[codermike]

It calls malloc once or twice when you resume a snapshot. The first malloc includes core persistent state (e.g. memory stats counters, etc), and global variables in the script. If there is any heap in the snapshot, the second malloc is for the initial heap.

Then it calls malloc when you call from C in JS -- about 300B by default. This is to allocate the core registers and virtual stack. It frees it when the JS has fully completed and control returns to the host.

Then it also calls malloc each time it runs out of space in the managed heap and needs to expand. By default these will be 256B chunks. If you use a lot of heap space, maybe you want to increase this chunk size to reduce overhead here.

And it calls malloc about once or twice each time there is a GC collection, regardless of heap size.