Re: Question about swap_in() in 2.2.16 ....

["Stephen C. Tweedie" <sct@redhat.com>]

Hi,

On Thu, Nov 09, 2000 at 11:23:05PM -0500, Shuvabrata Ganguly wrote:
> "Stephen C. Tweedie" wrote:
> > > Now this creates a read-only mapping  even if the access was a "write
> > > acess"  ( if the page is shared ). Doesnt this mean that an additional
> > > "write-protect" fault will be taken immediately when the process tries
> > > to write again ?
> >
> > Yes.
> 
> Then why dont we give it a private page in the first place ?

Normal copy-on-write is an extremely performance-critical code path.
It's really not worth the trouble of adding extra code to it to make
the swapin page fault do the same copy-on-write immediately, because
swapin simply is not that important for performance.

--Stephen
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