On Mon, Dec 04, 2023 at 11:33:12AM +0100, Michal Hocko wrote: > On Fri 01-12-23 16:25:06, Kent Overstreet wrote: > > On Fri, Dec 01, 2023 at 11:04:23AM +0100, Michal Hocko wrote: > > > On Thu 30-11-23 20:47:45, Kent Overstreet wrote: > > > > On Thu, Nov 30, 2023 at 09:14:35AM +0100, Michal Hocko wrote: > > > [...] > > > > > All that being said, I am with you on the fact that the oom report in > > > > > its current form could see improvements. > > > > > > > > I'm glad we're finally in agreement on something! > > > > > > > > If you want to share your own ideas on what could be improved and what > > > > you find useful, maybe we could find some more common ground. > > > > > > One thing that I would consider an improvement is to have a way to > > > subscribe drivers with excessive memory consumption or those which are > > > struggling to dump their state. > > > > Remember the memory allocation profiling patchset? The one where you > > kept complaining about "maintenancy overhead"? > > Yes, I still maintain my opinion on that approach. I have never > questioned usefulness of the information. > > > We can plug that into the show_mem report too, and list the top 10 > > allocations by file and line number. > > > > > Maybe your proposal can be extended that way but the crucial point is to > > > not dump all sorts of random shrinkers' state and end up with unwieldy > > > reports. If, on the other hand, any particular shrinker struggles to > > > reclaim memory and it is sitting on a lot of memory it could be able to > > > flag itself to be involved in the dump. > > > > Great, since as was mentioned in the original commit message it's not > > "all sorts of random shrinkers", but top 10 by objects reported, what > > I've got here should make you happy. > > Can we do better and make that a shrinker decision rather than an > arbitrary top N selection? The thing is that shrinkers might even not > matter in many cases so their output would be just a balast. The number > of objects is not universaly great choice. As Dave mentioned metdata > might be pinning other objects. > > That being said, if you want to give more debugability power to > shrinkers then it makes more sense to allow them to opt-in for the oom > report rather than control which of them to involve from the oom > reporting code which doesn't have enough context on its own. If you've got an idea for a refinement, please submit your own patch and I'll look at incorporating it into the series.
