Strategy change

src/core/lib/slice/slice_buffer.c

@@ -51,19 +51,23 @@ static void maybe_embiggen(grpc_slice_buffer *sb) {
   size_t slice_count = sb->count + slice_offset;
 
   if (slice_count == sb->capacity) {
-    sb->capacity = GROW(sb->capacity);
-    GPR_ASSERT(sb->capacity > slice_count);
-    if (sb->base_slices == sb->inlined) {
-      sb->base_slices = gpr_malloc(sb->capacity * sizeof(grpc_slice));
-      memcpy(sb->base_slices, sb->inlined, slice_count * sizeof(grpc_slice));
-      sb->slices = sb->base_slices + slice_offset;
+    if (sb->base_slices != sb->slices) {
+      /* Make room by moving elements if there's still space unused */
+      memmove(sb->base_slices, sb->slices, sb->count * sizeof(grpc_slice));
+      sb->slices = sb->base_slices;
     } else {
-      if (sb->base_slices != sb->slices) {
-        memmove(sb->base_slices, sb->slices, sb->count * sizeof(grpc_slice));
+      /* Allocate more memory if no more space is available */
+      sb->capacity = GROW(sb->capacity);
+      GPR_ASSERT(sb->capacity > slice_count);
+      if (sb->base_slices == sb->inlined) {
+        sb->base_slices = gpr_malloc(sb->capacity * sizeof(grpc_slice));
+        memcpy(sb->base_slices, sb->inlined, slice_count * sizeof(grpc_slice));
+      } else {
+        sb->base_slices =
+            gpr_realloc(sb->base_slices, sb->capacity * sizeof(grpc_slice));
       }
-      sb->base_slices =
-          gpr_realloc(sb->base_slices, sb->capacity * sizeof(grpc_slice));
-      sb->slices = sb->base_slices;
+
+      sb->slices = sb->base_slices + slice_offset;
     }
   }
 }