Messages in this thread |  | | Date | Mon, 18 Nov 2013 17:22:16 -0800 (PST) | From | David Rientjes <> | Subject | Re: [patch 1/2] mm, memcg: avoid oom notification when current needs access to memory reserves |
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On Mon, 18 Nov 2013, Michal Hocko wrote:
> > Even though the situation may not require a kill, the user still wants > > to know that the memory hard limit was breached and the isolation > > broken in order to prevent a kill. We just came really close and the > > You can observe that you are getting into troubles from fail counter > already. The usability without more reclaim statistics is a bit > questionable but you get a rough impression that something is wrong at > least. >
Agreed, but it seems like the appropriate mechanism for this is through the memory.{,memsw.}usage_in_bytes notifiers which already exist.
> > fact that current is exiting is coincidental. Not everybody is having > > OOM situations on a frequent basis and they might want to know when > > they are redlining the system and that the same workload might blow up > > the next time it's run. > > I am just concerned that signaling temporal OOM conditions which do not > require any OOM killer action (user or kernel space) might be confusing. > Userspace would have harder times to tell whether any action is required > or not. >
Completely agreed, in fact there is no reliable and non-racy way in userspace to determine "is this a real oom condition that I must act upon or can the kernel handle it?"
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