Messages in this thread | | | Date | Mon, 6 Feb 2023 20:00:54 -0500 | Subject | Re: [PATCH 14/19] mm: Introduce a cgroup for pinned memory | From | Waiman Long <> |
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On 2/6/23 17:39, Yosry Ahmed wrote: > On Mon, Feb 6, 2023 at 2:36 PM Tejun Heo <tj@kernel.org> wrote: >> On Mon, Feb 06, 2023 at 02:32:10PM -0800, Yosry Ahmed wrote: >>> I guess it boils down to which we want: >>> (a) Limit the amount of memory processes in a cgroup can be pinned/locked. >>> (b) Limit the amount of memory charged to a cgroup that can be pinned/locked. >>> >>> The proposal is doing (a), I suppose if this was part of memcg it >>> would be (b), right? >>> >>> I am not saying it should be one or the other, I am just making sure >>> my understanding is clear. >> I don't quite understand what the distinction would mean in practice. It's >> just odd to put locked memory in a separate controller from interface POV. > Assume we have 2 cgroups, A and B. A process in cgroup A creates a > tmpfs file and writes to it, so the memory is now charged to cgroup A. > Now imagine a process in cgroup B tries to lock this memory. > - With (a) the amount of locked memory will count toward's cgroup A's > limit, because cgroup A is charged for the memory. > - With (b) the amount of locked memory will count toward's cgroup B's > limit, because a process in cgroup B is locking the memory. > > I agree that it is confusing from an interface POV.
If it should not be part of the memcg, does it make sense to make it a resource in the existing misc controller? I believe we don't want a proliferation of new cgroup controllers.
Cheers, Longman
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