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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Scott Wood <swood@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.19 03/25] sched/core: Don't skip remote tick for idle CPUs
Date: Sat, 22 Feb 2020 21:23:17 -0500	[thread overview]
Message-ID: <20200223022339.1885-3-sashal@kernel.org> (raw)
In-Reply-To: <20200223022339.1885-1-sashal@kernel.org>

From: Scott Wood <swood@redhat.com>

[ Upstream commit 488603b815a7514c7009e6fc339d74ed4a30f343 ]

This will be used in the next patch to get a loadavg update from
nohz cpus.  The delta check is skipped because idle_sched_class
doesn't update se.exec_start.

Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/1578736419-14628-2-git-send-email-swood@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/sched/core.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2befd2c4ce9e6..3c7e039eae9a1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3117,22 +3117,24 @@ static void sched_tick_remote(struct work_struct *work)
 	 * statistics and checks timeslices in a time-independent way, regardless
 	 * of when exactly it is running.
 	 */
-	if (idle_cpu(cpu) || !tick_nohz_tick_stopped_cpu(cpu))
+	if (!tick_nohz_tick_stopped_cpu(cpu))
 		goto out_requeue;
 
 	rq_lock_irq(rq, &rf);
 	curr = rq->curr;
-	if (is_idle_task(curr) || cpu_is_offline(cpu))
+	if (cpu_is_offline(cpu))
 		goto out_unlock;
 
 	update_rq_clock(rq);
-	delta = rq_clock_task(rq) - curr->se.exec_start;
 
-	/*
-	 * Make sure the next tick runs within a reasonable
-	 * amount of time.
-	 */
-	WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
+	if (!is_idle_task(curr)) {
+		/*
+		 * Make sure the next tick runs within a reasonable
+		 * amount of time.
+		 */
+		delta = rq_clock_task(rq) - curr->se.exec_start;
+		WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
+	}
 	curr->sched_class->task_tick(rq, curr, 0);
 
 out_unlock:
-- 
2.20.1


  parent reply	other threads:[~2020-02-23  2:30 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-23  2:23 [PATCH AUTOSEL 4.19 01/25] ipmi:ssif: Handle a possible NULL pointer reference Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 02/25] drm/msm: Set dma maximum segment size for mdss Sasha Levin
2020-02-23  2:23 ` Sasha Levin [this message]
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 04/25] dax: pass NOWAIT flag to iomap_apply Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 05/25] mac80211: consider more elements in parsing CRC Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 06/25] cfg80211: check wiphy driver existence for drvinfo report Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 07/25] s390/zcrypt: fix card and queue total counter wrap Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 08/25] qmi_wwan: re-add DW5821e pre-production variant Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 09/25] qmi_wwan: unconditionally reject 2 ep interfaces Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 10/25] arm/ftrace: Fix BE text poking Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 11/25] ARM: dts: sti: fixup sound frame-inversion for stihxxx-b2120.dtsi Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 12/25] soc/tegra: fuse: Fix build with Tegra194 configuration Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 13/25] net: ena: fix potential crash when rxfh key is NULL Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 14/25] net: ena: fix uses of round_jiffies() Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 15/25] net: ena: add missing ethtool TX timestamping indication Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 16/25] net: ena: fix incorrect default RSS key Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 17/25] net: ena: rss: fix failure to get indirection table Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 18/25] net: ena: rss: store hash function as values and not bits Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 19/25] net: ena: fix incorrectly saving queue numbers when setting RSS indirection table Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 20/25] net: ena: ethtool: use correct value for crc32 hash Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 21/25] net: ena: ena-com.c: prevent NULL pointer dereference Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 22/25] enic: prevent waking up stopped tx queues over watchdog reset Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 23/25] cifs: Fix mode output in debugging statements Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 24/25] bcache: ignore pending signals when creating gc and allocator thread Sasha Levin
2020-02-23  2:23 ` [PATCH AUTOSEL 4.19 25/25] cfg80211: add missing policy for NL80211_ATTR_STATUS_CODE Sasha Levin

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