From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Valentin Schneider <vschneid@redhat.com>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
Aashish Sharma <shraash@google.com>,
Vineeth Pillai <vineeth@bitbyteword.org>
Subject: [PATCH] sched/deadline: Do not start hrtick if its disabled for DL
Date: Tue, 12 Nov 2024 01:22:39 +0000 [thread overview]
Message-ID: <20241112012240.1887813-1-joel@joelfernandes.org> (raw)
Fix an issue where high-resolution timers causes aggressive preemptions,
leading to increased idle times in CFS tasks (which are inside the DL
server). The problem was traced to improper usage of hrtick_enabled(),
which could start high-resolution ticks unexpectedly causing repeated
preemptions.
The fix replaces this call with hrtick_enabled_dl(), aligning it with
scheduler feature checks.
Reported-by: Aashish Sharma <shraash@google.com>
Reported-by: Vineeth Pillai <vineeth@bitbyteword.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
kernel/sched/deadline.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index b216e6deeac4..d46502b9ce58 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2121,7 +2121,7 @@ static struct task_struct *pick_next_task_dl(struct rq *rq)
if (!p->dl_server)
set_next_task_dl(rq, p, true);
- if (hrtick_enabled(rq))
+ if (hrtick_enabled_dl(rq))
start_hrtick_dl(rq, &p->dl);
return p;
--
2.47.0.277.g8800431eea-goog
next reply other threads:[~2024-11-12 1:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-12 1:22 Joel Fernandes (Google) [this message]
2024-11-12 7:51 ` Juri Lelli
2024-11-12 18:36 ` Joel Fernandes
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