kernel/latencytop.c: remove unnecessary checks for latencytop_enabled
1. In latencytop source codes, we only have such calling chain:
account_scheduler_latency(struct task_struct *task, int usecs, int inter)
{
if (unlikely(latencytop_enabled)) /* the outtermost check */
__account_scheduler_latency(task, usecs, inter);
}
__account_scheduler_latency
account_global_scheduler_latency
if (!latencytop_enabled)
So, the inner check for latencytop_enabled is not necessary at all.
2. In clear_all_latency_tracing and now is called
clear_tsk_latency_tracing the check for latencytop_enabled is redundant
and buggy to some extent.
We have no reason to refuse clearing the /proc/$pid/latency if
latencytop_enabled is set to 0, considering that if we use latencytop
manually by echo 0 > /proc/sys/kernel/latencytop, then we want to clear
/proc/$pid/latency and failed.
Also we don't have such check in brother function
clear_global_latency_tracing.
Notes: These changes are only visible to users who set
CONFIG_LATENCYTOP and won't change user tool latencytop's behavior.
Link: http://lkml.kernel.org/r/20190226114602.16902-2-linf@wangsu.com
Signed-off-by: Lin Feng <linf@wangsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed
