Re: [RFC][PATCH -mm 1/2] mm: make shrink_all_memory overflow-resistant

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday 28 February 2006 04:16, Andrew Morton wrote:
> "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
> >
> > Make shrink_all_memory() overflow-resistant.
> > 
> 
> As you've probably noticed, I'm moving toward making all the scalars which
> hold counts of pages in the VM toward unsigned long.  For uniformity, and
> because there is a small risk that a huge machine with 4k pages could
> actually overflow a 32-bit counter.
> 
> > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> > ---
> >  include/linux/swap.h |    2 +-
> >  mm/vmscan.c          |    9 +++++----
> >  2 files changed, 6 insertions(+), 5 deletions(-)
> > 
> > Index: linux-2.6.16-rc4-mm2/mm/vmscan.c
> > ===================================================================
> > --- linux-2.6.16-rc4-mm2.orig/mm/vmscan.c
> > +++ linux-2.6.16-rc4-mm2/mm/vmscan.c
> > @@ -1785,18 +1785,19 @@ void wakeup_kswapd(struct zone *zone, in
> >   * Try to free `nr_pages' of memory, system-wide.  Returns the number of freed
> >   * pages.
> >   */
> > -int shrink_all_memory(unsigned long nr_pages)
> > +unsigned long shrink_all_memory(unsigned int nr_pages)
> 
> So nr_pages should remain unsigned long.
> 
> > +	long long nr_to_free = nr_pages;
> 
> As should nr_to_free.

OK

> The actual bug is the (unsigned <= 0) thing.   So how's about this?

I like it (if my opinion matters here ;-)).  Thanks a lot.