Messages in this thread Patch in this message | | | From | Vincent Guittot <> | 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 |
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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
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