github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-30 01:53:29 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

tracing: Record trace_clock and recover when reboot

Browse Source 
Record trace_clock information in the trace_scratch area and recover
the trace_clock when boot, so that reader can docode the timestamp
correctly.
Note that since most trace_clocks records the timestamp in nano-
seconds, this is not a bug. But some trace_clock, like counter and
tsc will record the counter value. Only for those trace_clock user
needs this information.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/174720625803.1925039.1815089037443798944.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu (Google) 2025-05-14 16:04:18 +09:00 committed by Steven Rostedt (Google)
parent 155fd6c3e2
commit 2632a2013f
1 changed files with 17 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
kernel/trace/trace.c
View File

@ -6066,6 +6066,7 @@ struct trace_mod_entry {
};
struct trace_scratch {
unsigned int clock_id;
unsigned long text_addr;
unsigned long nr_entries;
struct trace_mod_entry entries[];
@ -6181,6 +6182,7 @@ static void update_last_data(struct trace_array *tr)
if (tr->scratch) {
struct trace_scratch *tscratch = tr->scratch;
tscratch->clock_id = tr->clock_id;
memset(tscratch->entries, 0,
flex_array_size(tscratch, entries, tscratch->nr_entries));
tscratch->nr_entries = 0;
@ -7403,6 +7405,12 @@ int tracing_set_clock(struct trace_array *tr, const char *clockstr)
tracing_reset_online_cpus(&tr->max_buffer);
#endif
if (tr->scratch && !(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) {
struct trace_scratch *tscratch = tr->scratch;
tscratch->clock_id = i;
}
mutex_unlock(&trace_types_lock);
return 0;
@ -9628,6 +9636,15 @@ static void setup_trace_scratch(struct trace_array *tr,
/* Scan modules to make text delta for modules. */
module_for_each_mod(make_mod_delta, tr);
/* Set trace_clock as the same of the previous boot. */
if (tscratch->clock_id != tr->clock_id) {
if (tscratch->clock_id >= ARRAY_SIZE(trace_clocks) ||
tracing_set_clock(tr, trace_clocks[tscratch->clock_id].name) < 0) {
pr_info("the previous trace_clock info is not valid.");
goto reset;
}
}
return;
reset:
/* Invalid trace modules */