On Wed, 2010-06-16 at 20:54 +0200, Peter Zijlstra wrote: > On Mon, 2010-06-14 at 15:44 +0100, Richard Kennedy wrote: > > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > > > index 2fdda90..315dd04 100644 > > > --- a/mm/page-writeback.c > > > +++ b/mm/page-writeback.c > > > @@ -144,7 +144,7 @@ static int calc_period_shift(void) > > > else > > > dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) / > > > 100; > > > - return 2 + ilog2(dirty_total - 1); > > > + return ilog2(dirty_total - 1) - 4; > > > } > > IIRC I suggested similar things in the past and all we needed to do was > find people doing the measurements on different bits of hardware or so.. > > I don't have any problems with the approach, all we need to make sure is > that we never return 0 or a negative number (possibly ensure a minimum > positive shift value). Yep that sounds reasonable. would minimum shift of 4 be ok ? something like max ( (ilog2(dirty_total - 1)- 4) , 4); Unfortunately volunteers don't seem to be leaping out of the woodwork, maybe Andrew could be persuaded to try this in his tree for a while and see if any one squeaks ? regards Richard -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>