tracing: Add support for recording tgid of tasks
Inorder to support recording of tgid, the following changes are made: * Introduce a new API (tracing_record_taskinfo) to additionally record the tgid along with the task's comm at the same time. This has has the benefit of not setting trace_cmdline_save before all the information for a task is saved. * Add a new API tracing_record_taskinfo_sched_switch to record task information for 2 tasks at a time (previous and next) and use it from sched_switch probe. * Preserve the old API (tracing_record_cmdline) and create it as a wrapper around the new one so that existing callers aren't affected. * Reuse the existing sched_switch and sched_wakeup probes to record tgid information and add a new option 'record-tgid' to enable recording of tgid When record-tgid option isn't enabled to being with, we take care to make sure that there's isn't memory or runtime overhead. Link: http://lkml.kernel.org/r/20170627020155.5139-1-joelaf@google.com Cc: kernel-team@android.com Cc: Ingo Molnar <mingo@redhat.com> Tested-by: Michael Sartain <mikesart@gmail.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Joel Fernandes
Steven Rostedt (VMware)
parent
83dd14933e
commit
d914ba37d7
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@ -151,7 +151,15 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
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int type, unsigned long len,
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unsigned long flags, int pc);
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void tracing_record_cmdline(struct task_struct *tsk);
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#define TRACE_RECORD_CMDLINE BIT(0)
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#define TRACE_RECORD_TGID BIT(1)
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void tracing_record_taskinfo(struct task_struct *task, int flags);
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void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
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struct task_struct *next, int flags);
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void tracing_record_cmdline(struct task_struct *task);
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void tracing_record_tgid(struct task_struct *task);
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int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...);
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@ -290,6 +298,7 @@ struct trace_subsystem_dir;
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enum {
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EVENT_FILE_FL_ENABLED_BIT,
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EVENT_FILE_FL_RECORDED_CMD_BIT,
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EVENT_FILE_FL_RECORDED_TGID_BIT,
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EVENT_FILE_FL_FILTERED_BIT,
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EVENT_FILE_FL_NO_SET_FILTER_BIT,
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EVENT_FILE_FL_SOFT_MODE_BIT,
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@ -303,6 +312,7 @@ enum {
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* Event file flags:
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* ENABLED - The event is enabled
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* RECORDED_CMD - The comms should be recorded at sched_switch
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* RECORDED_TGID - The tgids should be recorded at sched_switch
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* FILTERED - The event has a filter attached
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* NO_SET_FILTER - Set when filter has error and is to be ignored
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* SOFT_MODE - The event is enabled/disabled by SOFT_DISABLED
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@ -315,6 +325,7 @@ enum {
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enum {
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EVENT_FILE_FL_ENABLED = (1 << EVENT_FILE_FL_ENABLED_BIT),
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EVENT_FILE_FL_RECORDED_CMD = (1 << EVENT_FILE_FL_RECORDED_CMD_BIT),
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EVENT_FILE_FL_RECORDED_TGID = (1 << EVENT_FILE_FL_RECORDED_TGID_BIT),
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EVENT_FILE_FL_FILTERED = (1 << EVENT_FILE_FL_FILTERED_BIT),
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EVENT_FILE_FL_NO_SET_FILTER = (1 << EVENT_FILE_FL_NO_SET_FILTER_BIT),
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EVENT_FILE_FL_SOFT_MODE = (1 << EVENT_FILE_FL_SOFT_MODE_BIT),
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@ -87,7 +87,7 @@ dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
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* tracing is active, only save the comm when a trace event
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* occurred.
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*/
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static DEFINE_PER_CPU(bool, trace_cmdline_save);
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static DEFINE_PER_CPU(bool, trace_taskinfo_save);
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/*
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* Kill all tracing for good (never come back).
