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Date: Sat, 10 May 2003 12:13:52 -0700
From: David Schultz <das@FreeBSD.ORG>
To: Terry Lambert <tlambert2@mindspring.com>
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cc: arch@FreeBSD.ORG
cc: John Baldwin <jhb@FreeBSD.ORG>
Subject: Re: [Bikeshed] sigacts locking
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On Sat, May 10, 2003, Terry Lambert wrote:
> David Schultz wrote:
> > It occurs to me that this leaves very little in the uarea.  You
> > have a struct pstats, which is less than 256 bytes, and you have
> > the kinfo_proc, which shouldn't need to be there anyway.  Perhaps
> > now would also be a good time to get rid of uarea swapping and the
> > associated complexity altogether.
> 
> The swapping of the uarea doesn't really introduce a lot of
> extra complexity, since all it does is allocate swappable
> pages, just like the swappable pages in user space.
> 
> Change that mode stuff out of the uarea are probably a bad
> idea, since it increases KVA pressure by moving them to
> wired kernel pages.

No, they're already wired kernel pages that are unwired and
unmapped when the process is swapped out.  Moreover, there's
probably *more* KVA pressure with upages swapping, because each
tiny struct upages gets a 4K or larger page all to itself unless
it's swapped out.