On 7/29/10 5:57 PM, Jason Gunthorpe wrote:
You would need to modify ib_umem_get() to check for the VM_PFNMAP
flag and build the struct ib_umem similar to the proposed
ib_iomem_get(). However, the page reference counting/sharing issue
would need to be solved. I think there are kernel level callbacks
for this that could be used.
But in this case the pages are already mmaped into a user process,
there must be some mechanism to ensure they don't get pulled away?!
This is not virtual memory. It's real memory.
Though, I guess, what happens if you hot un-plug the PCI-E card that
has a process mmaping its memory?!
Exactly. The memory would have to be physically detached for it to get
'pulled away'
What happens if you RDMA READ from PCI-E address space that does not
have any device responding?
bus error.
Jason
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