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@ -790,7 +790,7 @@ EXPORT_SYMBOL_GPL(tracing_on);
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static __always_inline void
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__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
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{
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__this_cpu_write(trace_cmdline_save, true);
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__this_cpu_write(trace_taskinfo_save, true);
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/* If this is the temp buffer, we need to commit fully */
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if (this_cpu_read(trace_buffered_event) == event) {
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@ -1709,6 +1709,8 @@ void tracing_reset_all_online_cpus(void)
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}
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}
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static int *tgid_map;
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#define SAVED_CMDLINES_DEFAULT 128
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#define NO_CMDLINE_MAP UINT_MAX
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static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
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@ -1722,7 +1724,7 @@ struct saved_cmdlines_buffer {
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static struct saved_cmdlines_buffer *savedcmd;
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/* temporary disable recording */
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static atomic_t trace_record_cmdline_disabled __read_mostly;
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static atomic_t trace_record_taskinfo_disabled __read_mostly;
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static inline char *get_saved_cmdlines(int idx)
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{
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@ -1990,16 +1992,87 @@ void trace_find_cmdline(int pid, char comm[])
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preempt_enable();
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}
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void tracing_record_cmdline(struct task_struct *tsk)
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int trace_find_tgid(int pid)
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{
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if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
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if (unlikely(!tgid_map || !pid || pid > PID_MAX_DEFAULT))
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return 0;
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return tgid_map[pid];
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}
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static int trace_save_tgid(struct task_struct *tsk)
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{
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if (unlikely(!tgid_map || !tsk->pid || tsk->pid > PID_MAX_DEFAULT))
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return 0;
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tgid_map[tsk->pid] = tsk->tgid;
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return 1;
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}
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static bool tracing_record_taskinfo_skip(int flags)
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{
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if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
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return true;
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if (atomic_read(&trace_record_taskinfo_disabled) || !tracing_is_on())
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return true;
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if (!__this_cpu_read(trace_taskinfo_save))
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return true;
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return false;
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}
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/**
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* tracing_record_taskinfo - record the task info of a task
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*
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* @task - task to record
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* @flags - TRACE_RECORD_CMDLINE for recording comm
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* - TRACE_RECORD_TGID for recording tgid
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*/
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void tracing_record_taskinfo(struct task_struct *task, int flags)
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{
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if (tracing_record_taskinfo_skip(flags))
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return;
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if ((flags & TRACE_RECORD_CMDLINE) && !trace_save_cmdline(task))
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return;
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if ((flags & TRACE_RECORD_TGID) && !trace_save_tgid(task))
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return;
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if (!__this_cpu_read(trace_cmdline_save))
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__this_cpu_write(trace_taskinfo_save, false);
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}
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/**
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* tracing_record_taskinfo_sched_switch - record task info for sched_switch
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*
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* @prev - previous task during sched_switch
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* @next - next task during sched_switch
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* @flags - TRACE_RECORD_CMDLINE for recording comm
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* TRACE_RECORD_TGID for recording tgid
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*/
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void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
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struct task_struct *next, int flags)
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{
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if (tracing_record_taskinfo_skip(flags))
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return;
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if (trace_save_cmdline(tsk))
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__this_cpu_write(trace_cmdline_save, false);
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if ((flags & TRACE_RECORD_CMDLINE) &&
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(!trace_save_cmdline(prev) || !trace_save_cmdline(next)))
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return;
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if ((flags & TRACE_RECORD_TGID) &&
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(!trace_save_tgid(prev) || !trace_save_tgid(next)))
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return;
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__this_cpu_write(trace_taskinfo_save, false);
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}
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/* Helpers to record a specific task information */
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void tracing_record_cmdline(struct task_struct *task)
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{
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tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
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}
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void tracing_record_tgid(struct task_struct *task)
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{
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tracing_record_taskinfo(task, TRACE_RECORD_TGID);
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}
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/*
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@ -3144,7 +3217,7 @@ static void *s_start(struct seq_file *m, loff_t *pos)
