Messages in this thread | | | Date | Tue, 3 Jul 2018 12:25:17 -0700 | From | Matthew Wilcox <> | Subject | Re: [PATCH v8 03/17] mm: Assign id to every memcg-aware shrinker |
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On Tue, Jul 03, 2018 at 12:19:35PM -0700, Shakeel Butt wrote: > On Tue, Jul 3, 2018 at 12:13 PM Kirill Tkhai <ktkhai@virtuozzo.com> wrote: > > > Do we really have so very many !memcg-aware shrinkers? > > > > > > $ git grep -w register_shrinker |wc > > > 32 119 2221 > > > $ git grep -w register_shrinker_prepared |wc > > > 4 13 268 > > > (that's an overstatement; one of those is the declaration, one the definition, > > > and one an internal call, so we actually only have one caller of _prepared). > > > > > > So it looks to me like your average system has one shrinker per > > > filesystem, one per graphics card, one per raid5 device, and a few > > > miscellaneous. I'd be shocked if anybody had more than 100 shrinkers > > > registered on their laptop. > > > > > > I think we should err on the side of simiplicity and just have one IDR for > > > every shrinker instead of playing games to solve a theoretical problem. > > > > It just a standard situation for the systems with many containers. Every mount > > introduce a new shrinker to the system, so it's easy to see a system with > > 100 or ever 1000 shrinkers. AFAIR, Shakeel said he also has the similar > > configurations. > > > > I can say on our production systems, a couple thousand shrinkers is normal.
But how many are !memcg aware? It sounds to me like almost all of the shrinkers come through the sget_userns() caller, so the other shrinkers are almost irrelevant.
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