On Tue, Dec 10, 2013 at 08:27:59AM +0000, Mel Gorman wrote: >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 <liwanp@xxxxxxxxxxxxxxxxxx> >> > --- >> > 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. > Thanks Mel's pointing out. ;-) Regards, Wanpeng Li >-- >Mel Gorman >SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>