Minimum RSS threshold to do background GC

Author: qunaibit

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/capi/CApiContext.java

@@ -635,6 +635,11 @@ private BackgroundGCTask(PythonContext context) {
          */
         static final double GC_RSS_THRESHOLD = Integer.getInteger("python.RSSThreshold", 30) / 100.0;
 
+        /**
+         * RSS minimum memory (in megabytes) start calling System.gc(). Default is 4GB.
+         */
+        static final double GC_RSS_MINIMUM = Integer.getInteger("python.RSSMinimumMB", 4096);
+
         Long getCurrentRSS() {
             if (nativeSymbol == null) {
                 nativeSymbol = CApiContext.getNativeSymbol(null, NativeCAPISymbol.FUN_GET_CURRENT_RSS);
@@ -680,6 +685,10 @@ private void perform() {
                 return;
             }
 
+            if (rss < GC_RSS_MINIMUM) {
+                return;
+            }
+
             // skip GC if no new native weakrefs have been created.
             int currentWeakrefCount = context.nativeContext.nativeLookup.size();
             if (currentWeakrefCount < this.previousWeakrefCount || this.previousWeakrefCount == -1) {