Request for review: 8020530 Non heap memory size calculated incorrectly (original) (raw)

Vladimir Kempik vladimir.kempik at oracle.com
Wed Jan 22 06:16:15 PST 2014

Hello everyone, do you think this patch could be applicable to jdk7 and jdk6 as well ?

There is little difference between jdk7 and jdk8 here, two asserts were removed from jdk8. asserts shouldn't be triggered in product build and patch wouldn't do any harm anyway.

// if any one of the memory pool has undefined init_size or max_size, // set it to -1 if (has_undefined_init_size) { total_init = (size_t)-1; } if (has_undefined_max_size) { total_max = (size_t)-1; }

// In our current implementation, we make sure that all non-heap // pools have defined init and max sizes. Heap pools do not matter, // as we never use total_init and total_max for them. assert(heap || !has_undefined_init_size, "Undefined init size"); assert(heap || !has_undefined_max_size, "Undefined max size");

MemoryUsage usage((heap ? InitialHeapSize : total_init), total_used, total_committed, (heap ? Universe::heap()->max_capacity() : total_max));

Thanks Vladimir.

On 21.08.2013 18:37, Coleen Phillimore wrote:

Looks good, thanks! Coleen On 8/21/2013 6:40 AM, Vladimir Kempik wrote: Thanks everyone for comments.

Here is updated webrev http://cr.openjdk.java.net/~vkempik/8020530/webrev.01/ Vladimir. On 21.08.2013 1:52, Mandy Chung wrote:

On 8/20/2013 5:38 AM, Staffan Larsen wrote: That doesn't make a lot of sense to me. Why would a pool have undefined values? The Metaspace pool has no max value (unless you specify -XX:MaxMetaspaceSize=), thus undefined.

If a subset of pools have undefined values why report completely fallacious values of -1? The javadoc for MemoryUsage says getMax() returns -1 if the maximum memory size is undefined. Yes the spec allows implementation of memory pools with undefined max. "used" and "committed" must have a value and the "committed" memory is guaranteed to be available for the VM to use. "max" will give an idea of the upper bound how much memory can be allocated from it; however, there is no guarantee that amount of memory is available for the VM. It also isn't clear how this relates to the "committed" value in the failure. What gets reported now? I guess there can still be a committed value even if we don't have a max value for how much we might commit in the future: used <=_ _committed <= max._ _The MemoryUsage constructor throws IAE if committed > max if max is defined. Perhaps it would be better if max should be Long.MAXVALUE if undefined (a different issue than this bug). Mandy /Staffan Thanks, David

Thanks, Vladimir

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