Hi, Here is the v6 of the series to improve backup instances of the persistent ring buffer. The previous version is here:
https://lore.kernel.org/all/176955897718.2786091.11948759407196200082.st...@mhiramat.tok.corp.google.com/ This version cleanup code and fix typo, according to Steve's comments. Also fix to init autoremove_wq only when the readonly instance has been made. A major UI change is that the tracing_on file is also removed from readonly instance. Since backup instances are a kind of snapshot of the persistent ring buffer, it should be readonly. And if it is readonly there is no reason to keep it after reading all data via trace_pipe because the data has been consumed. But user should be able to remove the readonly instance by rmdir or truncating `trace` file. Thus, [2/4] makes backup instances readonly (not able to write any events, cleanup trace, change buffer size). Also, [3/4] removes the backup instance after consuming all data via trace_pipe. With this improvements, even if we makes a backup instance (using the same amount of memory of the persistent ring buffer), it will be removed after reading the data automatically. --- Masami Hiramatsu (Google) (4): tracing: Reset last_boot_info if ring buffer is reset tracing: Make the backup instance non-reusable tracing: Remove the backup instance automatically after read tracing/Documentation: Add a section about backup instance Documentation/trace/debugging.rst | 19 ++++ kernel/trace/trace.c | 162 ++++++++++++++++++++++++++++++------- kernel/trace/trace.h | 13 +++ kernel/trace/trace_boot.c | 5 + kernel/trace/trace_events.c | 76 ++++++++++------- 5 files changed, 209 insertions(+), 66 deletions(-) -- Masami Hiramatsu (Google) <[email protected]>
