diff --git a/memory/build/mozjemalloc.cpp b/memory/build/mozjemalloc.cpp
index 1fd371f6444a..165078360e3a 100644
--- a/memory/build/mozjemalloc.cpp
+++ b/memory/build/mozjemalloc.cpp
@@ -4250,7 +4250,7 @@ inline void MozJemalloc::jemalloc_stats_internal(
   aStats->opt_junk = opt_junk;
   aStats->opt_zero = opt_zero;
   aStats->quantum = kQuantum;
-  aStats->small_max = kMaxQuantumClass;
+  aStats->quantum_max = kMaxQuantumClass;
   aStats->large_max = gMaxLargeClass;
   aStats->chunksize = kChunkSize;
   aStats->page_size = gPageSize;
diff --git a/memory/build/mozjemalloc_types.h b/memory/build/mozjemalloc_types.h
index e414c2cc583f..d86768b53eef 100644
--- a/memory/build/mozjemalloc_types.h
+++ b/memory/build/mozjemalloc_types.h
@@ -75,11 +75,12 @@ typedef struct arena_params_s {
 // file.
 typedef struct {
   // Run-time configuration settings.
-  bool opt_junk;     // Fill allocated memory with kAllocJunk?
-  bool opt_zero;     // Fill allocated memory with 0x0?
-  size_t narenas;    // Number of arenas.
-  size_t quantum;    // Allocation quantum.
-  size_t small_max;  // Max quantum-spaced allocation size.
+  bool opt_junk;       // Fill allocated memory with kAllocJunk?
+  bool opt_zero;       // Fill allocated memory with 0x0?
+  size_t narenas;      // Number of arenas.
+  size_t quantum;      // Allocation quantum.
+  size_t quantum_max;  // Max quantum-spaced allocation size.
+  // The next size class, sub-pagesize's max is always page_size/2.
   size_t large_max;  // Max sub-chunksize allocation size.
   size_t chunksize;  // Size of each virtual memory mapping.
   size_t page_size;  // Size of pages.