Patent ID: 7206906

Claim:
A method for copying data from a first physical page in a memory that is directly accessible to input/output devices to a second physical page in the memory, the method comprising: requiring that each input/output device first register an access to the memory by a physical address of the memory prior to the access of the memory, the input/output devices registering the access by recording a source of data in the memory being accessed and the physical address of each physical page of the memory being accessed, the recording being made in a page mapping structure; obtaining a lock on a page mapping structure corresponding to the first physical page thereby preventing new accesses to the first physical page by one of the input/output devices; disabling access by registered devices to the memory by signaling the registered devices to halt access to physical address space, the registered devices being devices that have registered for access to the first physical page using the page mapping structure; copying the data from the first physical page to the second physical page; and enabling access to the second physical page in the memory by signaling the registered input/output devices to resume accessing the physical address space and by releasing the lock on the page mapping structure.