Hi > > Why drop (total_swap_pages == 0 && PageAnon(page)) condition? > > in embedded sysmtem, > > CONFIG_NORECLAIM is OFF (because almost embedded cpu is 32bit) and > > that anon move to inactive list is meaningless because it doesn't have swap. > > That was a mistake, kind of. Since all swap backed pages are on their > own LRU lists, we should not scan those lists at all any more if we are > out of swap space. > > The patch that fixes get_scan_ratio() adds that test. > > Having said that, with the nr_swap_pages==0 test in get_scan_ratio(), > we no longer need to test for that condition in shrink_active_list().
Oh I see! thank you for your kindful lecture. your implementation is very cute. > > below code is more good, may be. > > but I don't understand yet why ignore page_referenced() result at anon page > > ;-) > > On modern systems, swapping out anonymous pages is a relatively rare > event. All anonymous pages start out as active and referenced, so > testing for that condition does (1) not add any information and (2) > mean we need to scan ALL of the anonymous pages, in order to find one > candidate to swap out (since they are all referenced). > > Simply deactivating a few pages and checking whether they were referenced > again while on the (smaller) inactive_anon_list means we can find candidates > to page out with a lot less CPU time used. thanks, I understand, may be. - kosaki -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
