04.02.2018 5:32, Brandon Allbery wrote: > Also worth noting is that likely candidates for such pageouts include > long-lived daemons that are only needed, or which only need certain pages, > during startup/shutdown. So evicting only those pages to swap allows > optimal use of memory that would otherwise be wasted unnecessarily. > > Studying demand paging and unified page management is worth the effort. > Modern OSes, including Windows, make heavy use of this to optimize memory > usage --- but it means that old-style notions of process memory usage will > leave you wondering how the numbers make any sense. (I see this quite a > lot; most people still seem to think the basic unit of memory management is > a process, not a memory page, despite unified page management being over a > decade old and basic demand paging going back to 4BSD days.)
FreeBSD kernel does not try to "swapout" even long-lived sleeping daemons as a whole when it needs some free pages. Even if it needs to free more pages by paging out some of them, it tries to minimize such I/O operations by default and writes only minimal necessary amount of pages keeping the rest intact, when vm.swap_idle_enabled=0. _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
