Re: 5.7-rc0: kswapd eats cpu during a disk test?!

From: Vlastimil Babka
Date: Mon Jun 01 2020 - 04:55:28 EST


+CC linux-mm

On 5/31/20 12:34 PM, Pavel Machek wrote:
> Hi!
>
> This is simple cat /dev/sda > /dev/zero... on thinkpad x60 (x86-32),
> with spinning rust.
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> 1000 root 20 0 0 0 0 R 53.3 0.0 57:34.93 kswapd0
> 27897 root 20 0 6976 580 536 R 44.5 0.0 1:44.53 cat
>
> It keeps both CPUs busy... and I don't think that's right.

Does an older kernel behave differently here?