MmAllocateContiguousMemorySpecifyCache always fail in windows 7

hustzcj · Oct 21, 2009, 06:34 AM

Hi All,

I have inserted 4 PCI cards in my system, system memory is 1GB.
I used MmAllocateContiguousMemorySpecifyCache for getting DMA-able memory.
Each card need 15MB,this success in previous OS's(i.e. 2000, 2003 server, XP, Vista).
But in windows 7,this failed even I restart the computer.

But I added up to 2GB memory in my computer,this successed.
All the 4 chip can have a 15MB contiguous, cache-aligned memory,
no yellow exclamation point next to our device in Device Manager.

It seems that the memory management scheme of Windows 7 has changed.
When using the call MmAllocateContiguousMemorySpecifyCache(),
less contiguous memory is available when memory is not large enough.(i.e.1GB)
How to fix this? (the method that without adding memory in system)
does anyone know what changed in Windows 7 and why?

Any help is appreciated.Thanks.

Best Regards
hustzcj

~~CitySlicker~~ · Oct 21, 2009, 06:46 AM

here is a bit

Windows 7 memory management changes

hustzcj · Oct 21, 2009, 09:48 AM

I have found this before.But thank you also.

Oct 21, 2009, 06:34 AM	#1
hustzcj DriverHeaven Newbie Join Date: Oct 2009 Posts: 2 Rep Power: 0	MmAllocateContiguousMemorySpecifyCache always fail in windows 7 Hi All, I have inserted 4 PCI cards in my system, system memory is 1GB. I used MmAllocateContiguousMemorySpecifyCache for getting DMA-able memory. Each card need 15MB,this success in previous OS's(i.e. 2000, 2003 server, XP, Vista). But in windows 7,this failed even I restart the computer. But I added up to 2GB memory in my computer,this successed. All the 4 chip can have a 15MB contiguous, cache-aligned memory, no yellow exclamation point next to our device in Device Manager. It seems that the memory management scheme of Windows 7 has changed. When using the call MmAllocateContiguousMemorySpecifyCache(), less contiguous memory is available when memory is not large enough.(i.e.1GB) How to fix this? (the method that without adding memory in system) does anyone know what changed in Windows 7 and why? Any help is appreciated.Thanks. Best Regards hustzcj

Oct 21, 2009, 06:46 AM	#2
~~CitySlicker~~ Banned Join Date: Sep 2009 Location: Brisbane Australia Posts: 183 Rep Power: 0 System Specs	Re: MmAllocateContiguousMemorySpecifyCache always fail in windows 7 here is a bit Windows 7 memory management changes

Oct 21, 2009, 09:48 AM	Thread Starter #3
hustzcj DriverHeaven Newbie Join Date: Oct 2009 Posts: 2 Rep Power: 0	AW: MmAllocateContiguousMemorySpecifyCache always fail in windows 7 I have found this before.But thank you also.