Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-26 14:12:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

tracing: Add saved_tgids file to show cached pid to tgid mappings

Browse Source 
Export the cached pid / tgid mappings in debugfs tracing saved_tgids file.
This allows user apps to translate the pids from a trace to their respective
thread group.

Example saved_tgids file with pid / tgid values separated by ' ':

  # cat saved_tgids
  1048 1048
  1047 1047
  7 7
  1049 1047
  1054 1047
  1053 1047

Link: http://lkml.kernel.org/r/20170630004023.064965233@goodmis.org
Link: http://lkml.kernel.org/r/20170706040713.unwkumbta5menygi@mikesart-cos

Reviewed-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Michael Sartain <mikesart@fastmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Michael Sartain 2017-07-05 22:07:15 -06:00 committed by Steven Rostedt (VMware)
parent 69d71879d2
commit 99c621d704
1 changed files with 73 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
kernel/trace/trace.c
View File

@ -4688,6 +4688,76 @@ 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;
@ -7920,6 +7990,9 @@ 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);