RFR: 8284950: Swappiness disables swap space usage

[Ioi Lam]

On Mon, 18 Apr 2022 09:07:31 GMT, xpbob <duke at openjdk.java.net> wrote:

> set memory.swappiness to 0,swap space will not be used 
> determine the value of memory.swappiness
> https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt
> 
> 
>     Memory Limit: 50.00M
>     Memory Soft Limit: Unlimited
>     Memory & Swap Limit: 100.00M
>     Maximum Processes Limit: 4194305 
> 
> =>
> 
>     Memory Limit: 50.00M
>     Memory Soft Limit: Unlimited
>     Memory & Swap Limit: 50.00M
>     Maximum Processes Limit: 4194305

src/java.base/linux/classes/jdk/internal/platform/cgroupv1/CgroupV1Subsystem.java line 155:

> 153:         long memswBytes = getLongValue(controller, "memory.memsw.limit_in_bytes");
> 154:         long swappiness = getLongValue(controller, "memory.swappiness");
> 155:         return (memswBytes > 0 && swappiness > 0);

Does this also need to be changed in the test?

https://github.com/openjdk/jdk/blob/c63fabe3d582ce0828b04b0224cea49aab5fedf3/test/lib/jdk/test/lib/containers/cgroup/MetricsTesterCgroupV1.java#L291-L296

-------------

PR: https://git.openjdk.java.net/jdk/pull/8285