On Fri, Jul 16, 2021 at 07:19:24AM +0200, Michal Hocko wrote: > On Thu 01-07-21 07:54:30, minyard@xxxxxxx wrote: > > From: Corey Minyard <cminyard@xxxxxxxxxx> > > > > If you have a process with less than 1000 totalpages, the calculation: > > > > adj = (long)p->signal->oom_score_adj; > > ... > > adj *= totalpages / 1000; > > > > will always result in adj being zero no matter what oom_score_adj is, > > which could result in the wrong process being picked for killing. > > > > Fix by adding 1000 to totalpages before dividing. > > Yes, this is a known limitation of the oom_score_adj and its scale. > Is this a practical problem to be solved though? I mean 0-1000 pages is > not really that much different from imprecision at a larger scale where > tasks are effectively considered equal. Known limitation? Is this documented? I couldn't find anything that said "oom_score_adj doesn't work at all with programs with <1000 pages besides setting the value to -1000". > > I have to say I do not really like the proposed workaround. It doesn't > really solve the problem yet it adds another special case. The problem is that if you have a small program, there is no way to set it's priority besides completely disablling the OOM killer for it. I don't understand the special case comment. How is this adding a special case? This patch removes a special case. Small programs working different than big programs is a special case. Making them all work the same is removing an element of surprise from someone expecting things to work as documented. -corey
