Messages in this thread | | | Date | Fri, 15 Sep 2006 11:21:39 +0400 | From | Pavel Emelianov <> | Subject | Re: [ckrm-tech] [PATCH] BC: resource beancounters (v4) (added user memory) |
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Chandra Seetharaman wrote: > On Thu, 2006-09-14 at 17:02 +0400, Pavel Emelianov wrote: > > <snip> > >> Reserving in advance means that sometimes you won't be able to start a >> new group without taking back some of reserved pages. This is ... strange. >> > > I do not see it strange. At the time of creation, user sees the failure > (that there isn't enough resource to provide the required/requested > guarantee) and can act accordingly. > > BTW, VMware does it this way. > And VPS density in VMware is MUCH lower than in OpenVZ with beancounters :) > >> I think that a satisfactory solution now would be: >> - limit unreclaimable memory during mmap() against soft limit to prevent >> potential rejects during page faults; >> > > we can have guarantee and still handle it this way. > >> - reclaim memory in case of hitting hard limit; >> - guarantees are done via setting soft and hard limits as I've shown >> before. >> > > complexity is high in doing that. > Nope. I've already said in another letter that a program of 60 lines does this in a single loop. >> The question still open is wether or not to account fractions. >> I propose to skip fractions for a while and try to charge the page to >> it's first user. >> > > sounds fine > > >> So final BC design is: >> 1. three resources: >> - kernel memory >> - user unreclaimable memory >> - user reclaimable memory >> > > should be able to get other controllers also under this framework. > OK. But note, that it's easy to add new resource to current BC code. The most difficult thing is placing 'charge/uncharge' calls over the kernel. > >> 2. unreclaimable memory is charged "in advance", reclaimable >> is charged "on demand" with reclamation if needed >> 3. each object (kernel one or user page) is charged to the >> first user >> 4. each resource controller declares it's own >> - meaning of "limit" parameter (percent/size/bandwidth/etc) >> - behaviour on changing limit (e.g. reclamation) >> - behaviour on hitting the limit (e.g. reclamation) >> 5. BC can be assigned to any task by pid (not just current) >> without recharging currently charged resources. >> > > Please see the emails i sent earlier in this context: > http://marc.theaimsgroup.com/?l=ckrm-tech&m=115593001810616&w=2 > > We would need at least: > - BC should be created/deleted explicitly by the user > - cleaner interface for controller writers > OK. Next week we'll try to send a new set of patches. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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