace={nop,boot} parameter If the nop or initcall tracers are launched as boot tracers, they will attempt to create their option directory and files. But these tracers are registered very early and then assigned as "boot tracers" very early if asked to. Since they do this before debugfs has been registered (core initcall), a crash is triggered. Another early tracers could also come later. So we fix it by checking if debugfs is initialized before creating the root tracing directory. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237759847-21025-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: fix four sparse warningsDmitri Vorobiev2009-03-221-1/+1
| |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup. This patch fixes the following sparse warnings: kernel/trace/trace.c:385:9: warning: symbol 'trace_seq_to_buffer' was not declared. Should it be static? kernel/trace/trace_clock.c:29:13: warning: symbol 'trace_clock_local' was not declared. Should it be static? kernel/trace/trace_clock.c:54:13: warning: symbol 'trace_clock' was not declared. Should it be static? kernel/trace/trace_clock.c:74:13: warning: symbol 'trace_clock_global' was not declared. Should it be static? Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com> LKML-Reference: <1237741871-5827-4-git-send-email-dmitri.vorobiev@movial.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | tracing/function-graph-tracer: fix functions call traces imbalanceFrederic Weisbecker2009-03-231-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix traces output Sometimes one can observe an imbalance in the traces between function calls and function return traces: func1() { } } The curly brace inside func1() is the return of another function nested inside func1. The return trace have been inserted in the buffer but not the entry. We are storing a return address on the function traces stack while we haven't inserted its entry on the buffer, hence the imbalance on the traces. This is because the tracers doesn't check all failures that can happen on buffer insertion. This patch reports the tracing recursion failures and the ring buffer failures. In such cases, we now restore the original return address for the function, giving up its return trace. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237843021-11695-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | tracing/events: don't use wake up for eventsFrederic Weisbecker2009-03-231-5/+21
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix hard-lockup with sched switch events Some ftrace events, such as sched wakeup, can be traced while the runqueue lock is hold. Since they are using trace_current_buffer_unlock_commit(), they call wake_up() which can try to grab the runqueue lock too, resulting in a deadlock. Now for all event, we call a new helper: trace_nowake_buffer_unlock_commit() which do pretty the same than trace_current_buffer_unlock_commit() except than it doesn't call trace_wake_up(). Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237759847-21025-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | tracing/function-graph-tracer: prevent hangs during self-testsFrederic Weisbecker2009-03-221-3/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: detect tracing related hangs Sometimes, with some configs, the function graph tracer can make the timer interrupt too much slow, hanging the kernel in an endless loop of timer interrupts servicing. As suggested by Ingo, this patch brings a watchdog which stops the selftest after a defined number of functions traced, definitely disabling this tracer. For those who want to debug the cause of the function graph trace hang, you can pass the ftrace_dump_on_oops kernel parameter to dump the traces after this hang detection. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237694675-23509-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-201-47/+38
|\ \ | |/ |/| | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * tracing: remove recording function depth from trace_printkSteven Rostedt2009-03-191-5/+3
| | | | | | | | | | | | | | | | | | The function depth in trace_printk was to facilitate the function graph output. Now that the function graph calculates the depth within the trace output, we no longer need to record the depth when the trace_printk is called. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * tracing: make print_(b)printk_msg_only globalSteven Rostedt2009-03-191-34/+2
| | | | | | | | | | | | | | | | This patch makes print_printk_msg_only and print_bprintk_msg_only global for other functions to use. It also renames them by adding a "trace_" to the beginning to avoid namespace collisions. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * tracing: give easy way to clear trace bufferSteven Rostedt2009-03-181-8/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is currently no easy way to clear the trace buffer. Currently the only way is to change the current tracer. This patch lets the user clear the trace buffer by simply writing into the trace files. echo > /debug/tracing/trace or to clear a single cpu (i.e. for CPU 1): echo > /debug/tracing/per_cpu/cpu1/trace Requested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
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*---. \ Merge branches 'tracing/ftrace', 'tracing/kprobes', 'tracing/tasks' and ↵Ingo Molnar2009-03-201-14/+21
