RFR (XS) 8061467: Add UseLargePages to TestNUMAPageSize

[Per Liden]

On 08/13/2018 11:41 AM, Thomas Schatzl wrote:
> Hi,
> 
>    while testing this patch before push it seems like the problem is ZGC
> which does not fall back to using small pages (which I did not know).
> 
>> [5.048s][error][gc,init] Not enough space available on the backing
> filesystem to hold the current max
>> [5.048s][error][gc,init] Java heap size (128M). Forcefully lowering
> max Java heap size to 0M (0%).
>> Error occurred during initialization of VM
>> java.lang.OutOfMemoryError: Java heap too small
> 
> I will hold off pushing this before this issue has been resolved in one
> way or the other.

UseNUMA is enabled by default in ZGC, so it's tested frequently anyway. 
I guess the easiest solution is to just not run this test when ZGC is 
enabled, something like this:

diff --git a/test/hotspot/jtreg/gc/TestNUMAPageSize.java 
b/test/hotspot/jtreg/gc/TestNUMAPageSize.java
--- a/test/hotspot/jtreg/gc/TestNUMAPageSize.java
+++ b/test/hotspot/jtreg/gc/TestNUMAPageSize.java
@@ -27,7 +27,8 @@
   * @summary Make sure that start up with NUMA support does not cause 
problems.
   * @bug 8061467
   * @requires vm.opt.AggressiveOpts != true
- * @run main/othervm -Xmx128m -XX:+UseNUMA TestNUMAPageSize
+ * @requires vm.gc != "Z"
+ * @run main/othervm -Xmx128m -XX:+UseNUMA -XX:+UseLargePages 
TestNUMAPageSize
   */

  public class TestNUMAPageSize {


cheers,
Per


> 
> Thanks,
>    Thomas
> 
> On Mon, 2018-08-13 at 10:23 +0200, Thomas Schatzl wrote:
>> Hi,
>>
>> On Mon, 2018-08-13 at 09:58 +0200, Per Liden wrote:
>>> Hmm, I suspect this might fail on many Linux systems, since it
>>> might require configuring the huge page pool with enough pages.
>>
>>    from my understanding -XX:+UseLargePages will just give some
>> warnings
>>   at startup if it can not allocate pages. It will not fail.
>>
>> Assuming that the intent is to check whether when trying to use large
>> pages (and the machine is properly configured), does not in any way
>> make the VM crash, the warnings can be ignored.
>>
>> I am not aware there is a way to run tests on machines only that have
>> the property "properly configured large pages" at this time.
>>
>> Thanks,
>>    Thomas
>>
>