Hi, 

   Recently,  we upgrade 8 MariaDB slaves from MariaDB 10.1.22 to MariaDB 10.2.6.

   In error log,  it frequent occurrence some innodb Note:

.............

 2017-06-26  9:01:03 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 6142ms. The settings might not be optimal. (flushed=16 and evicted

=0, during the time.)

2017-06-26  9:03:54 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 4584ms. The settings might not be optimal. (flushed=8 and evicted=

0, during the time.)

2017-06-26  9:05:58 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 4728ms. The settings might not be optimal. (flushed=8 and evicted=

0, during the time.)

2017-06-26  9:08:49 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 5016ms. The settings might not be optimal. (flushed=8 and evicted=

0, during the time.)

2017-06-26  9:09:12 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 4990ms. The settings might not be optimal. (flushed=8 and evicted=

0, during the time.)

2017-06-26  9:11:27 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 5387ms. The settings might not be optimal. (flushed=8 and evicted=

0, during the time.)

2017-06-26  9:14:43 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 6463ms. The settings might not be optimal. (flushed=0 and evicted=

0, during the time.)

2017-06-26  9:16:27 140022654363392 [Note] InnoDB: page_cleaner: 1000ms intended loop took 4031ms. The settings might not be optimal. (flushed=40 and evicted

=0, during the time.)  

............

Now, It have not affect the normal use,  but we could not confirm, it is our config problem or other  reasons?   

Please help confirm,  thanks.