RFR: 8237649: ZGC: Improved NUMA support when using small pages

erik.osterlund at oracle.com erik.osterlund at oracle.com
Fri Jan 24 14:58:01 UTC 2020


Hi Per,

Looks good.

Thanks,
/Erik

On 1/23/20 11:02 AM, Per Liden wrote:
> The NUMA allocation support in ZGC works as expected only when using 
> -XX:+UseLargePages. The reason is that, on Linux, small pages are 
> allocated at commit/fallocate time and is controlled by the NUMA 
> policy of the current thread, while large pages are allocated at page 
> fault time and is controlled by the NUMA policy of the memory range. 
> ZGC currently only sets up the NUMA policy for the memory range, which 
> has no effect on small pages (since they are allocated by tmpfs rather 
> than being anonymous mappings).
>
> We should fix this, so that the NUMA allocation support works equally 
> well for small pages.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8237649
> Webrev: http://cr.openjdk.java.net/~pliden/8237649/webrev.0
>
> /Per




More information about the hotspot-gc-dev mailing list