On Tue, 9 Nov 2010, KOSAKI Motohiro wrote: > > > > The new tunable added in 2.6.36, /proc/pid/oom_score_adj, is necessary for > > > > the units that the badness score now uses. We need a tunable with a much > > > > > > Who we? > > > > > > > Linux users who care about prioritizing tasks for oom kill with a tunable > > that (1) has a unit, (2) has a higher resolution, and (3) is linear and > > not exponential. > > No. Majority user don't care. You only talk about your case. Don't ignore > end user. > If they don't care, then they won't be using oom_adj, so you're point about it's deprecation is irrelevant. Other users do want a more powerful userspace interface with a unit and higher resolution (I am one of them), there's no requirement that those users need to be in the majority. > > Memcg doesn't solve this issue without incurring a 1% > > memory cost. > > Look at a real. > All major distributions has already turn on memcg. End user don't need > to pay additional cost. > Memcg also has a command-line disabling option to avoid incurring this 1% memory cost when you're not going to be using it. > > No, it doesn't, and you completely and utterly failed to show a single > > usecase that broke as a result of this because nobody can currently use > > oom_adj for anything other than polarization. Thus, there's no backwards > > compatibility issue. > > No. I showed. > 1) Google code search showed some application are using this feature. > http://www.google.com/codesearch?as_q=oom_adj&btnG=Search+Code&hl=ja&as_package=&as_lang=&as_filename=&as_class=&as_function=&as_license=&as_case= > oom_adj isn't removed, it's deprecated. These users are using a deprecated interface and have a few years to convert to using the new interface (if it ever is actually removed). > 2) Not body use oom_adj other than polarization even though there are a few. > example, kde are using. > http://www.google.com/codesearch/p?hl=ja#MPJuLvSvNYM/pub/kde/unstable/snapshots/kdelibs.tar.bz2%7CWClmGVN5niU/kdelibs-1164923/kinit/start_kdeinit.c&q=oom_adj%20kde%205 > > When you are talking polarization issue, you blind a real. Don't talk your dream. > I don't understand what you're trying to say here, but the current users of oom_adj that aren't +15 or -16 (or OOM_DISABLE) are arbitrary based relative to other tasks such as +5, +10, etc. They don't have any semantics other than being arbitrarily relative because it doesn't work in a linear way or with a scale. > 3) udev are using this feature. It's one of major linux component and you broke. > > http://www.google.com/codesearch/p?hl=ja#KVTjzuVpblQ/pub/linux/utils/kernel/hotplug/udev-072.tar.bz2%7CwUSE-Ay3lLI/udev-072/udevd.c&q=oom_adj > > You don't have to break our userland. you can't rewrite or deprecate > old one. It's used! You can only add orthogonal new knob. > That's incorrect, I didn't break anything by deprecating a tunable for a few years. oom_adj gets converted roughly into an equivalent (but linear) oom_score_adj. Unfortunately for your argument, you can't show a single example of a current oom_adj user that has a scientific calculation behind its value that is now broken on the linear scale. > > Yes, I've tested it, and it deprecates the tunable as expected. A single > > warning message serves the purpose well: let users know one time without > > being overly verbose that the tunable is deprecated and give them > > sufficient time (2 years) to start using the new tunable. That's how > > deprecation is done. > > no sense. > > Why do their application need to rewrite for *YOU*? Okey, you will got > benefit from your new knob. But NOBDOY use the new one. and People need > to rewrite their application even though no benefit. > > Don't do selfish userland breakage! > It's deprecated for a few years so users can gradually convert to the new tunable, it wasn't removed when the new one was introduced. A higher resolution tunable that scales linearly with a unit is an advantage for Linux (for the minority of users who care about oom killing priority beyond the heuristic) and I think a few years is enough time for users to do a simple conversion to the new tunable. -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>