diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index 6721f3a8bb..3807050cbe 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -1227,16 +1227,6 @@ HaveSpan:
 		// heap_released since we already did so earlier.
 		sysUsed(unsafe.Pointer(s.base()), s.npages<<_PageShift)
 		s.scavenged = false
-
-		// Since we allocated out of a scavenged span, we just
-		// grew the RSS. Mitigate this by scavenging enough free
-		// space to make up for it but only if we need to.
-		//
-		// scavengeLocked may cause coalescing, so prevent
-		// coalescing with s by temporarily changing its state.
-		s.state = mSpanManual
-		h.scavengeIfNeededLocked(s.npages * pageSize)
-		s.state = mSpanFree
 	}
 
 	h.setSpans(s.base(), npage, s)
@@ -1312,6 +1302,10 @@ func (h *mheap) grow(npage uintptr) bool {
 //
 // h must be locked.
 func (h *mheap) growAddSpan(v unsafe.Pointer, size uintptr) {
+	// Scavenge some pages to make up for the virtual memory space
+	// we just allocated, but only if we need to.
+	h.scavengeIfNeededLocked(size)
+
 	s := (*mspan)(h.spanalloc.alloc())
 	s.init(uintptr(v), size/pageSize)
 	h.setSpans(s.base(), s.npages, s)