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#endif
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if (!iter->snapshot)
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atomic_inc(&trace_record_cmdline_disabled);
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atomic_inc(&trace_record_taskinfo_disabled);
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if (*pos != iter->pos) {
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iter->ent = NULL;
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@ -3189,7 +3262,7 @@ static void s_stop(struct seq_file *m, void *p)
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#endif
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if (!iter->snapshot)
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atomic_dec(&trace_record_cmdline_disabled);
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atomic_dec(&trace_record_taskinfo_disabled);
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trace_access_unlock(iter->cpu_file);
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trace_event_read_unlock();
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@ -4236,6 +4309,18 @@ int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
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if (mask == TRACE_ITER_RECORD_CMD)
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trace_event_enable_cmd_record(enabled);
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if (mask == TRACE_ITER_RECORD_TGID) {
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if (!tgid_map)
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tgid_map = kzalloc((PID_MAX_DEFAULT + 1) * sizeof(*tgid_map),
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GFP_KERNEL);
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if (!tgid_map) {
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tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
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return -ENOMEM;
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}
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trace_event_enable_tgid_record(enabled);
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}
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if (mask == TRACE_ITER_EVENT_FORK)
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trace_event_follow_fork(tr, enabled);
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@ -640,6 +640,9 @@ void set_graph_array(struct trace_array *tr);
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void tracing_start_cmdline_record(void);
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void tracing_stop_cmdline_record(void);
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void tracing_start_tgid_record(void);
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void tracing_stop_tgid_record(void);
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int register_tracer(struct tracer *type);
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int is_tracing_stopped(void);
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@ -700,6 +703,7 @@ static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
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extern u64 ftrace_now(int cpu);
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extern void trace_find_cmdline(int pid, char comm[]);
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extern int trace_find_tgid(int pid);
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extern void trace_event_follow_fork(struct trace_array *tr, bool enable);
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#ifdef CONFIG_DYNAMIC_FTRACE
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@ -1124,6 +1128,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
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C(CONTEXT_INFO, "context-info"), /* Print pid/cpu/time */ \
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C(LATENCY_FMT, "latency-format"), \
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C(RECORD_CMD, "record-cmd"), \
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C(RECORD_TGID, "record-tgid"), \
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C(OVERWRITE, "overwrite"), \
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C(STOP_ON_FREE, "disable_on_free"), \
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C(IRQ_INFO, "irq-info"), \
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@ -1440,6 +1445,8 @@ struct ftrace_event_field *
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trace_find_event_field(struct trace_event_call *call, char *name);
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extern void trace_event_enable_cmd_record(bool enable);
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extern void trace_event_enable_tgid_record(bool enable);
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extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
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extern int event_trace_del_tracer(struct trace_array *tr);
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@ -343,6 +343,28 @@ void trace_event_enable_cmd_record(bool enable)
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mutex_unlock(&event_mutex);
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}
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void trace_event_enable_tgid_record(bool enable)
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{
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struct trace_event_file *file;
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struct trace_array *tr;
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mutex_lock(&event_mutex);
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do_for_each_event_file(tr, file) {
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if (!(file->flags & EVENT_FILE_FL_ENABLED))
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continue;
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if (enable) {
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tracing_start_tgid_record();
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set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
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} else {
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tracing_stop_tgid_record();
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clear_bit(EVENT_FILE_FL_RECORDED_TGID_BIT,
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&file->flags);
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}
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} while_for_each_event_file();
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mutex_unlock(&event_mutex);
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}
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static int __ftrace_event_enable_disable(struct trace_event_file *file,
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int enable, int soft_disable)
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{
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@ -381,6 +403,12 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
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tracing_stop_cmdline_record();
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clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
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}
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if (file->flags & EVENT_FILE_FL_RECORDED_TGID) {
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tracing_stop_tgid_record();
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clear_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
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}
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call->class->reg(call, TRACE_REG_UNREGISTER, file);
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}
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/* If in SOFT_MODE, just set the SOFT_DISABLE_BIT, else clear it */
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@ -407,18 +435,30 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
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}
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if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
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bool cmd = false, tgid = false;
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/* Keep the event disabled, when going to SOFT_MODE. */
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if (soft_disable)
