A method for data transfer includes receiving in an input/output (I/O) operation a first segment of data to be written to a specified virtual address in a host memory. Upon receiving the first segment of the data, it is detected that a first page that contains the specified virtual address is swapped out of the host memory. At least one second page of the host memory is identified, to which a second segment of the data is expected to be written. Responsively to detecting that the first page is swapped out and to identifying the at least one second page, at least the first and second pages are swapped into the host memory. After swapping at least the first and second pages into the host memory, the data are written to the first and second pages.