diff options
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 142 |
1 files changed, 124 insertions, 18 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 948ec32e0c27..2d0ffcc49dba 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1916,7 +1916,11 @@ static int trace_save_cmdline(struct task_struct *tsk) { unsigned pid, idx; - if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT)) + /* treat recording of idle task as a success */ + if (!tsk->pid) + return 1; + + if (unlikely(tsk->pid > PID_MAX_DEFAULT)) return 0; /* @@ -2002,7 +2006,11 @@ int trace_find_tgid(int pid) static int trace_save_tgid(struct task_struct *tsk) { - if (unlikely(!tgid_map || !tsk->pid || tsk->pid > PID_MAX_DEFAULT)) + /* treat recording of idle task as a success */ + if (!tsk->pid) + return 1; + + if (unlikely(!tgid_map || tsk->pid > PID_MAX_DEFAULT)) return 0; tgid_map[tsk->pid] = tsk->tgid; @@ -2029,11 +2037,20 @@ static bool tracing_record_taskinfo_skip(int flags) */ void tracing_record_taskinfo(struct task_struct *task, int flags) { + bool done; + if (tracing_record_taskinfo_skip(flags)) return; - if ((flags & TRACE_RECORD_CMDLINE) && !trace_save_cmdline(task)) - return; - if ((flags & TRACE_RECORD_TGID) && !trace_save_tgid(task)) + + /* + * Record as much task information as possible. If some fail, continue + * to try to record the others. + */ + done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task); + + /* If recording any information failed, retry again soon. */ + if (!done) return; __this_cpu_write(trace_taskinfo_save, false); @@ -2050,15 +2067,22 @@ void tracing_record_taskinfo(struct task_struct *task, int flags) void tracing_record_taskinfo_sched_switch(struct task_struct *prev, struct task_struct *next, int flags) { + bool done; + if (tracing_record_taskinfo_skip(flags)) return; - if ((flags & TRACE_RECORD_CMDLINE) && - (!trace_save_cmdline(prev) || !trace_save_cmdline(next))) - return; + /* + * Record as much task information as possible. If some fail, continue + * to try to record the others. + */ + done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev); + done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next); - if ((flags & TRACE_RECORD_TGID) && - (!trace_save_tgid(prev) || !trace_save_tgid(next))) + /* If recording any information failed, retry again soon. */ + if (!done) return; __this_cpu_write(trace_taskinfo_save, false); @@ -3334,14 +3358,23 @@ static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file unsigned int flags) { bool tgid = flags & TRACE_ITER_RECORD_TGID; - - seq_printf(m, "# %s _-----=> irqs-off\n", tgid ? " " : ""); - seq_printf(m, "# %s / _----=> need-resched\n", tgid ? " " : ""); - seq_printf(m, "# %s| / _---=> hardirq/softirq\n", tgid ? " " : ""); - seq_printf(m, "# %s|| / _--=> preempt-depth\n", tgid ? " " : ""); - seq_printf(m, "# %s||| / delay\n", tgid ? " " : ""); - seq_printf(m, "# TASK-PID CPU#%s|||| TIMESTAMP FUNCTION\n", tgid ? " TGID " : ""); - seq_printf(m, "# | | | %s|||| | |\n", tgid ? " | " : ""); + const char tgid_space[] = " "; + const char space[] = " "; + + seq_printf(m, "# %s _-----=> irqs-off\n", + tgid ? tgid_space : space); + seq_printf(m, "# %s / _----=> need-resched\n", + tgid ? tgid_space : space); + seq_printf(m, "# %s| / _---=> hardirq/softirq\n", + tgid ? tgid_space : space); + seq_printf(m, "# %s|| / _--=> preempt-depth\n", + tgid ? tgid_space : space); + seq_printf(m, "# %s||| / delay\n", + tgid ? tgid_space : space); + seq_printf(m, "# TASK-PID CPU#%s|||| TIMESTAMP FUNCTION\n", + tgid ? " TGID " : space); + seq_printf(m, "# | | | %s|||| | |\n", + tgid ? " | " : space); } void @@ -4689,6 +4722,76 @@ static const struct file_operations tracing_readme_fops = { .llseek = generic_file_llseek, }; +static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos) +{ + int *ptr = v; + + if (*pos || m->count) + ptr++; + + (*pos)++; + + for (; ptr <= &tgid_map[PID_MAX_DEFAULT]; ptr++) { + if (trace_find_tgid(*ptr)) + return ptr; + } + + return NULL; +} + +static void *saved_tgids_start(struct seq_file *m, loff_t *pos) +{ + void *v; + loff_t l = 0; + + if (!tgid_map) + return NULL; + + v = &tgid_map[0]; + while (l <= *pos) { + v = saved_tgids_next(m, v, &l); + if (!v) + return NULL; + } + + return v; +} + +static void saved_tgids_stop(struct seq_file *m, void *v) +{ +} + +static int saved_tgids_show(struct seq_file *m, void *v) +{ + int pid = (int *)v - tgid_map; + + seq_printf(m, "%d %d\n", pid, trace_find_tgid(pid)); + return 0; +} + +static const struct seq_operations tracing_saved_tgids_seq_ops = { + .start = saved_tgids_start, + .stop = saved_tgids_stop, + .next = saved_tgids_next, + .show = saved_tgids_show, +}; + +static int tracing_saved_tgids_open(struct inode *inode, struct file *filp) +{ + if (tracing_disabled) + return -ENODEV; + + return seq_open(filp, &tracing_saved_tgids_seq_ops); +} + + +static const struct file_operations tracing_saved_tgids_fops = { + .open = tracing_saved_tgids_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos) { unsigned int *ptr = v; @@ -7921,6 +8024,9 @@ static __init int tracer_init_tracefs(void) trace_create_file("saved_cmdlines_size", 0644, d_tracer, NULL, &tracing_saved_cmdlines_size_fops); + trace_create_file("saved_tgids", 0444, d_tracer, + NULL, &tracing_saved_tgids_fops); + trace_eval_init(); trace_create_eval_file(d_tracer); |