Implement limiting caches (#13605)

* Implement basic expiring cache for LibraryManager

* Add expiring cache to more places

* Rider why

* Make DirectoryService caches static

* Use FastConcurrentLru

* Reduce default cache size

* Simplify DirectoryService caches

* Make directory service cache size at least 128

1 files changed, 8 insertions, 9 deletions

diff --git a/MediaBrowser.Controller/Providers/DirectoryService.cs b/MediaBrowser.Controller/Providers/DirectoryService.cs
index 474f09dc5..4fca94477 100644
--- a/MediaBrowser.Controller/Providers/DirectoryService.cs
+++ b/MediaBrowser.Controller/Providers/DirectoryService.cs
@@ -1,22 +1,21 @@
 #pragma warning disable CS1591
 
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using BitFaster.Caching.Lru;
 using MediaBrowser.Model.IO;
 
 namespace MediaBrowser.Controller.Providers
 {
     public class DirectoryService : IDirectoryService
     {
-        private readonly IFileSystem _fileSystem;
-
-        private readonly ConcurrentDictionary<string, FileSystemMetadata[]> _cache = new(StringComparer.Ordinal);
+        // These caches are primarily used for scanning so no reason to have them be large.
+        private static readonly FastConcurrentLru<string, FileSystemMetadata[]> _cache = new(Environment.ProcessorCount, Math.Max(128, Environment.ProcessorCount * 10), StringComparer.Ordinal);
+        private static readonly FastConcurrentLru<string, FileSystemMetadata> _fileCache = new(Environment.ProcessorCount, Math.Max(128, Environment.ProcessorCount * 10), StringComparer.Ordinal);
+        private static readonly FastConcurrentLru<string, List<string>> _filePathCache = new(Environment.ProcessorCount, Math.Max(128, Environment.ProcessorCount * 10), StringComparer.Ordinal);
 
-        private readonly ConcurrentDictionary<string, FileSystemMetadata> _fileCache = new(StringComparer.Ordinal);
-
-        private readonly ConcurrentDictionary<string, List<string>> _filePathCache = new(StringComparer.Ordinal);
+        private readonly IFileSystem _fileSystem;
 
         public DirectoryService(IFileSystem fileSystem)
         {
@@ -74,13 +73,13 @@ namespace MediaBrowser.Controller.Providers
 
         public FileSystemMetadata? GetFileSystemEntry(string path)
         {
-            if (!_fileCache.TryGetValue(path, out var result))
+            if (!_fileCache.TryGet(path, out var result))
             {
                 var file = _fileSystem.GetFileSystemInfo(path);
                 if (file?.Exists ?? false)
                 {
                     result = file;
-                    _fileCache.TryAdd(path, result);
+                    _fileCache.AddOrUpdate(path, result);
                 }
             }