feat(chunk): trigger eviction by freeratio in cache add path (#5970)

Signed-off-by: myron369 <[email protected]>

Author: myron369

pkg/chunk/disk_cache.go

@@ -146,6 +146,9 @@ func newCacheStore(m *cacheManagerMetrics, dir string, cacheSize, maxItems int64
 	}
 	logger.Infof("Disk cache (%s): used ratio - [space %s%%, inode %s%%]",
 		c.dir, humanize.FtoaWithDigits(float64((1-usage.br)*100), 1), humanize.FtoaWithDigits(float64((1-usage.fr)*100), 1))
+
+	c.setlimitByFreeRatio(usage, c.freeRatio)
+
 	c.createLockFile()
 	go c.checkLockFile()
 	go c.flush()
@@ -159,6 +162,21 @@ func newCacheStore(m *cacheManagerMetrics, dir string, cacheSize, maxItems int64
 	return c
 }
 
+func (cache *cacheStore) setlimitByFreeRatio(usage DiskFreeRatio, freeRatio float32) {
+	sizeLimit := int64(float64(1-freeRatio) * float64(usage.spaceCap))
+	inodeLimit := int64(float64(1-freeRatio) * float64(usage.inodeCap))
+	if sizeLimit < cache.capacity {
+		limit := cache.capacity
+		cache.capacity = sizeLimit
+		logger.Infof("Adjusted cache capacity based on freeratio: from %d to %d bytes", limit, cache.capacity)
+	}
+	if inodeLimit < cache.maxItems || cache.maxItems == 0 {
+		limit := cache.maxItems
+		cache.maxItems = inodeLimit
+		logger.Infof("Adjusted max items based on freeratio: from %d to %d items", limit, cache.maxItems)
+	}
+}
+
 func (cache *cacheStore) lockFilePath() string {
 	return filepath.Join(cache.dir, ".lock")
 }

pkg/chunk/disk_cache_test.go

@@ -407,3 +407,23 @@ func TestAtimeNotLost(t *testing.T) {
 		t.Fatalf("CacheStore key %s atime lost after scan, before: %d, after: %d", key, atimeMem, atimeAfterScan)
 	}
 }
+func TestSetlimitByFreeRatio(t *testing.T) {
+	dir := t.TempDir()
+	cache := newCacheStore(nil, dir, 1<<30, 1000, 1, &defaultConf, nil)
+
+	usage := DiskFreeRatio{
+		spaceCap: 1 << 30,
+		inodeCap: 1000,
+	}
+	freeRatio := float32(0.2)
+	cache.setlimitByFreeRatio(usage, 0.2)
+
+	expectedSizeLimit := int64((1 - freeRatio + 0.05) * float32(usage.spaceCap))
+	if cache.capacity > expectedSizeLimit {
+		t.Fatalf("Expected capacity <= %d, but got %d", expectedSizeLimit, cache.capacity)
+	}
+	expectedInodeLimit := int64((1 - freeRatio + 0.05) * float32(usage.inodeCap))
+	if cache.maxItems > expectedInodeLimit && cache.maxItems != 0 {
+		t.Fatalf("Expected maxItems <= %d, but got %d", expectedInodeLimit, cache.maxItems)
+	}
+}