Re: How to allocate a very big block of contiguous (and unpaged) memory in a specified address-range

Device Manager can show you resource allocations including memory, if you're willing to do that inspection by hand.


<verbiest@xxxxxxxxx> wrote in message news:930f0c0a-e578-4ef8-a17e-557d332c427e@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
You realize that you're not the only thing in the system that needs memory
below the 4GB line right? Other 32-bit devices do and I'm sure there are
some reasons why the kernel and HAL do as well. There's also generally a
large physical address space hole reserved for the PCI bus that's below 4GB.
See some of the earlier threads about why folks cannot see all of the 4GB in
their machines.

Is there a way to list the devices that allocate memory below 4GB? For
instance if I encounter memory fragmentation in virtual memory, I can
use VirtualQuery to get a view of the memory usage (or use a memory
profiler). Is there a similar mechanism to get a view on the physical
memory?

If you had a 64-bit DMA capable device then this might be easier. If your
device supported 64-bit scatter gather DMA for this large buffer (I.e. if
you could give it a list of physical addresses that represented the buffer
and it did the mapping internally) then this would probably be a trivial
undertaking.

There are plans (long term) to make a new generation of the board.
This is definitely something that should be considered.

Is this for a special purpose system? Or are you expecting to sell the card
and driver for folks to plug into any system?

It is for a special purpose system. We sell the system as a whole, so
we can choose all components and configure it ourselves.

Thanks for your time.
Kristof

.

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