Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

On 05/16/2015 09:35 AM, Dmitry Samersoff wrote: Derek, Personally, I'm for volatile over explicit fence too. So I'll change the code if Peter don't have objections. There are no objections. There's one unneeded volatile store to .next field then in enqueue(), but it is followed by another

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

On 05/16/2015 02:38 PM, Peter Levart wrote: On 05/16/2015 09:35 AM, Dmitry Samersoff wrote: Derek, Personally, I'm for volatile over explicit fence too. So I'll change the code if Peter don't have objections. There are no objections. There's one unneeded volatile store to .next field

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Derek, Personally, I'm for volatile over explicit fence too. So I'll change the code if Peter don't have objections. -Dmitry On 2015-05-16 01:59, Derek White wrote: Hi Dmitry, Peter, I should read my email more frequently - I missed Dmitry's last webrev email. My comments on a

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Peter, Some comments below... On 5/14/15 3:50 AM, Peter Levart wrote: Hi Derek, On 05/13/2015 10:34 PM, Derek White wrote: Hi Peter, I don't have smoking gun evidence that your change introduces a bug, but I have some concerns... I did have a concern too, ... On 5/12/15 6:05 PM,

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Dmitry, Peter, I should read my email more frequently - I missed Dmitry's last webrev email. My comments on a preference for volatile over Unsafe are not a strong objection to using Unsafe fences. I just don't have enough experience with Unsafe fences yet to agree that this use is

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Peter, Could we just bail out on r == r.next? It gives us less accurate result, but I suspect that If we restart from head we need to flush all counters. As far I understand queue poller removes items one by one from a queue end so if we overtaken by queue poller we can safely assume that we

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

On 05/14/2015 10:11 PM, Peter Levart wrote: Hi Dmitry, ReferenceQueue is not really a queue, but a LIFO stack. Scanner is walking the stack from top (the 'head') to bottom (the last element pointing to itself). When poller(s) overtake the scanner, it actually means that the top of the

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Dmitry, ReferenceQueue is not really a queue, but a LIFO stack. Scanner is walking the stack from top (the 'head') to bottom (the last element pointing to itself). When poller(s) overtake the scanner, it actually means that the top of the stack has been eaten under scanner's feet while

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Peter, Thank you for the explanation! -Dmitry On 2015-05-14 23:35, Peter Levart wrote: On 05/14/2015 10:11 PM, Peter Levart wrote: Hi Dmitry, ReferenceQueue is not really a queue, but a LIFO stack. Scanner is walking the stack from top (the 'head') to bottom (the last element pointing

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Derek, On 05/13/2015 10:34 PM, Derek White wrote: Hi Peter, I don't have smoking gun evidence that your change introduces a bug, but I have some concerns... I did have a concern too, ... On 5/12/15 6:05 PM, Peter Levart wrote: Hi Dmitry, You iterate the queue then, not the

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

I also have some comments on Dmitry's code... On 05/13/2015 11:52 PM, Derek White wrote: Hi Dmitry, Some review comments below... On 5/12/15 1:10 PM, Dmitry Samersoff wrote: Everybody, Updated version: http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.03/ Now it iterates over

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Peter, I don't have smoking gun evidence that your change introduces a bug, but I have some concerns... On 5/12/15 6:05 PM, Peter Levart wrote: Hi Dmitry, You iterate the queue then, not the unfinalized list. That's more logical. Holding the queue's lock may pause reference handler and

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Dmitry, Some review comments below... On 5/12/15 1:10 PM, Dmitry Samersoff wrote: Everybody, Updated version: http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.03/ Now it iterates over queue and output result sorted by number of instances. FinalReference.java - Update copyright

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Everybody, Updated version: http://cr.openjdk.java.net/~dsamersoff/JDK-8059036/webrev.03/ Now it iterates over queue and output result sorted by number of instances. -Dmitry On 2015-05-07 00:51, Derek White wrote: Hi Dmitry, Staffan, Lots of good comments here. On the topic of what

Re: RFR(M,v3): JDK-8059036 : Implement Diagnostic Commands for heap and finalizerinfo

Hi Dmitry, You iterate the queue then, not the unfinalized list. That's more logical. Holding the queue's lock may pause reference handler and finalizer threads for the entire time of iteration. This can blow up the application. Suppose one wants to diagnose the application because he