Scale dirty page thresholds by page size ratio

Author: bpowers

src/meshable_arena.cc

@@ -391,7 +391,9 @@ void MeshableArena::partialScavenge() {
 }
 
 void MeshableArena::scavenge(bool force) {
-  if (!force && _dirtyPageCount < kMinDirtyPageThreshold) {
+  const size_t minDirtyPageThreshold = (kMinDirtyPageThreshold * kPageSizeMin) / getPageSize();
+
+  if (!force && _dirtyPageCount < minDirtyPageThreshold) {
     return;
   }
 

src/meshable_arena.h

@@ -203,7 +203,9 @@ class MeshableArena : public mesh::OneWayMmapHeap {
       _dirty[span.spanClass()].push_back(span);
       _dirtyPageCount += span.length;
 
-      if (_dirtyPageCount > kMaxDirtyPageThreshold) {
+      const size_t maxDirtyPageThreshold = (kMaxDirtyPageThreshold * kPageSizeMin) / getPageSize();
+
+      if (_dirtyPageCount > maxDirtyPageThreshold) {
         // do a full scavenge with a probability 1/10
         if (_fastPrng.inRange(0, 9) == 9) {
           scavenge(true);