"David Schwartz" <davids@webmaster.com>:
> > One would assume the kernel always maintains at least 1
> > page for its own
> > paging purposes. So I touch my swapped out page. The kernel
> > reads my page into
> > the 'last page', and immediately pages out some other page,
> > regaining its "last
> > page". Repeat as necessary. It's a memory thrashing situation,
> > but not fatal.
>
> Fine, until some process touches a COW page and then the one spare page is
> gone. Just because you reserved the space for COW doesn't mean that
> something else won't come along and grab the space you reserved before you
> get a chance to. If you earmark swap pages for COW and don't let anything
> else touch them, you'll have to kill processes when the kernel needs another
> page even if there's plenty of free swap left. That doesn't seem to make a
> lot of sense.
Pay attention -
1. the system is not over committed.
2. all pages allocated are swappable.
3. Only one reserved page is required to exchange any two pages between
swap and real memory.
4. This is the last resort thrash condition.
5. This is not fatal.
-------------------------------------------------------------------------
Jesse I Pollard, II
Email: pollard@navo.hpc.mil
Any opinions expressed are solely my own.
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This archive was generated by hypermail 2b29 : Fri Mar 31 2000 - 21:00:29 EST