Alan writes: > In conclusion, I think it's time that we change M_NOWAIT so that it doesn't > dig any deeper into the cache/free page queues than M_WAITOK does and > reintroduce a M_USE_RESERVE-like flag that says dig deep into the > cache/free page queues. The trouble is that we then need to identify all > of those places that are implicitly depending on the current behavior of > M_NOWAIT also digging deep into the cache/free page queues so that we can > add an explicit M_USE_RESERVE.
find /usr/src/sys | xargs grep M_NOWAIT | wc -l 2101 Sounds like a lot of work that would need to happen atomically. Would this work: M_NO_WAIT do not sleep, do not dig deep unless M_USE_RESERVE also set M_USE_RESERVE dig deep M_NOWAIT M_NO_WAIT | M_USE_RESERVE (deprecated) New code avoids using M_NOWAIT. Existing code continues working the same way. As time permits, old code is converted to new flags. Eventually M_NOWAIT goes away. Pro: the amount of code that needs to change atomically is much smaller. Con: (1) Have to remember (or look up) difference between M_NOWAIT and M_NO_WAIT. Maybe calling the new flag M_NO_SLEEP would help? (2) Would M_NOWAIT really ever go away? The spl() calls haven't, even after some cage rattling. _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
