[9] RFR (XS): C2: continuous CallSite relinkage eventually disables compilation for a method

[Vladimir Kozlov]

It will not work for AOT nmethods which have not_used state.

Vladimir

On 1/26/17 8:47 AM, Vladimir Ivanov wrote:
> http://cr.openjdk.java.net/~vlivanov/8173338/webrev.00/
> https://bugs.openjdk.java.net/browse/JDK-8173338
>
> The fix for JDK-7177745 disabled deoptimization count update when it happens due to CallSite.target change.
>
> There was one case missed though: the count is still updated when compilation fails due to a dependency becoming invalid
> during the compilation.
>
> The fix is to avoid the update when recompilation fails due to call_site_target dependency failure.
>
> Also, added a check in CodeCache::make_marked_nmethods_not_entrant() to avoid repeated nmethod::make_not_entrant() calls
> on nmethods which are already not entrant. Otherwise, the check is performed under Patching_lock inside
> nmethod::make_not_entrant_or_zombie() for every non-entrant method in the code cache.
>
> Testing: regression test, RBT (in progress)
>
> Thanks!
>
> Best regards,
> Vladimir Ivanov