Ok, the "lazy" version will be pushed.
Thank you .
On 1/22/2015 4:23 PM, Sergey Bylokhov wrote:
On 22.01.2015 13:42, mikhail cherkasov wrote:
Hi Anton, Sergey,
Anton advised today to implement eager initialization of EQ's logger
instead of lazy initialization of EQ's logger.
So now it will be initialized out of any AppContext's lock and I
thinks it's definitely better solution because
no ugly getLogger methods, less changes and now we know when and
where logger will be initialized.
Could you please review a new version:
http://cr.openjdk.java.net/~mcherkas/8065709/webrev.03/ ?
No, no , no. I completely disagree on this solution. Besides that it
not readable, it also contains an unobvious restrictions on
EventQueue class.
Lazy initialization is better, moreover we have such requests already:
https://bugs.openjdk.java.net/browse/JDK-6880089
Thanks,
Mikhail.
On 1/20/2015 8:14 PM, Sergey Bylokhov wrote:
On 20.01.2015 19:08, Anton V. Tarasov wrote:
Hi Mikhail,
Ok, you removed the new lock at least. Looks better now (no more
comments from me). Thank you!
Personally I prefered to remove this logging, but this version looks
fine also.
Regards,
Anton.
On 20.01.2015 17:26, mikhail cherkasov wrote:
Hi Anton,
please check new version:
http://cr.openjdk.java.net/~mcherkas/8065709/webrev.01/src/share/classes/java/awt/EventQueue.java.udiff.html
I applied changes advised by your in offline, the synchronization
and second check for null was removed.
PlatformLogger.getLogger is already synchronized and can be
treated as sync block and second check.
Thanks,
Mikhail.
On 1/19/2015 10:38 PM, Anton Tarasov wrote:
On 19/01/15 19:15, mikhail cherkasov wrote:
On 1/19/2015 5:59 PM, Anton V. Tarasov wrote:
Hi Mikhail,
It seems the problem is not limited to EventQueue only. Even if
you solve it for EventQueue, the EventQueue ctor may cause a
chain of calls where some other AWT class is first accessed and
initialized. What if it contains the same getLogger() call in a
static block?
it can, but currently EventQueue doesn't do such things.
I guess that it's nearly impossible to guarantee that AppContext
ctor will never ever call anything containing uninitialized loggers.
If you agree with this, then there should be a generic solution
for the deadlock.
What comes to my mind is the following. The deadlock happens
due to a reverse lock taking order. Can we change it?
In LogManager.getUserContext() it seems like the javaAwtAccess
lock scope can be narrowed down. Namely, we can move the
javaAwtAccess.getAppletContext() line out of it.
it's already done:
http://hg.openjdk.java.net/jdk9/dev/jdk/rev/83f20d8bc13a
Oh, thanks, I didn't read all the discussion the first time.
Well, I see there's another deadlock involving the
sun.util.logging.PlatformLogger class...
In which case the method implementation should be additionally
synchronized. For instance, we can use the getAppContextLock
for the whole body of the method. Is the method implemented
somewhere else except the AppContext class?
Will it work from your point of view? (Probably, I didn't take
into account all the details.)
All this tricky synchronizations was done on purpose, I believe
it was done for performance sake.
So I want to make as less changes as possible, it's better to
still miss couple cases then introduce a
new big issue in the last public update. Anyway, this fix plus
http://hg.openjdk.java.net/jdk9/dev/jdk/rev/83f20d8bc13a
should cover all cases, the only possible if EQ ctor will lead
to javaAwtAccess, but it doesn't.
Ok, I'm fine with the fix (it looks harmless). However, I can't
say I like it because it introduses new lock and breaks
consistency (in all the other cases we get loggers directly)...
I'd look for any better solution in an appropriate time slot.
Reagards,
Anton.
Regards,
Anton.
On 16.01.2015 17:18, mikhail cherkasov wrote:
Hi all,
JBS: https://bugs.openjdk.java.net/browse/JDK-8065709
Webrev: http://cr.openjdk.java.net/~mcherkas/8065709/webrev.00/
AppContext creation is guarder by getAppContextLockand, but
during AppContext creation
we also call EventQueue initialization, during EQ
initialization logger initialization happens
it acquires "javaAwtAccess". if "javaAwtAccess" is acquired
by other it can lead to deadlock:
T1 T2
start AppContext creation
acquire javaAwtAccess
acquire getAppContextLock
init EQ call getAppContext
init Logger waiting for getAppContextLock
waiting for javaAwtAccess
I applied the fix suggested in jbs comments by Petr.
I replaced eager logger initialization in EQ with lazy, so we
won't invoke Logger
during EQ initialization as result no deadlock.
Thanks,
Mikhail.
