On Mon, Feb 28, 2011 at 03:52:53PM -0800, Greg Thelen wrote:
> On Sun, Feb 27, 2011 at 8:07 AM, Minchan Kim <minchan.kim@xxxxxxxxx> wrote:
> > On Fri, Feb 25, 2011 at 01:35:54PM -0800, Greg Thelen wrote:
> >> Convert two balance_dirty_pages() page counter variables (nr_reclaimable
> >> and nr_writeback) from 'long' to 'unsigned long'.
> >>
> >> These two variables are used to store results from global_page_state().
> >> global_page_state() returns unsigned long and carefully sums per-cpu
> >> counters explicitly avoiding returning a negative value.
> >>
> >> Signed-off-by: Greg Thelen <gthelen@xxxxxxxxxx>
> > Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> >
> >> ---
> >> Changelog since v4:
> >> - Created this patch for clarity. Previously this patch was integrated within
> >> the "writeback: create dirty_info structure" patch.
> >>
> >> mm/page-writeback.c | 6 ++++--
> >> 1 files changed, 4 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> >> index 2cb01f6..4408e54 100644
> >> --- a/mm/page-writeback.c
> >> +++ b/mm/page-writeback.c
> >> @@ -478,8 +478,10 @@ unsigned long bdi_dirty_limit(struct backing_dev_info *bdi, unsigned long dirty)
> >> static void balance_dirty_pages(struct address_space *mapping,
> >> unsigned long write_chunk)
> >> {
> >> - long nr_reclaimable, bdi_nr_reclaimable;
> >> - long nr_writeback, bdi_nr_writeback;
> >> + unsigned long nr_reclaimable;
> >> + long bdi_nr_reclaimable;
> >> + unsigned long nr_writeback;
> >> + long bdi_nr_writeback;
> >> unsigned long background_thresh;
> >> unsigned long dirty_thresh;
> >> unsigned long bdi_thresh;
> >> --
> >> 1.7.3.1
> >>
> > bdi_nr_[reclaimable|writeback] can return negative value?
> > When I just look through bdi_stat_sum, it uses *percpu_counter_sum_positive*.
> > So I guess it always returns positive value.
> > If it is right, could you change it, too?
>
> Yes, I think we can also change bdi_nr_[reclaimable|writeback] to unsigned long.
>
> bdi_stat_sum() and bdi_stat() both call percpu_counter_sum_positive(),
> which return a positive number. bdi_stat[_sum]() return s64. Should
> we also change bdi_stat[_sum]() to return unsigned long rather than
> s64? I would like the return value type to match the type of the
> corresponding local variables in balance_dirty_pages(). All current
> callers appear to expect bdi_stat[_sum]() to return unsigned long.
Please, clear them, too.
But this patch could be orthogonal with your series so it's up to you. :)
>
> > --
> > Kind regards,
> > Minchan Kim
> >
--
Kind regards,
Minchan Kim
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>