Mark Lam's Blog

August 2007 Archives

What's the Diff?

In a comment for a previous blog entry, I was asked ...

Hi Mark,

Although my question does not directly have to do with VM Inspector, I have a question regarding phoneME advanced MR2. This is regarding revision 5512 - Fix for CR 6554965: crash in pthread_getattr_np calling JNI AttachCurrentThread Reviewed by Chris.

Can you disclose what's the investigation on CR 6554965? I've seem cvm segfault occasionally without any further debug messages. However, I do not have a reproducible case. I would like to understand what is CR 6554965 is about and whether that applies to the problem I have experienced with the cvm.

Thanks,
Steven

This is how I get the answer for that ...

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CVM: Why use the C or Java heap?

A comment in a previous blog asks ...

I'd love to hear the explanations on why specific things are on the Java heap vs. the malloc heap. In particular it seems like there are a lot of things outside the Java heap that need to refer to things inside the Java heap (e.g. jitted code) resulting in a potentially large number of roots when collecting garbage.
-- erikcorry

For those of you who haven't been following my blogs before, Erik is asking a specific question regarding the memory layout of data structures in the CVM Java virtual machine (aka the phoneME Advanced VM).

Erik, do you mean why specific things are in the C heap instead of the Java heap? Or do you mean why are specific things in the Java heap instead of the C heap? Well, let me answer both ...

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