Mimalloc attempts to allocate 33 MB shortly after thread start, prints spurious warning when it fails

[Jarred-Sumner]

On start when several threads are spawned, the following warning message is printed when using the debug build of mimalloc:

_mi_warning_message("unable to allocate aligned OS memory directly, fall back to over-allocation (size: 0x%zx bytes, address: %p, alignment: 0x%zx, commit: %d)\n", size, p, alignment, commit);

This warning message is not always actionable because (in this case) the developer didn't ask to allocate 33 MB. In my case, I care because it causes tests which read from stdout/stderr to fail.

Stepping through in a debugger, we can see the requested size is 64 bytes:

This is the stack trace:

When it reaches the warning, size & alignment seem to be 33,554,432:

Should this warning be silenced? Or does it point to a real problem and if so, what kinds of action can be taken (reduce the stack size of the application?)