Request for review: 6941923: RFE: Handling large log files produced by long running Java Applications

yumin.qi at oracle.com yumin.qi at oracle.com
Mon May 2 08:14:07 PDT 2011


  Jesper,

On 5/2/2011 7:05 AM, Jesper Wilhelmsson wrote:
> Yumin,
>
> Took a closer look this time and noticed that you introduce a fourth 
> new flag in addition to the three mentioned in the CR, -XX:GCLogFile. 
> I have to admit that I like the new name better than the old -Xloggc, 
> but do we really want to introduce a new flag with identical behavior 
> as the old?
>
In case we turn this flag into manageable, that is, we supply interface 
in JVMTI, it can be changed outside. Currently it is only a product 
flag. The log file name cannot be changed currently but future it should 
be changeable via JVMTI if debugger tools wants to change log rotation 
and file name.

> If we can deprecate the old flag and remove it in a few releases I 
> would be happy to endorse the new flag, but I suspect that -Xloggc is 
> quite heavily used in production environments.
>
>
> I am a bit puzzled by a change in ostream.cpp, in ostream_init_log():
>
>  807   if (gclog_or_tty != NULL && gclog_or_tty != tty) {
>  808     delete gclog_or_tty;
>  809   }
>
Yes, you are right. I add this part to prevent if it is already init'ed 
--- now it is only initailized once in vm creation.  This function is 
only called once at present. With log name changeable, it can be called 
multiples.

Thanks
Yumin
> Why is this needed? As far as I can tell gclog_or_tty will never have 
> a value here, the only assignment to that variable is made on the next 
> line in the same function and the function will only be called once 
> during initialization of the jvm. Have you seen cases where this 
> delete is executed?
> /Jesper
>
>
> On 04/29/2011 07:15 PM, yumin.qi at oracle.com wrote:
>> Jesper,
>>
>> Thanks. Deleted the comments part, this is the new version:
>>
>> http://cr.openjdk.java.net/~minqi/6941923/webrev.02
>>
>> Thanks
>> Yumin
>>
>> On 4/29/2011 5:25 AM, Jesper Wilhelmsson wrote:
>>> Yumin,
>>>
>>> In ostream.hpp lines 199 - 215 you have added a block of code that is
>>> commented out. Personally I don't think we should have code that is
>>> commented out in there unless there is a good documentation reason 
>>> for it. I
>>> don't see such a reason here.
>>>
>>> Looks good otherwise.
>>> /Jesper
>>>
>>>
>>>
>>> On 04/28/2011 11:18 PM, yumin.qi at oracle.com wrote:
>>>> Hi,
>>>>
>>>> Need your review on the second time changes:
>>>>
>>>> http://cr.openjdk.java.net/~minqi/6941923/webrev.01
>>>>
>>>> Any comments on the revised version? thanks in advance.
>>>>
>>>> Yumin
>>>>


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