RFR (S): 8014972: Crash with specific values for -XX:InitialCodeCacheSize=500K -XX:ReservedCodeCacheSize=500k

[Vladimir Kozlov]

Albert,

Please, place new flag in globals.hpp after InitialCodeCacheSize 
definition since they are related.

MinimumInitialCodeCacheSize should be MinimumCodeCacheSize.
We also asked to check upper limit since we can use > 2Gb (MAXINT) size 
for CodeCache.

Also your changes could be much simpler if you just add the check
(InitialCodeCacheSize < min_code_cache_size) before existing check 
(ReservedCodeCacheSize < InitialCodeCacheSize).

And, please, don't use different message for debug build.

'* 3' for debug build could be done as:

uint min_code_cache_size = MinimumInitialCodeCacheSize DEBUG_ONLY(* 3) + 
CodeCacheMinimumFreeSpace;

thanks,
Vladimir

On 6/20/13 4:02 AM, Albert Noll wrote:
> Hi,
>
> thanks for reviewing this small patch.
>
> Albert
>
> jbs: https://jbs.oracle.com/bugs/browse/JDK-8014972
> webrev: http://cr.openjdk.java.net/~anoll/8014972/webrev.00/
> <http://cr.openjdk.java.net/%7Eanoll/8014972/webrev.00/>
>
>
> Problem:
> If -XX:ReservedCodeCacheSize is set too small, the VM crashes when
> starting up.
>
> Solution:
> Introduce a minimum code cache size (ReservedCodeCacheSize) that
> guarantees that the VM can startup. The minimum code cache size is
> defined by a new parameter (MinimumInitialCodeCacheSize) that cannot be
> changed in product build. My reasoning for this is that smaller values
> make the JVM crash at startup. However, in a development build, the
> parameter can be changed.
>
> The current patch sets MinimumInitialCodeCacheSize to 400k for all
> platforms. On Solaris, MinimumInitialCodeCacheSize could be set to 300k
> and the VM still starts up. However, I am not sure if it makes sense to
> make MinimumInitialCodeCacheSize platform-dependent so that we can
> potentially save 100k on Solaris. If there is a reason, please let me know.
>
> Also note that the InitialCodeCacheSize must be > 0. The reason is that
> otherwise the following  assertion fails:
>
> Internal Error
> (/tmp/workspace/2-build-solaris-i586/jdk8/4767/hotspot/src/share/vm/memory/heap.cpp:50),
> pid=27190, tid=2
> #  assert(0 <= beg && beg < _number_of_committed_segments) failed:
> interval begin out of bounds
>
>
> Testing:
> With the current value of MinimumInitialCodeCacheSize, the VM starts up
> on all Windows, Linux, and Solaris.
>
> Note that we can still get exceptions (and the JVM cannot continue to
> execute) if the value for CodeCacheMinimumFreeSpace is to small (in that
> case, here is not enough space for adapters) .