Re: [2.4.17/18pre] VM and swap - it's really unusable

yodaiken
2002-01-12T19:26:09Z

On Sat, Jan 12, 2002 at 06:48:28PM +0100, Roman Zippel wrote:
> Hi,
>
> yodaiken@fsmlabs.com wrote:
>
> > No. The point of using semaphores is that one can sleep while
> > _waiting_ for the resource.
> > [...]
> > In a preemptive kernel this can cause a deadlock. In a non
> > preemptive it cannot. You are correct in that
> > B:
> > get sem on memory pool
> > do potentially blocking operations
> > release sem
> > is also dangerous - but I don't think that helps your case.
> > To fix B, we can enforce a coding rule - one of the reasons why
> > we have all those atomic ops in the kernel is to be able to
> > avoid this problem.
>
> Sorry I can't follow you. First, one can sleep while waiting for the

We're having a write only discussion - time to stop.