Thanks. So there is no "specialized data structure" for tracking dirty pages, the page dirty status is tracked within the regular page cache hierarchy. And the

Thanks. So there is no "specialized data structure" for tracking dirty pages, the page dirty status is tracked within the regular page cache hierarchy. And the obvious in-line solution (use a wraparound counter for tracking dirty state, increase dirty values for new pages while writing out lower values) isn't easy because the tag is a bitfield. So the easiest solution would be to have two separate dirty markers (e.g. dirty_a and dirty_b), and have the writeout process toggle the new-dirty marker from A to B so it can safely write dirty_a pages without interference. And vice-versa for the next writeout. There is just one caveat with regards to the previous solution: pages that are already pending writeout still need to be locked. In the previous design, a write to a page already pending writeout could be duplicated into the new dirty queue. But since it seems that a page can exist only once in the page cache, it cannot be written to without possibly violating write barriers. So the write must block until the writeout process has un-dirtied the page. Armchair programming is fun, isn't it? :)