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

[Vladimir Kozlov]

Also it could be confusing that MinimumCodeCacheSize is less then 
CodeCacheMinimumFreeSpace. So the definition should be:

develop(uintx, MinimumInitialCodeCacheSize, 900*K,

And in arguments.cpp you need to do next since CodeCacheMinimumFreeSpace 
could be set on command line:

uint min_code_cache_size = (K * NOT_DEBUG(400) DEBUG_ONLY(1200)) + 
CodeCacheMinimumFreeSpace;
min_code_cache_size = MIN2(MinimumCodeCacheSize, min_code_cache_size);

thanks,
Vladimir

On 6/20/13 1:27 PM, Vladimir Kozlov wrote:
> 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) .