Re: [PATCH V3] KSM: allow dedup all tasks memory

[Timofey Titovets]

ÑÑ, 14 ÐÐÑÐ. 2018 Ð. Ð 01:53, Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>:
>
> > > > That must work, but we out of bit space in vm_flags [1].
> > > > i.e. first 32 bits already defined, and other only accessible only on
> > > > 64-bit machines.
> > >
> > > So, grow vm_flags_t to 64-bit, or enable this feature on 64-bit only.
> >
> > With all due respect to you, for that type of things we need
> > mm maintainer opinion.
>
> As far as I understood, you already got directions from the maintainers
> to do similar to the way THP is implemented, and THP uses two flags:
>
> VM_HUGEPAGE VM_NOHUGEPAGE, the same as I am thinking ksm should do if we
> honor MADV_UNMERGEABLE.
>
> When VM_NOHUGEPAGE is set khugepaged ignores those VMAs.
>
> There may be a way to add VM_UNMERGEABLE without extending the size of
> vm_flags, but that would be a good start point in looking how to add a
> new flag.
>
> Again, you could simply enable this feature on 64-bit only.
>
> Pasha
>

Deal!
I will try with only on 64bit machines.