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set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags);
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if (tr->trace_flags & TRACE_ITER_RECORD_CMD) {
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cmd = true;
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tracing_start_cmdline_record();
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set_bit(EVENT_FILE_FL_RECORDED_CMD_BIT, &file->flags);
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}
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if (tr->trace_flags & TRACE_ITER_RECORD_TGID) {
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tgid = true;
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tracing_start_tgid_record();
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set_bit(EVENT_FILE_FL_RECORDED_TGID_BIT, &file->flags);
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}
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ret = call->class->reg(call, TRACE_REG_REGISTER, file);
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if (ret) {
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if (cmd)
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tracing_stop_cmdline_record();
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if (tgid)
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tracing_stop_tgid_record();
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pr_info("event trace: Could not enable event "
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"%s\n", trace_event_name(call));
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break;
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@ -12,27 +12,38 @@
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#include "trace.h"
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static int sched_ref;
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#define RECORD_CMDLINE 1
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#define RECORD_TGID 2
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static int sched_cmdline_ref;
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static int sched_tgid_ref;
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static DEFINE_MUTEX(sched_register_mutex);
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static void
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probe_sched_switch(void *ignore, bool preempt,
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struct task_struct *prev, struct task_struct *next)
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{
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if (unlikely(!sched_ref))
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return;
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int flags;
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tracing_record_cmdline(prev);
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tracing_record_cmdline(next);
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flags = (RECORD_TGID * !!sched_tgid_ref) +
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(RECORD_CMDLINE * !!sched_cmdline_ref);
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if (!flags)
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return;
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tracing_record_taskinfo_sched_switch(prev, next, flags);
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}
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static void
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probe_sched_wakeup(void *ignore, struct task_struct *wakee)
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{
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if (unlikely(!sched_ref))
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return;
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int flags;
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tracing_record_cmdline(current);
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flags = (RECORD_TGID * !!sched_tgid_ref) +
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(RECORD_CMDLINE * !!sched_cmdline_ref);
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if (!flags)
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return;
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tracing_record_taskinfo(current, flags);
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}
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static int tracing_sched_register(void)
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@ -75,28 +86,61 @@ static void tracing_sched_unregister(void)
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unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
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}
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static void tracing_start_sched_switch(void)
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static void tracing_start_sched_switch(int ops)
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{
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bool sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
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mutex_lock(&sched_register_mutex);
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if (!(sched_ref++))
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switch (ops) {
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case RECORD_CMDLINE:
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sched_cmdline_ref++;
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break;
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case RECORD_TGID:
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sched_tgid_ref++;
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break;
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}
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if (sched_register && (sched_cmdline_ref || sched_tgid_ref))
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tracing_sched_register();
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mutex_unlock(&sched_register_mutex);
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}
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static void tracing_stop_sched_switch(void)
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static void tracing_stop_sched_switch(int ops)
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{
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mutex_lock(&sched_register_mutex);
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if (!(--sched_ref))
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switch (ops) {
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case RECORD_CMDLINE:
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sched_cmdline_ref--;
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break;
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case RECORD_TGID:
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sched_tgid_ref--;
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break;
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}
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if (!sched_cmdline_ref && !sched_tgid_ref)
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tracing_sched_unregister();
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mutex_unlock(&sched_register_mutex);
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}
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void tracing_start_cmdline_record(void)
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{
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tracing_start_sched_switch();
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tracing_start_sched_switch(RECORD_CMDLINE);
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}
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void tracing_stop_cmdline_record(void)
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{
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tracing_stop_sched_switch();
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tracing_stop_sched_switch(RECORD_CMDLINE);
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}
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void tracing_start_tgid_record(void)
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{
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tracing_start_sched_switch(RECORD_TGID);
|
||||
}
|
||||
|
||||
void tracing_stop_tgid_record(void)
|
||||
{
|
||||
tracing_stop_sched_switch(RECORD_TGID);
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user