Messages in this thread | | | From | Mark-PK Tsai <> | Subject | [PATCH v4 0/2] tracing: make tracer_init_tracefs initcall asynchronous | Date | Tue, 26 Apr 2022 20:24:05 +0800 |
| |
Move trace_eval_init() to subsys_initcall to make it start earlier. And to avoid tracer_init_tracefs being blocked by trace_event_sem which trace_eval_init() hold [1], queue tracer_init_tracefs() to eval_map_wq to let the two works being executed sequentially.
It can speed up the initialization of kernel as result of making tracer_init_tracefs asynchronous.
On my arm64 platform, it reduce ~20ms of 125ms which total time do_initcalls spend.
Changes in v2: - Fix the use of ftrace_eval_maps in INIT_DATA after initmem_free().
In v1, a kthread is create for tracer_init_tracefs() which might cause kernel crash if initmem is free before it finish. In v2, the work of tracer_init_tracefs() is separated into 2 parts, one is put to subsys_initcall and the other is queue to eval_map_wq which can make sure it always finish before initmem is free.
Changes in v3: - Avoid adding tracer option before __update_tracer_options finish to fix the warning report by kernel test robot.
Reported-by: kernel test robot <oliver.sang@intel.com> https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/
Changes in v4: - Set `tracer_options_updated = true` before calling __update_tracer_options(). Otherwise, __update_tracer_options() will skip all the tracer in trace_array. - Init tracerfs_init_work only when eval_map_wq is successfully created.
Mark-PK Tsai (2): tracing: Avoid adding tracer option before update_tracer_options tracing: make tracer_init_tracefs initcall asynchronous
kernel/trace/trace.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-)
-- 2.18.0
| |