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

Luigi Genoni
2002-01-08T23:26:49Z

On Tue, 8 Jan 2002, Daniel Phillips wrote:

> On January 8, 2002 08:47 pm, Andrew Morton wrote:
> > Daniel Phillips wrote:
> > > What a preemptible kernel can do that a non-preemptible kernel can't is:
> > > reschedule exactly as often as necessary, instead of having lots of extra
> > > schedule points inserted all over the place, firing when *they* think the
> > > time is right, which may well be earlier than necessary.
> >
> > Nope. `if (current->need_resched)' -> the time is right (beyond right,
> > actually).
>
> Oops, sorry, right.
>
> The preemptible kernel can reschedule, on average, sooner than the
> scheduling-point kernel, which has to wait for a scheduling point to roll
> around.
>
mmhhh. At which cost? And then anyway if I have a spinlock, I still have
to wait for a scheduling point to roll around.