|\ \ \ \ | |_|_|/ |/| | | | | | | 'linus' into tracing/core
| | * | tracing: fix command line to pid reverse mapCarsten Emde2009-03-181-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix command line to pid mapping map_cmdline_to_pid[] is checked in trace_save_cmdline(), but never updated. This results in stale pid to command line mappings and the tracer output will associate the wrong comm string. Signed-off-by: Carsten Emde <Carsten.Emde@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: fix trace_find_cmdline()Thomas Gleixner2009-03-181-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: prevent stale command line output In case there is no valid command line mapping for a pid trace_find_cmdline() returns without updating the comm buffer. The trace dump keeps the previous entry which results in confusing trace output: <idle>-0 [000] 280.702056 .... <idle>-23456 [000] 280.702080 .... Update the comm buffer with "<...>" when no mapping is found. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: replace the crude (unsigned) -1 hackeryThomas Gleixner2009-03-181-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup The command line recorder uses (unsigned) -1 to mark non mapped entries in the pid to command line maps. The validity check is completely unintuitive: idx >= SAVED_CMDLINES There is no need for such casting games. Use a constant to mark unmapped entries and check for that constant to make the code readable and understandable. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | tracing: stop command line recording when tracing is disabledThomas Gleixner2009-03-181-1/+2
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: prevent overwrite of command line entries When the tracer is stopped the command line recording continues to record. The check for tracing_is_on() is not sufficient here as the ringbuffer status is not affected by setting debug/tracing/tracing_enabled to 0. On a non idle system this can result in the loss of the command line information for the stopped trace, which makes the trace harder to read and analyse. Check tracer_enabled to allow further recording. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-181-11/+44
|\ \ \ | |/ / |/| | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * | tracing: add global-clock option to provide cross CPU clock to tracesSteven Rostedt2009-03-171-4/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: feature to allow better serialized clock This patch adds an option called "global-clock" that will allow the tracer to switch to a slower but more accurate (across CPUs) clock. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | ring-buffer: add api to allow a tracer to change clock sourceSteven Rostedt2009-03-171-7/+14
| | | | | | | | | | | | | | | | | | | | | This patch adds a new function called ring_buffer_set_clock that allows a tracer to assign its own clock source to the buffer. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-171-9/+13
|\ \ \ | |/ / | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * | tracing: stop comm recording on tracing offSteven Rostedt2009-03-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix for losing comms in trace The command lines of tasks are cached at sched switch to not need to record them at every trace point. Disabling the tracing on stops the recording of traces, but does not stop the caching of command lines. When the tracing is off the cache may overflow and cause the tracing to show incorrect tasks matching the PIDs. This patch disables prevents updates to the comm cache when the ring buffer is off. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing: protect reader of cmdline outputSteven Rostedt2009-03-161-8/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix to one cause of incorrect comm outputs in trace The spinlock only protected the creation of a comm <=> pid pair. But it was possible that a reader could look up a pid, and get the wrong comm because it had no locking. This also required changing trace_find_cmdline to copy the comm cache and not just send back a pointer to it. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | tracing/core: fix early free of cpumasksFrederic Weisbecker2009-03-161-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix crashes when tracing cpumasks While ring-buffer allocation, the cpumasks are allocated too, including the tracing cpumask and the per-cpu file mask handler. But these cpumasks are freed accidentally just after. Fix it. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237164303-11476-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | tracing/core: fix missing mutex unlock on tracing_set_tracer()Frederic Weisbecker2009-03-161-1/+1
