Re: [PATCH 2/3] mm/vmalloc: Switch to bulk allocator in __vmalloc_area_node()

+	if (!page_order) {
+		area->nr_pages = alloc_pages_bulk_array_node(
+			gfp_mask, node, nr_small_pages, area->pages);
+	} else {
+		/*
+		 * Careful, we allocate and map page_order pages, but tracking is done
+		 * per PAGE_SIZE page so as to keep the vm_struct APIs independent of

Comments over 80 lines are completely unreadable, so please avoid them.

+		 * the physical/mapped size.
+		 */
+		while (area->nr_pages < nr_small_pages) {
+			struct page *page;
+			int i;
+
+			/* Compound pages required for remap_vmalloc_page */
+			page = alloc_pages_node(node, gfp_mask | __GFP_COMP, page_order);
+			if (unlikely(!page))
+				break;
 
+			for (i = 0; i < (1U << page_order); i++)
+				area->pages[area->nr_pages + i] = page + i;
 
+			if (gfpflags_allow_blocking(gfp_mask))
+				cond_resched();
+
+			area->nr_pages += 1U << page_order;
+		}

In fact splitting this whole high order allocation logic into a little
helper would massivel benefit the function by ordering it more logical
and reducing a level of indentation.

+	/*
+	 * If not enough pages were obtained to accomplish an
+	 * allocation request, free them via __vfree() if any.
+	 */
+	if (area->nr_pages != nr_small_pages) {
+		warn_alloc(gfp_mask, NULL,
+			"vmalloc size %lu allocation failure: "
+			"page order %u allocation failed",
+			area->nr_pages * PAGE_SIZE, page_order);
+		goto fail;
+	}

From reading __alloc_pages_bulk not allocating all pages is something
that cn happen fairly easily.  Shouldn't we try to allocate the missing
pages manually and/ore retry here?

+
+	if (vmap_pages_range(addr, addr + size, prot, area->pages, page_shift) < 0) {

Another pointlessly long line.