diff --git a/src/runtime/mcache.go b/src/runtime/mcache.go
index 4df1361833..c80c5b095a 100644
--- a/src/runtime/mcache.go
+++ b/src/runtime/mcache.go
@@ -8,14 +8,25 @@ import "unsafe"
 
 // Per-thread (in Go, per-P) cache for small objects.
 // No locking needed because it is per-thread (per-P).
+//
+// mcaches are allocated from non-GC'd memory, so any heap pointers
+// must be specially handled.
 type mcache struct {
 	// The following members are accessed on every malloc,
 	// so they are grouped here for better caching.
 	next_sample      int32   // trigger heap sample after allocating this many bytes
 	local_cachealloc uintptr // bytes allocated from cache since last lock of heap
 	local_scan       uintptr // bytes of scannable heap allocated
+
 	// Allocator cache for tiny objects w/o pointers.
 	// See "Tiny allocator" comment in malloc.go.
+
+	// tiny points to the beginning of the current tiny block, or
+	// nil if there is no current tiny block.
+	//
+	// tiny is a heap pointer. Since mcache is in non-GC'd memory,
+	// we handle it by clearing it in releaseAll during mark
+	// termination.
 	tiny             unsafe.Pointer
 	tinyoffset       uintptr
 	local_tinyallocs uintptr // number of tiny allocs not counted in other stats
@@ -127,4 +138,7 @@ func (c *mcache) releaseAll() {
 			c.alloc[i] = &emptymspan
 		}
 	}
+	// Clear tinyalloc pool.
+	c.tiny = nil
+	c.tinyoffset = 0
 }
diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 7d5b372ba1..e04c1a8459 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -1744,17 +1744,6 @@ func clearpools() {
 		sched.deferpool[i] = nil
 	}
 	unlock(&sched.deferlock)
-
-	for _, p := range &allp {
-		if p == nil {
-			break
-		}
-		// clear tinyalloc pool
-		if c := p.mcache; c != nil {
-			c.tiny = nil
-			c.tinyoffset = 0
-		}
-	}
 }
 
 // Timing