From: Vincent Guittot <vincent.guittot@linaro.org>
To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
linux-kernel@vger.kernel.org, tim.c.chen@linux.intel.com
Cc: joel@joelfernandes.org, Vincent Guittot <vincent.guittot@linaro.org>
Subject: [PATCH 2/2] sched: sched: Fix rq->next_balance time updated to earlier than current time
Date: Fri, 12 Nov 2021 11:04:58 +0100 [thread overview]
Message-ID: <20211112100458.7958-1-vincent.guittot@linaro.org> (raw)
From: Tim Chen <tim.c.chen@linux.intel.com>
In traces on newidle_balance(), this_rq->next_balance
time goes backward and earlier than current time jiffies, e.g.
11.602 ( ): probe:newidle_balance:(ffffffff810d2470) this_rq=0xffff88fe7f8aae00 next_balance=0x1004fb76c jiffies=0x1004fb739
11.624 ( ): probe:newidle_balance:(ffffffff810d2470) this_rq=0xffff88fe7f8aae00 next_balance=0x1004fb731 jiffies=0x1004fb739
13.856 ( ): probe:newidle_balance:(ffffffff810d2470) this_rq=0xffff88fe7f8aae00 next_balance=0x1004fb76c jiffies=0x1004fb73b
13.910 ( ): probe:newidle_balance:(ffffffff810d2470) this_rq=0xffff88fe7f8aae00 next_balance=0x1004fb731 jiffies=0x1004fb73b
14.637 ( ): probe:newidle_balance:(ffffffff810d2470) this_rq=0xffff88fe7f8aae00 next_balance=0x1004fb76c jiffies=0x1004fb73c
14.666 ( ): probe:newidle_balance:(ffffffff810d2470) this_rq=0xffff88fe7f8aae00 next_balance=0x1004fb731 jiffies=0x1004fb73c
It doesn't make sense to have a next_balance in the past.
Fix newidle_balance() and update_next_balance() so the next
balance time is at least jiffies+1.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
[Rebase]
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/fair.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a162b0ec8963..1050037578a9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -10138,7 +10138,10 @@ update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
/* used by idle balance, so cpu_busy = 0 */
interval = get_sd_balance_interval(sd, 0);
- next = sd->last_balance + interval;
+ if (time_after(jiffies+1, sd->last_balance + interval))
+ next = jiffies+1;
+ else
+ next = sd->last_balance + interval;
if (time_after(*next_balance, next))
*next_balance = next;
@@ -10974,6 +10977,8 @@ static int newidle_balance(struct rq *this_rq, struct rq_flags *rf)
out:
/* Move the next balance forward */
+ if (time_after(jiffies+1, this_rq->next_balance))
+ this_rq->next_balance = jiffies+1;
if (time_after(this_rq->next_balance, next_balance))
this_rq->next_balance = next_balance;
--
2.17.1
next reply other threads:[~2021-11-12 10:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-12 10:04 Vincent Guittot [this message]
2021-11-12 15:21 ` [PATCH 2/2] sched: sched: Fix rq->next_balance time updated to earlier than current time Peter Zijlstra
2021-11-15 19:40 ` Tim Chen
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