On Sun, 8 Oct 2000, Linus Torvalds wrote:
> On Wed, 4 Oct 2000, Rik van Riel wrote:
> >
> > The potential for this bug has been around since 2.3.51, when
> > different balance_ratios for different zones became possible.
> You must NOT depend on some global "freepages" thing.
> Don't do this patch. Fix it for real instead. You can use the
> global amount of free memory for heuristics, but you MUST NOT
> use it for deciding to not page stuff out etc - because you will
> _always_ end up with cases where you decide that you globally
> have enough memory even though locally there is a memory
> shortage (or the other way around - you end up thinking that
> there is a global memory shortage even if all local memories are
> plenty fine, so you end up trying to swap stuff out when it
> shouldn't be done).
Please read mm/vmscan.c::free_shortage()
The code honours /both/ global and local shortages.
(but indeed, we shouldn't - and in retrospect don't - depend
on global values and can make /proc/sys/vm/freepages writable
again so the sysadmin can give a balancing hint on how many
free pages to keep around ... which may be important for folks
doing gigabit routing)
regards,
Rik
--
"What you're running that piece of shit Gnome?!?!"
-- Miguel de Icaza, UKUUG 2000
http://www.conectiva.com/ http://www.surriel.com/
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