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2014-11-19tracing: Add trace_seq_has_overflowed() and trace_handle_return()Steven Rostedt (Red Hat)
Adding a trace_seq_has_overflowed() which returns true if the trace_seq had too much written into it allows us to simplify the code. Instead of checking the return value of every call to trace_seq_printf() and friends, they can all be called normally, and at the end we can return !trace_seq_has_overflowed() instead. Several functions also return TRACE_TYPE_PARTIAL_LINE when the trace_seq overflowed and TRACE_TYPE_HANDLED otherwise. Another helper function was created called trace_handle_return() which takes a trace_seq and returns these enums. Using this helper function also simplifies the code. This change also makes it possible to remove the return values of trace_seq_printf() and friends. They should instead just be void functions. Link: http://lkml.kernel.org/r/20141114011410.365183157@goodmis.org Reviewed-by: Petr Mladek <pmladek@suse.cz> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01tracing: Make trace_seq_putmem_hex() more robustSteven Rostedt (Red Hat)
Currently trace_seq_putmem_hex() can only take as a parameter a pointer to something that is 8 bytes or less, otherwise it will overflow the buffer. This is protected by a macro that encompasses the call to trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before it is passed in. This is not very robust and if trace_seq_putmem_hex() ever gets used outside that macro it will cause issues. Instead of only being able to produce a hex output of memory that is for a single word, change it to be more robust and allow any size input. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-07-01tracing: Move the trace_seq_* functions into its own trace_seq.c fileSteven Rostedt (Red Hat)
The trace_seq_*() functions are a nice utility that allows users to manipulate buffers with printf() like formats. It has its own trace_seq.h header in include/linux and should be in its own file. Being tied with trace_output.c is rather awkward. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15tracing: Rename trace_event_mutex to trace_event_semzhangwei(Jovi)
trace_event_mutex is an rw semaphore now, not a mutex, change the name. Link: http://lkml.kernel.org/r/513D843B.40109@huawei.com Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> [ Forward ported to my new code ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15tracing: Add trace_puts() for even faster trace_printk() tracingSteven Rostedt (Red Hat)
The trace_printk() is extremely fast and is very handy as it can be used in any context (including NMIs!). But it still requires scanning the fmt string for parsing the args. Even the trace_bprintk() requires a scan to know what args will be saved, although it doesn't copy the format string itself. Several times trace_printk() has no args, and wastes cpu cycles scanning the fmt string. Adding trace_puts() allows the developer to use an even faster tracing method that only saves the pointer to the string in the ring buffer without doing any format parsing at all. This will help remove even more of the "Heisenbug" effect, when debugging. Also fixed up the F_printk()s for the ftrace internal bprint and print events. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-05-14tracing: Allow events to share their print functionsSteven Rostedt
Multiple events may use the same method to print their data. Instead of having all events have a pointer to their print funtions, the trace_event structure now points to a trace_event_functions structure that will hold the way to print ouf the event. The event itself is now passed to the print function to let the print function know what kind of event it should print. This opens the door to consolidating the way several events print their output. text data bss dec hex filename 4913961 1088356 861512 6863829 68bbd5 vmlinux.orig 4900382 1048964 861512 6810858 67ecea vmlinux.init 4900446 1049028 861512 6810986 67ed6a vmlinux.preprint This change slightly increases the size but is needed for the next change. v3: Fix the branch tracer events to handle this change. v2: Fix the new function graph tracer event calls to handle this change. Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-11tracing: consolidate code between trace_output.c and trace_function_graph.cSteven Rostedt
Both trace_output.c and trace_function_graph.c do basically the same thing to handle the printing of the latency-format. This patch moves the code into one function that both can use. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-09tracing: add protection around module events unloadSteven Rostedt
When reading the trace buffer, there is a race that when a module is unloaded it removes events that is stilled referenced in the buffers. This patch adds the protection around the unloading of the events from modules and the reading of the trace buffers. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-25tracing: add trace_event_read_lock()Lai Jiangshan
I found that there is nothing to protect event_hash in ftrace_find_event(). Rcu protects the event hashlist but not the event itself while we use it after its extraction through ftrace_find_event(). This lack of a proper locking in this spot opens a race window between any event dereferencing and module removal. Eg: --Task A-- print_trace_line(trace) { event = find_ftrace_event(trace) --Task B-- trace_module_remove_events(mod) { list_trace_events_module(ev, mod) { unregister_ftrace_event(ev->event) { hlist_del(ev->event->node) list_del(....) } } } |--> module removed, the event has been dropped --Task A-- event->print(trace); // Dereferencing freed memory If the event retrieved belongs to a module and this module is concurrently removed, we may end up dereferencing a data from a freed module. RCU could solve this, but it would add latency to the kernel and forbid tracers output callbacks to call any sleepable code. So this fix converts 'trace_event_mutex' to a read/write semaphore, and adds trace_event_read_lock() to protect ftrace_find_event(). [ Impact: fix possible freed memory dereference in ftrace ] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A114806.7090302@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-04-14tracing/events: move declarations from trace directory to core includeSteven Rostedt
In preparation to allowing trace events to happen in modules, we need to move some of the local declarations in the kernel/trace directory into include/linux. This patch simply moves the declarations and performs no context changes. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-14tracing: make trace_seq operations available for core kernelSteven Rostedt
