also sprach Anthony DeRobertis <asd@suespammers.org> [2002.09.26.1322 +0200]:
> > i am repeatedly seeing the term "page fault" being used in Debian in
> > the wrong way.
>
> (examples?)
libsigsegv-dev's description
various posts to the debian-* lists
> It has quite a bit to do with an invalid access. As far as the MMU is
> concerned, it *is* an invalid access: There is no page mapped to the
> address, and thus it throws a (hardware) exception called a 'page
> fault'.
Right. I was trying not to go into too much detail. A fault is an
exception, something that's not expected. These days, page faults are
rather expected to happen.
> > A page fault simply occurs
> > when a memory access causes the memory management system to have to
> > fetch the requested page from swap.
>
> Not quite. Page faults can be satisfied from things besides disk as
> well. Example: bringing in part of an ELF fragment from the page cache.
> Example: first write to newly allocated (in the kernel's view) memory.
> Example: High-mem support.
Okay, okay.
> Even things like copy-on-write pages (from, e.g., fork) generate
> something that might be called a page fault on the first write attempt.
> So does an attempt to write to null.
Alright, I have simplified it too much.
--
martin; (greetings from the heart of the sun.)
\____ echo mailto: !#^."<*>"|tr "<*> mailto:"; net@madduck
"all unser übel kommt daher,
daß wir nicht allein sein können."
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