Steps to Reproduce
UE 5.6.1(Both code build and launch can repro this problem)
Repro steps:
1.Create a World-Partition-enabled Level, Create a 2K size landscape(Section Size = 255, World Partition Region Size = 4, others default) and enable landscape nanite.Now all LandscapeStreamingProxies are unloaded.
2.Pin parts of LandscapeStreamingProxies(like pin 4 proxies) on Outliner panel to load them, select them and build nanite from button on details panel.
3.Save these pinned LandscapeStreamingProxies.
4.Unpin these LandscapeStreamingProxies to unload them.
5.Repeat step 2,3,4 to build all LandscapeStreamingProxies.
6.Switch to another empty level, execute “Obj GC”.Memory leak about 4~5G(Total RAM go from 6.4G to 11.5G.
I try debug this problem by memory insights. Time A is step 1.Time B is step 6.And I found the BulkData causes the problem.The payload of BulkData of LandscapeNaniteComponent’s UStaticMesh is a SharedBuffer and finally in step 5, its RefCount reamins one, from the FBulkDataRegistryImpl::Registry. When FBulkDataRegistryImpl::OnExitMemory is called, the BulkData of LandscapeNaniteComponent’s UStaticMesh just sets bInMemory to false, and do not release the RAM.It is not memory only payload.If I force execute “Existing→BulkData.Reset()“, it likes fixed.But I do not know its consequence.
I’m rookie in unreal bulk data management.So I’m confused why.When I build nanite for a 16K landscape.This will cause OOM.Please Help~
