Re: MOL-MMU (WAS: Power Management)

[Samuel Rydh <samuel@ibrium.se>]

>
>Thanks; I still see a potential problem with MMU context allocation here:
>Paul's new code uses a bitmap to keep track of contexts in use
>(context_map). MOL ignores this bit and just keeps allocating contexts by
>relying on next_mmu_context to be unused (which it should be, most
>of the time), plus the next one also being unused. Is that always
>guaranteed? 

The MOL developer tree contains the necessary fixes:

	(BitKeeper) bk://zorn.theophys.kth.se:5000, 
	(rsync)     zorn.theophys.kth.se::mol

Basically, MOL uses a different range of context than the
kernel (due to the context bitmap, only 32.000 contexts are
used by the kernel so a lot of the contexts are free for MOL).

>And what's the penalty on using a context ID that's already in use?
That would be very bad. From experience, the symptom is a lot
of segfaults (but the kernel could go down too).

/Samuel


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