Terry Lambert wrote: > Poul-Henning Kamp wrote: > > In message <[EMAIL PROTECTED]>, Peter Wemm writes: > > >As you said, _sleeping_ is the problem. M_WAITOK means "you may sleep if > > >you like". ie: it is a time bomb waiting for the right low memory condit ion > > >which will then explode with a 100% authentic crash or lock up. > > > > > >Pretend it said M_SLEEPOK instead of M_WAITOK. > > > > Uhm, I'm actually seeing the opposite behaviour as well: after I > > changed the md(4) driver to use M_NOWAIT I still see malloc/zalloc > > sleeping... > > I'm with Poul on this one, Peter: M_WAITOK doesn't mean what > you think it means: it's doesn't mean tsleep may be called, > and M_NOWAIT doesn't mean tsleep() _won't_ be called, in > practice.
No, it is exactly what it means, eg: if (!(flags & M_NOWAIT)) KASSERT(curthread->td_intr_nesting_level == 0, ("malloc(M_WAITOK) in interrupt context")); tsleep() in interrupt context is the kiss-of-death. M_NOWAIT means "you must not call tsleep!", which is what I have been saying all along. There is a known bug in UMA where it recurses and calls itself with with M_WAITOK even if it was explicitly called with M_NOWAIT set. The bug is real and would cause a panic if we actually ran low on memory at that point. Cheers, -Peter -- Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message