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
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