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author | Lin Feng <linf@wangsu.com> | 2019-05-14 15:42:31 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-14 19:52:49 -0700 |
commit | 0cc75888dad112395df0ac755915ceb79811831c (patch) | |
tree | 96f90ffd7e02be7b99619dd7ca2d4d1bd338c5fb /kernel/latencytop.c | |
parent | 831246570d34692e0550da952d0655bdcc985419 (diff) | |
download | linux-0cc75888dad112395df0ac755915ceb79811831c.tar.gz |
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>
Diffstat (limited to 'kernel/latencytop.c')
-rw-r--r-- | kernel/latencytop.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/kernel/latencytop.c b/kernel/latencytop.c index 99a5b5f46dc5..bbde5614da71 100644 --- a/kernel/latencytop.c +++ b/kernel/latencytop.c @@ -71,9 +71,6 @@ void clear_all_latency_tracing(struct task_struct *p) { unsigned long flags; - if (!latencytop_enabled) - return; - raw_spin_lock_irqsave(&latency_lock, flags); memset(&p->latency_record, 0, sizeof(p->latency_record)); p->latency_record_count = 0; @@ -96,9 +93,6 @@ account_global_scheduler_latency(struct task_struct *tsk, int firstnonnull = MAXLR + 1; int i; - if (!latencytop_enabled) - return; - /* skip kernel threads for now */ if (!tsk->mm) return; |