Large memory reporting

[Shachar Shemesh]

Hi list,

I have a Windows program that tries to find out how much memory it has 
at its disposal using "GlobalMemoryStatus". The machine has 4GB of 
physical memory and about 100MB of swap. GlobalMemoryStatus returns 2GB 
of physical memory and 0 available swap.

It seems the problem is at dlls/kernel/heap.c, around lines 1150. First 
we make sure we never report more than 2GB of total or available memory, 
and then we make sure that we never report more than 2GB combined 
available physical+swap memory (which effectively zeros the available 
swap if there is more than 2GB of available memory). The comment next to 
this is:
    /* work around for broken photoshop 4 installer */

While I understand the need for the workaround, this significantly 
reduces the usefulness of the whole function. My question:
Can we make these two rounding conditional on the application not 
wishing to work with more than 2GB? I.e. - can we let applications that 
were linked with LARGEADDRESSAWARE see the true state of the machine?

If so, is there a way for me, when at the heap.c code, to know whether 
that flag was set on loading the current process?

Shachar

[Dmitry Timoshkov]

"Shachar Shemesh"  wrote:
> If so, is there a way for me, when at the heap.c code, to know whether 
> that flag was set on loading the current process?

(copied from dlls/ntdll/loader.c):

PEB *peb = NtCurrentTeb()->Peb;
IMAGE_NT_HEADERS *nt = RtlImageNtHeader( peb->ImageBaseAddress );

if (nt->FileHeader.Characteristics & IMAGE_FILE_LARGE_ADDRESS_AWARE)
{
    return full_address_range_of_the_application;
}
else
    return 2Gb_of_adderess_space;

or even better reimplement GlobalMemoryStatus via VirtualQuery and
leave all system dependent code to ntdll.NtQueryVirtualMemory.