[aarch64-port-dev ] [Roland Westrelin] Re: Aarch64 port for ZGC, so far

Andrew Haley aph at redhat.com
Mon Apr 15 10:53:00 UTC 2019

On 4/15/19 10:51 AM, Per Liden wrote:
> Btw, it's only a bit of a kludge if you're on an old kernel, that 
> doesn't have memfd_create() support (kernel < 3.17 and kernel < 4.14 
> when using large pages). With memfd_create() support it's pretty much 
> transparent, with no need to mount file system, etc.

I agree, but you still end up with aliases in the TLB. Given that the
L1 TLB is maybe 10-32 items in size, we really shouldn't be using
scarce resources if we can avoid doing so. This is something of a pain
point: Java tends to be memory heavy, with lots of pointer chasing,
and Arm cores tend to be a little smaller than Intel's.

Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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