RFR: 8194860: Cleanup Semaphore timed-wait time calculations

[David Holmes]

Take 2: webrev updated in place.

For OSXSemaphore I simply changed the existing timedwait method to take 
the single millis arg as used by the new PosixSemaphore so that calling 
code is correct for both cases. I also deleted the unnecessary 
currenttime() method. I chose not to implement the absolute timedwait 
because the conversion to a relative wait as needed by the kernel 
semaphore is non-trivial and as its unused it would be untested.

David

On 17/01/2019 2:58 pm, David Holmes wrote:
> Withdrawn temporarily.
> 
> The OS X changes were still being tested and they don't work. For some 
> reason we're using kernel semaphores on OS X and they seem to take a 
> relative timeout directly. That explains why they had a different API 
> but doesn't help with the fact that the calling code expects 
> OSXSemaphore and PosixSemaphore to have the same API.
> 
> David
> 
> On 17/01/2019 8:06 am, David Holmes wrote:
>> bug: https://bugs.openjdk.java.net/browse/JDK-8194860
>> webrev: http://cr.openjdk.java.net/~dholmes/8194860/webrev/
>>
>> Details in the bug report, but there was duplication in functionality 
>> with regards to timeout conversions/calculations, and the os_bsd.cpp 
>> code was broken due to OSXSemaphore and PosixSemaphore having 
>> different API's.
>>
>> Summary:
>> - expanded the API to take a relative timeout in millis as well as the 
>> existing absolute timeout as a timespec:
>>
>>    // wait until the given absolute time is reached
>>    bool timedwait(struct timespec ts);
>>    // wait until the given relative time elapses
>>    bool timedwait(int64_t millis);
>>
>> The millis version simply converts to a timespec and calls the other 
>> version e.g
>>
>> bool PosixSemaphore::timedwait(int64_t millis) {
>>    struct timespec ts;
>>    os::Posix::to_RTC_abstime(&ts, millis);
>>    return timedwait(ts);
>> }
>>
>> - added os::Posix::to_RTC_abstime to do the relative to absolute 
>> conversion using the existing routines in os::Posix used for 
>> PlatformEvent etc.
>>
>> - changed callsites to use new millis version
>>
>> - I had to rearrange the ifndef SOLARIS in os_posix.cpp to expose 
>> previously hidden code to Solaris. It isn't all needed by Solaris but 
>> I chose not to clutter things with too many ifdefs and only excluded 
>> things that really shouldn't be done on Solaris. Also needed to call 
>> os::Posix::init on Solaris.
>>
>> Testing (still in progress):
>> - mach 5 tiers 1 - 3 (Linux, Solaris, OS X, Windows)
>> - test/jdk/jdk/jfr (as suspend/resume is the user of the semaphore code)
>>
>> Thanks,
>> David