fix trimming

src/ImageSharp/Memory/Allocators/Internals/UniformUnmanagedMemoryPool.cs

@@ -44,6 +44,7 @@ namespace SixLabors.ImageSharp.Memory.Internals
 #if NETCORE31COMPATIBLE
                 Gen2GcCallback.Register(s => ((UniformUnmanagedMemoryPool)s).Trim(), this);
 #endif
+                this.lastTrimTimestamp = Stopwatch.ElapsedMilliseconds;
             }
         }
 
@@ -262,6 +263,7 @@ namespace SixLabors.ImageSharp.Memory.Internals
                 // Trim all:
                 for (int i = this.index; i < buffersLocal.Length && buffersLocal[i] != null; i++)
                 {
+                    buffersLocal[i].Dispose();
                     buffersLocal[i] = null;
                 }
             }
@@ -316,13 +318,12 @@ namespace SixLabors.ImageSharp.Memory.Internals
         public class TrimSettings
         {
             // Trim half of the retained pool buffers every minute.
-            public int TrimPeriodMilliseconds { get; set; } = 20_000;
+            public int TrimPeriodMilliseconds { get; set; } = 60_000;
 
             public float Rate { get; set; } = 0.5f;
 
-            // Be more strict about high pressure threshold than ArrayPool<T>.Shared.
-            // A 32 bit process can OOM before reaching HighMemoryLoadThresholdBytes.
-            public float HighPressureThresholdRate { get; set; } = 0.5f;
+            // Be more strict about high pressure on 32 bit.
+            public unsafe float HighPressureThresholdRate { get; set; } = sizeof(IntPtr) == 8 ? 0.9f : 0.6f;
 
             public bool Enabled => this.Rate > 0;
 

tests/ImageSharp.Tests.ProfilingSandbox/LoadResizeSaveParallelMemoryStress.cs

@@ -232,8 +232,8 @@ namespace SixLabors.ImageSharp.Tests.ProfilingSandbox
             [Option('f', "file", Required = false, Default = null)]
             public string FileOutput { get; set; }
 
-            [Option('t', "trim-time", Required = false, Default = 60)]
-            public int TrimTimeSeconds { get; set; }
+            [Option('t', "trim-time", Required = false, Default = null)]
+            public int? TrimTimeSeconds { get; set; }
 
             public static CommandLineOptions Parse(string[] args)
             {
@@ -257,15 +257,27 @@ namespace SixLabors.ImageSharp.Tests.ProfilingSandbox
                         return ArrayPoolMemoryAllocator.CreateDefault();
 #pragma warning restore CS0618
                     case AllocatorKind.Unmanaged:
-                        return new UniformUnmanagedMemoryPoolMemoryAllocator(
-                            1024 * 1024,
-                            (int)B(this.MaxContiguousPoolBufferMegaBytes),
-                            B(this.MaxPoolSizeMegaBytes),
-                            (int)B(this.MaxCapacityOfUnmanagedBuffersMegaBytes),
-                            new UniformUnmanagedMemoryPool.TrimSettings
-                            {
-                                TrimPeriodMilliseconds = this.TrimTimeSeconds * 100
-                            });
+                        if (this.TrimTimeSeconds.HasValue)
+                        {
+                            return new UniformUnmanagedMemoryPoolMemoryAllocator(
+                                1024 * 1024,
+                                (int)B(this.MaxContiguousPoolBufferMegaBytes),
+                                B(this.MaxPoolSizeMegaBytes),
+                                (int)B(this.MaxCapacityOfUnmanagedBuffersMegaBytes),
+                                new UniformUnmanagedMemoryPool.TrimSettings
+                                {
+                                    TrimPeriodMilliseconds = this.TrimTimeSeconds.Value * 1000
+                                });
+                        }
+                        else
+                        {
+                            return new UniformUnmanagedMemoryPoolMemoryAllocator(
+                                1024 * 1024,
+                                (int)B(this.MaxContiguousPoolBufferMegaBytes),
+                                B(this.MaxPoolSizeMegaBytes),
+                                (int)B(this.MaxCapacityOfUnmanagedBuffersMegaBytes));
+                        }
+
                     default:
                         throw new ArgumentOutOfRangeException();
                 }