On Fri, 16 Jul 2021 07:25:47 -0500 Corey Minyard <cminyard@xxxxxxxxxx> wrote: > 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. > Can we please get this resolved one way or the other?
