changes

2025-10-06 03:47:24 +09:00
parent 39784a1fea
commit c35650438c
22 changed files with 1480 additions and 184 deletions
--- a/LightlessSync/Services/PairProcessingLimiter.cs
+++ b/LightlessSync/Services/PairProcessingLimiter.cs
@@ -0,0 +1,220 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using LightlessSync.LightlessConfiguration;
+using LightlessSync.Services.Mediator;
+using Microsoft.Extensions.Logging;
+
+namespace LightlessSync.Services;
+
+public sealed class PairProcessingLimiter : DisposableMediatorSubscriberBase
+{
+    private const int HardLimit = 32;
+    private readonly LightlessConfigService _configService;
+    private readonly object _limitLock = new();
+    private readonly SemaphoreSlim _semaphore;
+    private int _currentLimit;
+    private int _pendingReductions;
+    private int _waiting;
+    private int _inFlight;
+
+    public PairProcessingLimiter(ILogger<PairProcessingLimiter> logger, LightlessMediator mediator, LightlessConfigService configService)
+        : base(logger, mediator)
+    {
+        _configService = configService;
+        _currentLimit = CalculateLimit();
+        var initialCount = _configService.Current.EnablePairProcessingLimiter ? _currentLimit : HardLimit;
+        _semaphore = new SemaphoreSlim(initialCount, HardLimit);
+
+        Mediator.Subscribe<PairProcessingLimitChangedMessage>(this, _ => UpdateSemaphoreLimit());
+    }
+
+    public ValueTask<IAsyncDisposable> AcquireAsync(CancellationToken cancellationToken)
+    {
+        return WaitInternalAsync(cancellationToken);
+    }
+
+    public PairProcessingLimiterSnapshot GetSnapshot()
+    {
+        lock (_limitLock)
+        {
+            var enabled = IsEnabled;
+            var limit = enabled ? _currentLimit : CalculateLimit();
+            var waiting = Math.Max(0, Volatile.Read(ref _waiting));
+            var inFlight = Math.Max(0, Volatile.Read(ref _inFlight));
+            return new PairProcessingLimiterSnapshot(enabled, limit, inFlight, waiting);
+        }
+    }
+
+    private bool IsEnabled => _configService.Current.EnablePairProcessingLimiter;
+
+    private async ValueTask<IAsyncDisposable> WaitInternalAsync(CancellationToken token)
+    {
+        if (!IsEnabled)
+        {
+            return NoopReleaser.Instance;
+        }
+
+        Interlocked.Increment(ref _waiting);
+        try
+        {
+            await _semaphore.WaitAsync(token).ConfigureAwait(false);
+        }
+        catch
+        {
+            Interlocked.Decrement(ref _waiting);
+            throw;
+        }
+
+        Interlocked.Decrement(ref _waiting);
+
+        if (!IsEnabled)
+        {
+            _semaphore.Release();
+            return NoopReleaser.Instance;
+        }
+
+        Interlocked.Increment(ref _inFlight);
+        return new Releaser(this);
+    }
+
+    private void UpdateSemaphoreLimit()
+    {
+        lock (_limitLock)
+        {
+            var enabled = IsEnabled;
+            var desiredLimit = CalculateLimit();
+
+            if (!enabled)
+            {
+                var releaseAmount = HardLimit - _semaphore.CurrentCount;
+                if (releaseAmount > 0)
+                {
+                    try
+                    {
+                        _semaphore.Release(releaseAmount);
+                    }
+                    catch (SemaphoreFullException)
+                    {
+                        // ignore, already at max
+                    }
+                }
+
+                _currentLimit = desiredLimit;
+                _pendingReductions = 0;
+                return;
+            }
+
+            if (desiredLimit == _currentLimit)
+            {
+                return;
+            }
+
+            if (desiredLimit > _currentLimit)
+            {
+                var increment = desiredLimit - _currentLimit;
+                var allowed = Math.Min(increment, HardLimit - _semaphore.CurrentCount);
+                if (allowed > 0)
+                {
+                    _semaphore.Release(allowed);
+                }
+            }
+            else
+            {
+                var decrement = _currentLimit - desiredLimit;
+                var removed = 0;
+                while (removed < decrement && _semaphore.Wait(0))
+                {
+                    removed++;
+                }
+
+                var remaining = decrement - removed;
+                if (remaining > 0)
+                {
+                    _pendingReductions += remaining;
+                }
+            }
+
+            _currentLimit = desiredLimit;
+            Logger.LogDebug("Pair processing concurrency updated to {limit} (pending reductions: {pending})", _currentLimit, _pendingReductions);
+        }
+    }
+
+    private int CalculateLimit()
+    {
+        var configured = _configService.Current.MaxConcurrentPairApplications;
+        return Math.Clamp(configured, 1, HardLimit);
+    }
+
+    private void ReleaseOne()
+    {
+        var inFlight = Interlocked.Decrement(ref _inFlight);
+        if (inFlight < 0)
+        {
+            Interlocked.Exchange(ref _inFlight, 0);
+        }
+
+        if (!IsEnabled)
+        {
+            return;
+        }
+
+        lock (_limitLock)
+        {
+            if (_pendingReductions > 0)
+            {
+                _pendingReductions--;
+                return;
+            }
+        }
+
+        _semaphore.Release();
+    }
+
+    protected override void Dispose(bool disposing)
+    {
+        base.Dispose(disposing);
+        if (!disposing)
+        {
+            return;
+        }
+
+        _semaphore.Dispose();
+    }
+
+    private sealed class Releaser : IAsyncDisposable
+    {
+        private PairProcessingLimiter? _owner;
+
+        public Releaser(PairProcessingLimiter owner)
+        {
+            _owner = owner;
+        }
+
+        public ValueTask DisposeAsync()
+        {
+            var owner = Interlocked.Exchange(ref _owner, null);
+            owner?.ReleaseOne();
+            return ValueTask.CompletedTask;
+        }
+    }
+
+    private sealed class NoopReleaser : IAsyncDisposable
+    {
+        public static readonly NoopReleaser Instance = new();
+
+        private NoopReleaser()
+        {
+        }
+
+        public ValueTask DisposeAsync()
+        {
+            return ValueTask.CompletedTask;
+        }
+    }
+}
+
+public readonly record struct PairProcessingLimiterSnapshot(bool IsEnabled, int Limit, int InFlight, int Waiting)
+{
+    public int Remaining => Math.Max(0, Limit - InFlight);
+}