RFR(XS): 8194232: Container memory not properly recognized.

[Bob Vandette]

I just read that unlimited may be one of these possible values depending on Kernel version.

LONG_MAX (Linux Kernel Version < 3.1.2)
ULONG_MAX (3.12 <= Linux Kernel Version < 3.19)
LONG_MAX / pagesize * pagesize (Linux Kernel Version >= 3.19)

Assuming os::page_size() is initialized before the container init, we should calculate
the unlimited value based on this and take the ULONG_MAX situation into consideration.

Bob.


> On Dec 27, 2017, at 6:24 AM, Lindenmaier, Goetz <goetz.lindenmaier at sap.com> wrote:
> 
> Hi Martin,
> 
> Yes, I also figured that the constant is one system page less than max long.
> If the system pages are > 64K, this constant will be too small, again.
> But I'm not sure whether adding 8 zeros is right thing to do in ramp down phase.
> 
> Best regards,
>  Goetz.
> 
> 
>> -----Original Message-----
>> From: Doerr, Martin
>> Sent: Mittwoch, 27. Dezember 2017 12:10
>> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; hotspot-runtime-
>> dev at openjdk.java.net
>> Subject: RE: RFR(XS): 8194232: Container memory not properly recognized.
>> 
>> Hi Götz,
>> 
>> thanks for fixing it.
>> 
>> I wonder if 4 zeroes will be sufficient on all linux distros in the long run. Does
>> anything speak against using e.g. 8 zeroes?
>> 
>> Best regards,
>> Martin
>> 
>> 
>> -----Original Message-----
>> From: hotspot-runtime-dev [mailto:hotspot-runtime-dev-
>> bounces at openjdk.java.net] On Behalf Of Lindenmaier, Goetz
>> Sent: Mittwoch, 27. Dezember 2017 11:38
>> To: hotspot-runtime-dev at openjdk.java.net
>> Subject: RFR(XS): 8194232: Container memory not properly recognized.
>> 
>> Hi
>> 
>> Please review and sponsor this tiny fix. It needs to go to jdk10.
>> http://cr.openjdk.java.net/~goetz/wr17/8194232-
>> ppcle_unlimited/webrev.01/
>> 
>> TestAggressiveHeap.java fails because the container recognition
>> misinterprets the available memory size. On SLES 12.1 ppc64le,
>> GET_CONTAINER_INFO() sets memlimit to 0x7FFFFFFFFFFF0000. This
>> is compared to UNLIMITED_MEM == 0x7FFFFFFFFFFFF000, making
>> the VM believe memory is _not_ unlimited.
>> 
>> Best regards,
>>  Goetz.
>