RFR: 8257230: assert(InitialHeapSize >= MinHeapSize) failed: Ergonomics decided on incompatible initial and minimum heap sizes

Thomas Schatzl tschatzl at openjdk.java.net
Mon Nov 30 13:45:58 UTC 2020


On Sat, 28 Nov 2020 13:08:38 GMT, Jie Fu <jiefu at openjdk.org> wrote:

> Hi all,
> 
> Ergonomics for InitialHeapSize can be broken if the memory resource is limited by the administrator.
> For example, this assert [1] fired on our testing boxes.
> 
> It can be reproduced by the following two steps on Linux-64:
>   1) ulimit -v 8388608
>   2) java -XX:MinHeapSize=5g -version
> The reason was that limit_by_allocatable_memory() [2] returns a value less than MinHeapSize.
> 
> One more important fact is that this bug can be more common on Linux-32 systems.
> Since the virtual memory is limited to 3800M [3] on Linux-32, it can be always reproduced when MinHeapSize > 1900M.
> 
> Testing:
>   - tier1 ~ tier3 on Linux/x64
> 
> Thanks.
> Best regards,
> Jie
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/gc/shared/gcArguments.cpp#L96
> [2] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/runtime/arguments.cpp#L1907
> [3] https://github.com/openjdk/jdk/blob/master/src/hotspot/os/posix/os_posix.cpp#L567

I think the change is good, but please add a test for this.

E.g. vmTestbase/nsk/jvmti/Allocate/alloc001/alloc001.java shows how to run a command with an ulimit prepended.

-------------

Changes requested by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1492


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