RFR(xs): 8229967: Enable thread local handshakes on zero

[Severin Gehwolf]

Hi Robin,

On Wed, 2019-08-21 at 10:19 +0200, Robbin Ehn wrote:
> Hi all, please consider.
> 
> Zero can have handshakes enabled.
> This prepares the vm for removing global safepoints.
> 
> Built x64 and sanity tested. (should be platform independent)

Thanks for doing this. Zero bootcycles fine with this for me on x86_64.
So +1 from me.

> x86 do not build for me due to workaround_expand_exec_shield_cs_limit.

I've never tried 32 bit Zero on x86. Not sure if this was ever working.

Thanks,
Severin

> Thanks, Robbin
> 
> diff -r 7c20dcb59a68 src/hotspot/cpu/zero/globalDefinitions_zero.hpp
> --- a/src/hotspot/cpu/zero/globalDefinitions_zero.hpp	Mon Aug 19 13:43:51 2019 +0200
> +++ b/src/hotspot/cpu/zero/globalDefinitions_zero.hpp	Wed Aug 21 10:02:44 2019 +0200
> @@ -32,2 +32,4 @@
> 
> +#define THREAD_LOCAL_POLL
> +
>   #include <ffi.h>
> diff -r 7c20dcb59a68 src/hotspot/cpu/zero/globals_zero.hpp
> --- a/src/hotspot/cpu/zero/globals_zero.hpp	Mon Aug 19 13:43:51 2019 +0200
> +++ b/src/hotspot/cpu/zero/globals_zero.hpp	Wed Aug 21 10:02:44 2019 +0200
> @@ -78,3 +78,3 @@
> 
> -define_pd_global(bool, ThreadLocalHandshakes, false);
> +define_pd_global(bool, ThreadLocalHandshakes, true);