linux-kernel - Re: thousands of kworker processes with 4.7.x and 4.8-rc*

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Date:   Fri, 23 Sep 2016 22:23:17 +0900
From:   Tomasz Chmielewski <mangoo@...g.org>
To:     LKML <linux-kernel@...r.kernel.org>
Subject: Re: thousands of kworker processes with 4.7.x and 4.8-rc*

On 2016-09-19 16:08, Tomasz Chmielewski wrote:
> On several servers running 4.7.x and 4.8-rc6/7 kernels I'm seeing
> thousands of kworker processes.
> # ps auxf|grep -c kworker
> 2104
> Load average goes into hundreds on a pretty much idle server (biggest
> CPU and RAM consumers are probably SSHD with one user logged in and
> rsyslog writing ~1 line per minute):
> # uptime
>  06:58:56 up 26 min,  1 user,  load average: 146.11, 215.46, 105.70
> # uptime
>  06:59:48 up 26 min,  1 user,  load average: 305.20, 240.84, 120.25
> Sometimes seeing lots of them in "D" state:
> root     19474  0.0  0.0      0     0 ?        D    06:54   0:00  \_
> [kworker/0:208]
> root     19475  0.0  0.0      0     0 ?        D    06:54   0:00  \_
> [kworker/0:209]


I did some experiments to see when the problem first appeared. Thousands 
of kworker processes start to show up in 4.7.0-rc5.

kernel version | kworker count after boot
-------------------------------------------
4.6.3 	        37
4.6.4 	        47
4.6.5 	        46
4.6.6 	        49
4.6.7 	        49
4.7.0-rc1 	46
4.7.0-rc2 	49
4.7.0-rc3	45
4.7.0-rc4	47
4.7.0-rc5	1592
4.7.0-rc6	1714
4.7.0-rc7 	1955
4.7.0 	        2088
4.7.1 	        1222
4.7.2 	        1699
4.7.3           1446
4.7.4 	        1781
4.8-rc1 	(not tested)
4.8-rc2 	2012
4.8-rc3 	1696
4.8-rc4 	1210
4.8-rc5 	1890
4.8-rc6 	1657
4.8-rc7 	1647


Tomasz Chmielewski
https://lxadm.com