MAGETWO-67010: [Performance] Swatches real server side optimization

Author: AVoskoboinikov

app/code/Magento/ConfigurableProduct/Block/Product/View/Type/Configurable.php

@@ -154,14 +154,14 @@ public function hasOptions()
     public function getAllowProducts()
     {
         if (!$this->hasAllowProducts()) {
-            $products = [];
             $skipSaleableCheck = $this->catalogProduct->getSkipSaleableCheck();
-            $allProducts = $this->getProduct()->getTypeInstance()->getUsedProducts($this->getProduct(), null);
-            foreach ($allProducts as $product) {
-                if ($product->isSaleable() || $skipSaleableCheck) {
-                    $products[] = $product;
-                }
+
+            if ($skipSaleableCheck) {
+                $products = $this->getProduct()->getTypeInstance()->getUsedProducts($this->getProduct(), null);
+            } else {
+                $products = $this->getProduct()->getTypeInstance()->getSalableUsedProducts($this->getProduct(), null);
             }
+
             $this->setAllowProducts($products);
         }
         return $this->getData('allow_products');