C#•3mo ago

FileSystemWatcher causes user limit exceptions on Kubuntu Linux

Using the following code results in the exception

The configured user limit (128) on the number of inotify instances has been reached, or the per-process limit on the number of open file descriptors has been reached.

public static void Init(string ProjectPath, List <ProjectFile> ProjectFileList, List <ProjectDirectory> ProjectDirList, List <Icon> IconList)
{
    ProjectFiles = ProjectFileList;
    ProjectDirs = ProjectDirList;
    Icons = IconList;

    FSWatcher.BeginInit();
    FindItemsInProjectDirectory(null, null);

    FSWatcher.IncludeSubdirectories = true;
    FSWatcher.EnableRaisingEvents = true;
    FSWatcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
    FSWatcher.Changed += new FileSystemEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Created += new FileSystemEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Deleted += new FileSystemEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Renamed += new RenamedEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Path = ProjectPath;
    FSWatcher.EndInit();
}

public static void Init(string ProjectPath, List <ProjectFile> ProjectFileList, List <ProjectDirectory> ProjectDirList, List <Icon> IconList)
{
    ProjectFiles = ProjectFileList;
    ProjectDirs = ProjectDirList;
    Icons = IconList;

    FSWatcher.BeginInit();
    FindItemsInProjectDirectory(null, null);

    FSWatcher.IncludeSubdirectories = true;
    FSWatcher.EnableRaisingEvents = true;
    FSWatcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName | NotifyFilters.DirectoryName;
    FSWatcher.Changed += new FileSystemEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Created += new FileSystemEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Deleted += new FileSystemEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Renamed += new RenamedEventHandler(FindItemsInProjectDirectory);
    FSWatcher.Path = ProjectPath;
    FSWatcher.EndInit();
}

FindItemsInProjectDirectory does not do anything with the fs watcher object.

17 Replies

MazranelOP•3mo ago

I read that I could modify this limit, but that's just a workaround instead of a real solution. It also doesn't work well for portable applications.

Petris•3mo ago

it's either that or having a background thread that call Directory.EnumerateFiles in a loop

MazranelOP•3mo ago

But doesn't it already run on a separate thread?

Omnissiah•3mo ago

what gave you this impression?

MazranelOP•3mo ago

The application runs without any delays or freezing, even with a large amount of files. That's flawed though now that I think about it

wasabi•3mo ago

The issue is INcludeSubdiretories, probably. It's been awhile since I looked, but from what I remember it opens a new inotify channel for each watched directory. And Linux limits those.

MazranelOP•3mo ago

Ah. There really aren't thatany subdirectories though, is there a way to work around this?

wasabi•3mo ago

Nope. Gotta increase the per-user limit. Actually, looking at your error, it's not erroring because of max watches, but because of max instances. Might be the case you're creating too many FSWs

MazranelOP•3mo ago

I should only be creating one, I'll add a console.writeline in the fs watcher init function Yeah it's only creating one instance as far as I'm aware

Petris•3mo ago

for context, the limit that's hit is usually the global one not the per app one also why do you have it at 128

Petris•3mo ago

the default seems to be 8192

wasabi•3mo ago

watch != instance

MazranelOP•3mo ago

That seems to be Kubuntu's default Nvm, just read the above comment Ah. I'm not sure what else could be causing the limit to be hit though, as there are only about 3 applications running at a time

wasabi•3mo ago

You can probably check something in procfs to see how many are used

MazranelOP•3mo ago

I could add a check before the few gets set up

wasabi•3mo ago

or you could just go look. with your eyes

MazranelOP•3mo ago

I meant as a warning for users. Y'know, so they don't just have to deal with some random error that might look like gibberish to them We don't want Microsoft error messages

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FileSystemWatcher causes user limit exceptions on Kubuntu Linux