linux kernel page cache : struct address_space

linux kernel page cache : struct address-space

quoted from : professional linux kernel architecture by Wolfgang Mauerer, page 956.

How do address spaces fit into the structures of the page cache?

1. pages in main memory are allocated to each address space.

2. The backing store specifies the sources from which the address space pages are filled. Address spaces relate to the virtual address space of the processor and are mapping of the segment managed by the processor in virtual memory and the corresponding positions on a source device (using a block device)

3. If a position in virtual memory that is NOT associated with a physical page in memory is accessed, the kernel can refer to the address space structure to discover from WHERE the data must be read.

4. to support data transfer, each address space provides a set of operation ( in the form of function pointers) to permit interaction between the two sides of address space. ie.: to read a page from a block device or filesystem, or to write back a modified page.