On Tue 04-09-12 18:37:53, Glauber Costa wrote: > On 09/04/2012 06:35 PM, Michal Hocko wrote: > > On Tue 04-09-12 17:27:20, Glauber Costa wrote: > >> On 09/04/2012 05:09 PM, Michal Hocko wrote: > >>> Not really. Do it slowly means that somebody actually _notices_ that > >>> something is about to change and they have a lot of time for that. This > >>> will be really hard with the config option saying N by default. People > >>> will ignore that until it's too late. > >>> We are interested in those users who would keep the config default N and > >>> they are (ab)using use_hierarchy=0 in a way which is hard/impossible to > >>> fix. This is where distributions might help and they should IMHO but why > >>> to put an additional code into upstream? Isn't it sufficient that those > >>> who would like to help (and take the risk) would just take the patch? > >> > >> At least Fedora, seem to frown upon heavily at non-upstream patches. > > > > OK, so what about the following approach instead? We won't change the > > default but rather shout at people when they actually create subtrees > > with use_hierarchy==0. This shouldn't make pointless noise. I do not > > remember whether we have considered this previously so sorry if this was > > shot down as well. > > The warning is fine, but just shouting won't achieve nothing. I am not so sure about that. Users are usually quite sensitive to WARN messages and I can put this kind of patch into older code bases as well because it cannot introduce any regression. This could produce a much bigger testing base. All we want to achieve at this stage is to find out whether we can get rid of the knob and help people to use use_hierarchy=1, right? > I believe it would be really great to have a way to turn the default > to 1 - and stop the shouting. We already can. You can use /etc/cgconfig (if you are using libcgroup) or do it manually. > Even if you are doing it in OpenSUSE as a patch, an upstream patch means > at least that every distribution is using the same patch, and those who > rebase will just flip the config. > > I'd personally believe merging both our patches together would achieve a > good result. I am still not sure we want to add a config option for something that is meant to go away. But let's see what others think. -- Michal Hocko 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>