On Mon, Feb 6, 2023 at 1:14 PM Tejun Heo <tj@xxxxxxxxxx> wrote: > > On Mon, Feb 06, 2023 at 06:47:51PM +1100, Alistair Popple wrote: > > If too much memory in a system is pinned or locked it can lead to > > problems such as performance degradation or in the worst case > > out-of-memory errors as such memory cannot be moved or paged out. > > > > In order to prevent users without CAP_IPC_LOCK from causing these > > issues the amount of memory that can be pinned is typically limited by > > RLIMIT_MEMLOCK. However this is inflexible as limits can't be shared > > between tasks and the enforcement of these limits is inconsistent > > between in-kernel users of pinned memory such as mlock() and device > > drivers which may also pin pages with pin_user_pages(). > > > > To allow for a single limit to be set introduce a cgroup controller > > which can be used to limit the number of pages being pinned by all > > tasks in the cgroup. > > As I wrote before, I think this might fit better as a part of memcg than as > its own controller. 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. > > Thanks. > > -- > tejun
