Subject: Re: What's MMU context?

From: Dan Malek <[email-masked]>
Date: Wed, 27 Oct 1999 11:55:33 -0400

Wang Yong wrote:
> 
> as the source code of linuxPPC, there is a global variable named
> next_mmu_context which is increased by one at each time of create a new
> process. what does this mean and what is mmu context?

I intened to use it on the 8xx processors, as they have an address
space id that allows a TLB optimization so you don't have to
invalidate the entire TLB on context switches.  I assume the
MIPS folks use it as well, since that is where I first used
such an optimization (in an OS other than Linux).  Unfortunately,
the ratio of entries to ASIDs is wrong for my original MIPS-like
algorithm to work, and I never got around to writing something
new.

This was already part of the Linux/PPC port when I started the 8xx
work, and I don't know if other processors use it or if it was
just part of the generic port that was maintained.

	-- Dan

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