Low memory handling?

[mogmios]

In .NET or C# is there any standard cross-platform way to receive a low memory notice before actually running out of memory? With Xamarin you can use DidReceiveMemoryWarning and there seems to be a couple methods specific to Windows that appear to throw mystery errors when I try to use them.

I thought there might be some sort of event I could listen for but I'm not finding one. Simply marking fields with some sort of LowMemoryAction attribute seemed a possibility also but didn't find anything like that either.

For example, I have an object that computes an expensive operation for a FileSystemInfo object and which will run recursively to children if it represents a directory. I cache the result of the operation to speed up repeated calls but the operation can be redone without problem if need be. I'd like to be able to clear this cache if memory gets low. Currently using MemoryCache but it's not a very good solution.

A standard way to handle this and other system events seems important as .NET appears to be moving towards being much more cross-platform friendly.

[iam3yal]

This is the Roslyn repo aka ".NET Compiler Platform" and what you're asking is kinda irrelevant to this repo, however, you can try this repo CoreFx or even this CoreCLR.

I don't know why Xamarin throws, well you probably refer to Mono not Xamarin but on Windows there's a low-level API called CreateMemoryResourceNotification, you can try that.

[mogmios]

Ok, I'll look at those places. And will look at CreateMemoryResourceNotification.

Just for completeness, it was MemoryManager AppMemoryUsageDecreased and most of the related functionality that would compile ok but then throw errors at runtime that didn't seem to make any sense. Happened when registering any of the events and with most method calls.

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Issue Details

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In .NET or C# is there any standard cross-platform way to receive a low memory notice before actually running out of memory? With Xamarin you can use DidReceiveMemoryWarning and there seems to be a couple methods specific to Windows that appear to throw mystery errors when I try to use them. I thought there might be some sort of event I could listen for but I'm not finding one. Simply marking fields with some sort of LowMemoryAction attribute seemed a possibility also but didn't find anything like that either. For example, I have an object that computes an expensive operation for a FileSystemInfo object and which will run recursively to children if it represents a directory. I cache the result of the operation to speed up repeated calls but the operation can be redone without problem if need be. I'd like to be able to clear this cache if memory gets low. Currently using MemoryCache but it's not a very good solution. A standard way to handle this and other system events seems important as .NET appears to be moving towards being much more cross-platform friendly.

Author:	mogmios
Assignees:	-
Labels:	`question`, `area-GC-coreclr`, `untriaged`
Milestone:	-

[mangod9]

@cshung