|/ / | | | | | | | | | | | | | | | | | | | | Impact: fix possible locking imbalance In case of ring buffer resize failure, tracing_set_tracer forgot to release trace_types_lock. Fix it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1237151439-6755-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | tracing: move binary buffers into per cpu directorySteven Rostedt2009-03-131-21/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The binary_buffers directory in /debugfs/tracing held the files to read the trace buffers in a binary format. This held one file per CPU buffer. But we also have a per_cpu directory that holds a way to read the pretty-print formats. This patch moves the binary buffers into the per_cpu_directory: # ls /debug/tracing/per_cpu/cpu1/ trace trace_pipe trace_pipe_raw The new name is called "trace_pipe_raw". The binary buffers always acted similar to trace_pipe, except that they produce raw data. Requested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | tracing/core: bring back raw trace_printk for dynamic formats stringsFrederic Weisbecker2009-03-121-5/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix callsites with dynamic format strings Since its new binary implementation, trace_printk() internally uses static containers for the format strings on each callsites. But the value is assigned once at build time, which means that it can't take dynamic formats. So this patch unearthes the raw trace_printk implementation for the callers that will need trace_printk to be able to carry these dynamic format strings. The trace_printk() macro will use the appropriate implementation for each callsite. Most of the time however, the binary implementation will still be used. The other impact of this patch is that mmiotrace_printk() will use the old implementation because it calls the low level trace_vprintk and we can't guess here whether the format passed in it is dynamic or not. Some parts of this patch have been written by Steven Rostedt (most notably the part that chooses the appropriate implementation for each callsites). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | tracing: show that buffer size is not expandedSteven Rostedt2009-03-121-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: do not confuse user on small trace buffer sizes When the system boots up, the trace buffer is small to conserve memory. It is only two pages per online CPU. When the tracer is used, it expands to the default value. This can confuse the user if they look at the buffer size and see only 7, but then later they see 1408. # cat /debug/tracing/buffer_size_kb 7 # echo sched_switch > /debug/tracing/current_tracer # cat /debug/tracing/buffer_size_kb 1408 This patch tries to help remove this confustion by showing that the buffer has not been expanded. # cat /debug/tracing/buffer_size_kb 7 (expanded: 1408) Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | tracing: protect ring_buffer_expanded with trace_types_lockSteven Rostedt2009-03-121-1/+4
| | | | | | | | | | | | | | | | | | | | | | Impact: prevent races with ring_buffer_expanded This patch places the expanding of the tracing buffer under the protection of the trace_types_lock mutex. It is highly unlikely that there would be any contention, but better safe than sorry. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | tracing: fix comments about trace buffer resizingSteven Rostedt2009-03-121-3/+16
| | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup Some of the comments about the trace buffer resizing is gobbledygook. And I wonder why people question if I'm a native English speaker. This patch makes the comments make a bit more sense. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | Merge branch 'tracing/ftrace' of ↵Steven Rostedt2009-03-121-10/+10
|\ \ | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip into trace/tip/tracing/ftrace-merge
| * \ Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-111-3/+7
| |\ \ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * \ \ Merge branch 'tip/tracing/ftrace' of ↵Ingo Molnar2009-03-101-1/+1
| |\ \ \ | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
| * | | | ftrace: tracing header should put '#' at the beginning of a lineKOSAKI Motohiro2009-03-081-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a recent discussion, Andrew Morton pointed out that tracing header should put '#' at the beginning of a line. Then, we can easily filtered the header by following grep usage: cat trace | grep -v '^#' Wakeup trace also has the same header problem. Comparison of headers displayed: before this patch: # tracer: wakeup # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip -------------------------------------------------------------------- latency: 19059 us, #21277/21277, CPU#1 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) ----------------- | task: kondemand/1-1644 (uid:0 nice:-5 policy:0 rt_prio:0) ----------------- # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / irqbalan-1887 1d.s. 0us : 1887:120:R + [001] 1644:115:S kondemand/1 irqbalan-1887 1d.s. 1us : default_wake_function <-autoremove_wake_function irqbalan-1887 1d.s. 2us : check_preempt_wakeup <-try_to_wake_up after this patch: # tracer: wakeup # # wakeup latency trace v1.1.5 on 2.6.29-rc7-tip-tip # -------------------------------------------------------------------- # latency: 529 us, #530/530, CPU#0 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: kondemand/0-1641 (uid:0 nice:-5 policy:0 rt_prio:0) # ----------------- # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / sshd-2496 0d.s. 0us : 2496:120:R + [000] 1641:115:S kondemand/0 sshd-2496 0d.s. 1us : default_wake_function <-autoremove_wake_function sshd-2496 0d.s. 1us : check_preempt_wakeup <-try_to_wake_up Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20090308124421.23C3.A69D9226@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | ring-buffer: