Messages in this thread | | | Date | Wed, 4 Apr 2018 09:58:29 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH 1/3] mm: memcontrol: Use cgroup_rstat for event accounting |
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Hello,
On Wed, Apr 04, 2018 at 04:34:47PM +0200, Michal Hocko wrote: > > > The lazy updates are neat, but I'm a little concerned at the memory > > > footprint. On a 64-cpu machine for example, this adds close to 9000 > > > words to struct mem_cgroup. And we really only need the accuracy for > > > the 4 cgroup items in memory.events, not all VM events and stats. > > > > > > Why not restrict the patch to those? It would also get rid of the > > > weird sharing between VM and cgroup enums. > > > > In fact, I wonder if we need per-cpuness for MEMCG_LOW, MEMCG_HIGH > > etc. in the first place. They describe super high-level reclaim and > > OOM events, so they're not nearly as hot as other VM events and > > stats. We could probably just have a per-memcg array of atomics. > > Agreed!
Ah, yeah, if we aren't worried about the update frequency of MEMCG_HIGH, which likely is the highest freq, we can just switch to atomic_t. I'm gonna apply the cgroup stat refactoring patches to cgroup, so if we ever wanna switch the counter to rstat, we can easily do that later.
Thasnks.
-- tejun
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