[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] kswapd performance fix
On Fri, 25 Feb 2000, Stephen C. Tweedie wrote:
> On Fri, 25 Feb 2000 00:30:59 +0100 (CET), Rik van Riel
> <riel@nl.linux.org> said:
>
> > The patch should apply to any 2.2 or 2.3 kernel, but for
> > 2.3 it'll have the interesting side effect of nullifying
> > the (minimal) page aging that's going on there.
>
> Have you actually tested the impact of this under a variety of
> load conditions? In the past we have seen such apparently trivial
> changes completely break the VM balance under certain loads.
The PG_referenced bit isn't used for anything except for
NRU/LRU page reclaiming in shrink_mmap().
However, shrink_mmap() will skip over any pages that are
still mapped by processes _and_ when we unmap the page
from the (next to) last user we set the PG_referenced bit.
The PG_referenced bit is also not used at all by shrink_mmap(),
unless (page->count == 1); shm_swap() doesn't use the referenced
bit at all.
regards,
Rik
--
The Internet is not a network of computers. It is a network
of people. That is its real strength.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux.eu.org/Linux-MM/