How could VirtualAlloc fail (no mem) despite plenty of phys memory on WinMobile?

Question

I am routinely seeing VirtualAlloc calls to reserve memory fail. I'm requesting 2MB so that the allocations do not count against my per process virtual memory and instead use system shared memory. At the time of failure, the system reports having over 100 MB available in physical memory.

I'm running on a windows mobile 6.1 device. So far this is a device-specific problem. It works on many identical devices and fails on one device. I would like to be able to determine if other processes on this device are reserving shared memory and therefore preventing me from doing so. Not sure how i can do that though.

This is the doc I am relying on and I see nothing that would explain this problem: http://msdn.microsoft.com/en-us/library/aa908768.aspx

Any ideas? Thanks.

Answer 1

I'm tempted to say that VirtualAlloc has run out of (contiguous) virtual address space, at least as far as your process is concerned.

I'd first try to establish to which memory slot those previously successful VirtualAlloc chunks got mapped to, and based on that see whom I am fighting with for address space. You should be able to do this either programatically or by using a tool from William J. Blanke (or other similar tools.)