Messages in this thread | | | Date | Mon, 27 Nov 2017 19:32:18 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm: disable `vm.max_map_count' sysctl limit |
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On Mon 27-11-17 09:25:16, Andi Kleen wrote: > Michal Hocko <mhocko@kernel.org> writes: > > > > Could you be more explicit about _why_ we need to remove this tunable? > > I am not saying I disagree, the removal simplifies the code but I do not > > really see any justification here. > > It's an arbitrary scaling limit on the how many mappings the process > has. The more memory you have the bigger a problem it is. We've > ran into this problem too on larger systems.
Why cannot you increase the limit?
> The reason the limit was there originally because it allows a DoS > attack against the kernel by filling all unswappable memory up with VMAs.
We can reduce the effect by accounting vmas to memory cgroups. -- Michal Hocko SUSE Labs
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