On Tue, Dec 10, 2013 at 01:44:35AM -0500, Naoya Horiguchi wrote: > Hi Wanpeng, > > On Sun, Dec 08, 2013 at 02:14:50PM +0800, Wanpeng Li wrote: > > commit 04bb2f947 (sched/numa: Adjust scan rate in task_numa_placement) > > calculate > > period_slot which should be used as base value of scan rate increase if > > remote > > access dominate. However, current codes forget to use it, this patch fix it. > > > > Signed-off-by: Wanpeng Li <liw...@linux.vnet.ibm.com> > > --- > > kernel/sched/fair.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 7073c76..b077f1b3 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -1358,7 +1358,7 @@ static void update_task_scan_period(struct > > task_struct *p, > > */ > > period_slot = DIV_ROUND_UP(diff, NUMA_PERIOD_SLOTS); > > ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + > > shared)); > > - diff = (diff * ratio) / NUMA_PERIOD_SLOTS; > > + diff = (period_slot * ratio) / NUMA_PERIOD_SLOTS; > > } > > > > p->numa_scan_period = clamp(p->numa_scan_period + diff, > > It seems to me that the original code is correct, because the mathematical > meaning of this hunk is clear: > > diff = (diff calculated by local-remote ratio) * (private-shared ratio) >
Thanks Naoya. The original code is as intended and was meant to scale the difference between the NUMA_PERIOD_THRESHOLD and local/remote ratio when adjusting the scan period. The period_slot recalculation can be dropped. -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
