Messages in this thread | | | Date | Tue, 7 Sep 2021 12:42:01 -0700 | From | Roman Gushchin <> | Subject | Re: [memcg] 0f12156dff: will-it-scale.per_process_ops -33.6% regression |
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On Tue, Sep 07, 2021 at 10:48:06AM -0700, Shakeel Butt wrote: > On Tue, Sep 7, 2021 at 10:31 AM Roman Gushchin <guro@fb.com> wrote: > > > > On Tue, Sep 07, 2021 at 07:14:45AM -1000, Tejun Heo wrote: > > > Hello, > > > > > > On Tue, Sep 07, 2021 at 10:11:21AM -0700, Roman Gushchin wrote: > > > > There are two polar cases: > > > > 1) a big number of relatively short-living allocations, which lifetime is well > > > > bounded (e.g. by a lifetime of a task), > > > > 2) a relatively small number of long-living allocations, which lifetime > > > > is potentially indefinite (e.g. struct mount). > > > > > > > > We can't use the same approach for both cases, otherwise we'll run into either > > > > performance or garbage collection problems (which also lead to performance > > > > problems, but delayed). > > > > > > Wouldn't a front cache which expires after some seconds catch both cases? > > > > I'm not sure. For the second case we need to pack allocations from different > > tasks/cgroups into a small number of shared pages. It means the front cache > > should be really small/non-existing. For the first case we likely need a > > substantial cache. Maybe we can do something really smart with scattering > > the cache over multiple pages, but I really doubt. > > I think we need to prototype this to sensibly evaluate. Let me know if > you want to take a stab at this otherwise I can try.
If you have time and are ready to jump in, please, go on. Otherwise I can start working on it in few weeks. In any case, I'm happy to help with discussions, code reviews & whatever else I can do.
Thanks!
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