Messages in this thread | | | Date | Sun, 3 Aug 1997 10:42:16 +0200 | From | Pavel Machek <> | Subject | Re: APM support for avoiding waking up laptops every few seconds? |
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> > It would be nice if the laptop feature to spin down the drive weren't > nearly completely defeated by Unix's intelligent memory management. I > know people have suggested (and implemented) disabling updating atime > as a solution, but i think that would only help a little. Really, all > disk activity should be avoided and delayed whenever the disk is spun > down. > > Ideally what i would like to see would be, > > 1 Just before the APM spins down the disk, a sync should be done. > Though i'm not actually sure there's any way to request such notice. > > 2 Whenever the disk is spun down sys_bdflush should be a noop > The idea being that eventually a read will wake up the disk and all > those dirty buffers will be flushed within five seconds. This will > suck up a lot buffers but if the free list is empty refill_freelist > will still work fine.
Hmm, this can be done in userland, and I did it in userland for ide drives. I guess I'll have to publish it.
> > 3 A lot better behaviour in keeping unused buffers around > Currently if i run the same program repeatedly i still occasionally > hear pages getting read. And if i run a program every 30s it has to > be paged in every time. > > I realize the buffer architecture has changed in 2.1 hopefully it has > improved on the last point. > > Incidentally if you're worried about buffers not being committed soon > enough and users losing critical data, frankly, hearing the disk spin > down is a pretty unambiguous interface indicating that if the machine > panicked right that moment any writes would be lost. Users can always > run `sync' if it's absolutely critical. > > greg
-- -- This is my little buggy signature... Pavel GCM d? s-: !g p?:+ au- a--@ w+ v- C++@ UL+++ L++ N++ E++ W--- M- Y- R+
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