Hi Marcus,
Looks good!
One minor thing that you don't need to fix if you don't want to:
I would use:
class ConfigurationLock {
...
debug_only(static bool current_thread_has_lock();)
};
to declare the this function in the class, then I would move the definition
outside of it (since it's sits inside ASSERT macros).
#ifdef ASSERT
bool ConfigurationLock::current_thread_has_lock() {
return _locking_thread_id == os::current_thread_id();
}
#endif
I just find it easier to read the class declaration without the macros inside
of the class declaration (and since this is debug code, there is no real use of
defining inline). As I said, you don’t need to fix this and to post another
webrev.
Good work!
/Markus
-----Original Message-----
From: Marcus Larsson
Sent: den 15 december 2015 11:25
To: serviceability-dev@openjdk.java.net
Cc: hotspot-runtime-...@openjdk.java.net
Subject: Re: RFR: 8145083: Use semaphore instead of mutex for synchronization
of Unified Logging configuration
Hi,
New webrev:
http://cr.openjdk.java.net/~mlarsson/8145083/webrev.03/
Incremental:
http://cr.openjdk.java.net/~mlarsson/8145083/webrev.02-03/
ConfigurationLocker renamed to ConfigurationLock to avoid confusion with the
MutexLocker family of classes.
Semaphore and locking thread id moved into the ConfigurationLock; added a
function to check if current thread has the lock when asserts are enabled.
Regards,
Marcus
On 2015-12-14 16:30, Marcus Larsson wrote:
> Hi again,
>
> Made some changes to the patch after feedback from Markus Grönlund.
> The ConfigurationLocker and the semaphore have been moved out of the
> LogConfiguration.hpp and into the .cpp instead. The lock is only used
> internally by the LogConfiguration so this makes sense. It simplifies
> the LogConfiguration interface and hides the details of the locking
> under the hood.
>
> New webrev:
> http://cr.openjdk.java.net/~mlarsson/8145083/webrev.02/
>
> Incremental:
> http://cr.openjdk.java.net/~mlarsson/8145083/webrev.01-02/
>
> Thanks,
> Marcus
>
> On 2015-12-14 15:53, Marcus Larsson wrote:
>> Hi,
>>
>> New webrev:
>> http://cr.openjdk.java.net/~mlarsson/8145083/webrev.01/
>>
>> Incremental:
>> http://cr.openjdk.java.net/~mlarsson/8145083/webrev.00-01/
>>
>> Changes:
>> * Introduced the ConfigurationLocker class for automatic wait/signal
>> in constructor/destructor just like a MutexLocker.
>> * Added an assert to verify that the "lock" is held by the current
>> thread when calling configure_output.
>> * Made the config-string functions in LogOutput protected and
>> LogConfiguration a friend of LogOutput to prevent incorrect usage of
>> these functions. These functions should typically only be used inside
>> configure_output, which now ensures that the lock is held.
>>
>> Thanks,
>> Marcus
>>
>>
>> On 2015-12-14 11:13, Marcus Larsson wrote:
>>> Hi,
>>>
>>> Please review the following patch to use a semaphore instead of a
>>> mutex for the synchronization of log configuration. Using a mutex
>>> requires some parts of the VM to be initialized, whereas the
>>> semaphores can be used right from the start. This simplifies the
>>> code and allows very early log configuration without special cases
>>> for early configuration vs reconfiguration after VM init.
>>>
>>> Webrev:
>>> http://cr.openjdk.java.net/~mlarsson/8145083/webrev.00/
>>>
>>> Issue:
>>> https://bugs.openjdk.java.net/browse/JDK-8145083
>>>
>>> Thanks,
>>> Marcus
>>
>