In the process to make TRACE_EVENT macro work for modules, the trace_seq operations must be available for core kernel code. These operations are quite useful and can be used for other implementations. The main idea is that we create a trace_seq handle that acts very much like the seq_file handle. struct trace_seq *s = kmalloc(sizeof(*s, GFP_KERNEL); trace_seq_init(s); trace_seq_printf(s, "some data %d\n", variable); printk("%s", s->buffer); The main use is to allow a top level function call several other functions that may store printf like data into the buffer. Then at the end, the top level function can process all the data with any method it would like to. It could be passed to userspace, output via printk or even use seq_file: trace_seq_to_user(s, ubuf, cnt); seq_puts(m, s->buffer); Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-07Merge branch 'linus' into tracing/coreIngo Molnar
Merge reason: update to upstream tracing facilities Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31trace: make argument 'mem' of trace_seq_putmem() constLi Zefan
Impact: fix build warning I passed a const value to trace_seq_putmem(), and I got compile warning. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31tracing: add missing 'extern' keywords to trace_output.hEduard - Gabriel Munteanu
Impact: cleanup Many declarations within trace_output.h are missing the 'extern' keyword in an inconsistent manner. This adds 'extern' where it should be. Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31tracing: provide trace_seq_reserve()Eduard - Gabriel Munteanu
trace_seq_reserve() allows a caller to reserve space in a trace_seq and write directly into it. This makes it easier to export binary data to userspace via the tracing interface, by simply filling in a struct. Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-24tracing: adding function timings to function profilerSteven Rostedt
If the function graph trace is enabled, the function profiler will use it to take the timing of the functions. cat /debug/tracing/trace_stat/functions Function Hit Time -------- --- ---- mwait_idle 127 183028.4 us schedule 26 151997.7 us __schedule 31 151975.1 us sys_wait4 2 74080.53 us do_wait 2 74077.80 us sys_newlstat 138 39929.16 us do_path_lookup 179 39845.79 us vfs_lstat_fd 138 39761.97 us user_path_at 153 39469.58 us path_walk 179 39435.76 us __link_path_walk 189 39143.73 us [...] Note the times are skewed due to the function graph tracer not taking into account schedules. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-03-19tracing: make print_(b)printk_msg_only globalSteven Rostedt
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>
2009-03-06tracing/core: drop the old trace_printk() implementation in favour of ↵Frederic Weisbecker
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>
2009-03-04tracing: remove extra latency_trace method from trace structureSteven Rostedt
Impact: clean up The trace and latency_trace function pointers are identical for every tracer but the function tracer. The differences in the function tracer are trivial (latency output puts paranthesis around parent). This patch removes the latency_trace pointer and all prints will now just use the trace output function pointer. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-04trace: make the trace_event callbacks return enum print_line_tArnaldo Carvalho de Melo
As they actually all return these enumerators. Reported-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03trace: Change struct trace_event callbacks parameter listArnaldo Carvalho de Melo
Impact: API change The trace_seq and trace_entry are in trace_iterator, where there are more fields that may be needed by tracers, so just pass the tracer_iterator as is already the case for struct tracer->print_line. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03trace: better manage the context info for eventsFrederic Weisbecker
Impact: make trace_event more convenient for tracers All tracers (for the moment) that use the struct trace_event want to have the context info printed before their own output: the pid/cmdline, cpu, and timestamp. But some other tracers that want to implement their trace_event callbacks will not necessary need these information or they may want to format them as they want. This patch adds a new default-enabled trace option: TRACE_ITER_CONTEXT_INFO When disabled through: echo nocontext-info > /debugfs/tracing/trace_options The pid, cpu and timestamps headers will not be printed. IE with the sched_switch tracer with context-info (default): bash-2935 [001] 100.356561: 2935:120:S ==> [001] 0:140:R <idle> <idle>-0 [000] 100.412804: 0:140:R + [000] 11:115:S events/0 <idle>-0 [000] 100.412816: 0:140:R ==> [000] 11:115:R events/0 events/0-11 [000] 100.412829: 11:115:S ==> [000] 0:140:R <idle> Without context-info: 2935:120:S ==> [001] 0:140:R <idle> 0:140:R + [000] 11:115:S events/0 0:140:R ==> [000] 11:115:R events/0 11:115:S ==> [000] 0:140:R <idle> A tracer can disable it at runtime by clearing the bit TRACE_ITER_CONTEXT_INFO in trace_flags. The print routines were renamed to trace_print_context and trace_print_lat_context, so that they can be used by tracers if they want to use them for one of the trace_event callbacks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-16trace: add gcc printf check to trace_seq_printfSteven Rostedt
Andrew Morton suggested adding a printf checker to trace_seq_printf since there are a number of users that have improper format arguments. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-16ftrace: fix trace_outputLai Jiangshan
Impact: fix bug for handling partial line trace_seq_printf(), seq_print_userip_objs(), ... return 0 -- partial line was written other(>0) -- success duplicate output is also removed in trace_print_raw(). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-29ftrace: change trace.c to use registered eventsSteven Rostedt
Impact: rework trace.c to use new event register API Almost every ftrace event has to implement its output display in trace.c through a different function. Some events did not handle all the formats (trace, latency-trace, raw, hex, binary), and this method does not scale well. This patch converts the format functions to use the event API to find the event and and print its format. Currently, we have a print function for trace, latency_trace, raw, hex and binary. A trace_nop_print is available if the event wants to avoid output on a particular format. Perhaps other tracers could use this in the future (like mmiotrace and function_graph). Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-29ftrace: set up trace event hash infrastructureSteven Rostedt
Impact: simplify/generalize/refactor trace.c The trace.c file is becoming more difficult to maintain due to the growing number of events. There is several formats that an event may be printed. This patch sets up the infrastructure of an event hash to allow for events to register how they should be printed. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>