On Mon, Aug 28, 2017 at 08:45:07AM +0200, Vlastimil Babka wrote: > +CC linux-api > > On 08/28/2017 02:28 AM, Joonsoo Kim wrote: > > On Fri, Aug 25, 2017 at 09:56:10AM +0200, Vlastimil Babka wrote: > >> On 08/25/2017 02:20 AM, Joonsoo Kim wrote: > >>> On Thu, Aug 24, 2017 at 11:41:58AM +0200, Vlastimil Babka wrote: > >>> > >>> Hmm, this is already pointed by Minchan and I have answered that. > >>> > >>> lkml.kernel.org/r/<20170421013243.GA13966@js1304-desktop> > >>> > >>> If you have a better idea, please let me know. > >> > >> My idea is that size of sysctl_lowmem_reserve_ratio is ZONE_NORMAL+1 and > >> it has no entries for zones > NORMAL. The > >> setup_per_zone_lowmem_reserve() is adjusted to only set > >> lower_zone->lowmem_reserve[j] for idx <= ZONE_NORMAL. > >> > >> I can't imagine somebody would want override the ratio for HIGHMEM or > >> MOVABLE > >> (where it has no effect anyway) so the simplest thing is not to expose > >> it at all. > > > > Seems reasonable. However, if there is a user who checks > > sysctl_lowmem_reserve_ratio entry for HIGHMEM and change it, suggested > > interface will cause a problem since it doesn't expose ratio for > > HIGHMEM. Am I missing something? > > As you explained, it makes little sense to change it for HIGHMEM which > only affects MOVABLE allocations. Also I doubt there are many systems > with both HIGHMEM (implies 32bit) *and* MOVABLE (implies NUMA, memory > hotplug...) zones. So I would just remove it, and if somebody will > really miss it, we can always add it back. In any case, please CC > linux-api on the next version. If we will accept a change that potentially breaks the user, I think that making zero as a special value for sysctl_lowmem_reserve_ratio is better solution. How about this way? Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