only allocate buffers for online cpusSteven Rostedt2009-03-111-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: save on memory Currently, a ring buffer was allocated for each "possible_cpus". On some systems, this is the same as NR_CPUS. Thus, if a system defined NR_CPUS = 64 but it only had 1 CPU, we could have possibly 63 useless ring buffers taking up space. With a default buffer of 3 megs, this could be quite drastic. This patch changes the ring buffer code to only allocate ring buffers for online CPUs. If a CPU goes off line, we do not free the buffer. This is because the user may still have trace data in that buffer that they would like to look at. Perhaps in the future we could add code to delete a ring buffer if the CPU is offline and the ring buffer becomes empty. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | | | tracing: fix trace_wait to know to wait on all cpus or just oneSteven Rostedt2009-03-111-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix to task live locking on reading trace_pipe on one CPU The same code is used for both trace_pipe (all CPUS) and the per_cpu trace_pipe file. When there is no data to read, it will check for signals and wait on the trace wait queue. The problem happens with the per_cpu wait. The trace_wait code checks all CPUs. Thus, if there's data in another CPU buffer, then it will exit the wait, without checking for signals or waiting on the wait queue. It would then try to read the empty buffer, and since that will just return nothing, then it will try to wait again. Unfortunately, that will again fail due to there still being data in the other buffers. This ends up with a live lock for the task. This patch fixes the trace_wait to be aware that the iterator may only be waiting on a single buffer. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | | | tracing: expand the ring buffers when an event is activatedSteven Rostedt2009-03-111-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To save memory, the tracer ring buffers are set to a minimum. The activating of a trace expands the ring buffer size. This patch adds this expanding, when an event is activated. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | | | tracing: keep ring buffer to minimum size till usedSteven Rostedt2009-03-111-20/+59
| |_|/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: less memory impact on systems not using tracer When the kernel boots up that has tracing configured, it allocates the default size of the ring buffer. This currently happens to be 1.4Megs per possible CPU. This is quite a bit of wasted memory if the system is never using the tracer. The current solution is to keep the ring buffers to a minimum size until the user uses them. Once a tracer is piped into the current_tracer the ring buffer will be expanded to the default size. If the user changes the size of the ring buffer, it will take the size given by the user immediately. If the user adds a "ftrace=" to the kernel command line, then the ring buffers will be set to the default size on initialization. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | | tracing: use raw spinlocks for trace_vprintkSteven Rostedt2009-03-101-3/+7
| |/ / |/| | | | | | | | | | | | | | | | | | | | | | | Impact: prevent locking up by lockdep tracer The lockdep tracer uses trace_vprintk and thus trace_vprintk can not call back into lockdep without locking up. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | tracing: remove funky whitespace in the trace codeSteven Rostedt2009-03-101-1/+1
|/ / | | | | | | | | | | | | | | | | Impact: clean up There existed a lot of <space><tab>'s in the tracing code. This patch removes them. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | tracing/core: drop the old trace_printk() implementation in favour of ↵Frederic Weisbecker2009-03-061-150/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | trace_bprintk() Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | tracing: add trace_bprintk()Lai Jiangshan2009-03-061-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: add a generic printk() for tracing, like trace_printk() trace_bprintk() uses the infrastructure to record events on ring_buffer. [ fweisbec@gmail.com: ported to latest -tip, made it work if !CONFIG_MODULES, never free the format strings from modules because we can't keep track of them and conditionnaly create the ftrace format strings section (reported by Steven Rostedt) ] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | tracing: infrastructure for supporting binary recordLai Jiangshan2009-03-061-0/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: save on memory for tracing Current tracers are typically using a struct(like struct ftrace_entry, struct ctx_switch_entry, struct special_entr etc...)to record a binary event. These structs can only record a their own kind of events. A new kind of tracer need a new struct and a lot of code too handle it. So we need a generic binary record for events. This infrastructure is for this purpose. [fweisbec@gmail.com: rebase against latest -tip, make it safe while sched tracing as reported by Steven Rostedt] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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