Limit memory pool size

[JanEggers]

Hello we run our app inside a container that is limited to 20 GB. we recently hit this limit so I pulled a dump at 5 GB to see where memory is going.

to me it looks like most of the memory goes to byte arrays allocated by kestrel. is there any way to limit the amount of memory that is allocated / pooled by the shared pool?

[martincostello]

Looks related to (or even a duplicate of) #55490.

[BrennanConroy]

Yep, duplicate of the issue Martin linked. While we are planning on releasing pooled memory from the pool starting in .NET 10, the real issue is your app is taking on too much load and/or is writing responses inefficiently.

e.g. if you did something like httpContext.Body.WriteAsync(new byte[10_000_000]) that would be much worse than if you wrote it in smaller chunks.

For the too much load part, you would want to look at rate limiting or distributing the load between multiple servers.

[JanEggers]

we just return sometimes large json but we never write responses directly that is all handled by asp.net / system.text.json.

unfortunatly we use inmemory state so we have to do a little cleanup before we are able to scale out.

are there any apis I can tap into to figure out which code is allocating the large chunks?

[BrennanConroy]

https://learn.microsoft.com/en-us/dotnet/core/diagnostics/dotnet-trace#dotnet-trace-collect
dotnet trace collect --profile gc-verbose -p <process id>