Messages in this thread | | | From | Roman Gushchin <> | Subject | Re: [PATCH v2 2/2] mm, oom: remove 'prefer children over parent' heuristic | Date | Wed, 23 Jan 2019 04:41:42 +0000 |
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On Mon, Jan 21, 2019 at 10:50:32AM -0800, Shakeel Butt wrote: > From the start of the git history of Linux, the kernel after selecting > the worst process to be oom-killed, prefer to kill its child (if the > child does not share mm with the parent). Later it was changed to prefer > to kill a child who is worst. If the parent is still the worst then the > parent will be killed. > > This heuristic assumes that the children did less work than their parent > and by killing one of them, the work lost will be less. However this is > very workload dependent. If there is a workload which can benefit from > this heuristic, can use oom_score_adj to prefer children to be killed > before the parent. > > The select_bad_process() has already selected the worst process in the > system/memcg. There is no need to recheck the badness of its children > and hoping to find a worse candidate. That's a lot of unneeded racy > work. Also the heuristic is dangerous because it make fork bomb like > workloads to recover much later because we constantly pick and kill > processes which are not memory hogs. So, let's remove this whole > heuristic.
This is a great cleanup, thanks!
Acked-by: Roman Gushchin <guro@fb.com>
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