[RFC PATCH v2 1/5] hugetlb: code clean for hugetlb_hstate_alloc_pages

[Gang Li <gang.li@linux.dev>]

The readability of `hugetlb_hstate_alloc_pages` is poor. By cleaning the
code, its readability can be improved, facilitating future modifications.

This patch extracts two functions to reduce the complexity of
`hugetlb_hstate_alloc_pages` and has no functional changes.

- hugetlb_hstate_alloc_pages_node_specific() to handle iterates through
  each online node and performs allocation if necessary.
- hugetlb_hstate_alloc_pages_report() report error during allocation.
  And the value of h->max_huge_pages is updated accordingly.

Signed-off-by: Gang Li <gang.li@linux.dev>
---
 mm/hugetlb.c | 46 +++++++++++++++++++++++++++++-----------------
 1 file changed, 29 insertions(+), 17 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 51f50bb3dc092..252d6866a0af8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3475,6 +3475,33 @@ static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
 	h->max_huge_pages_node[nid] = i;
 }
 
+static bool __init hugetlb_hstate_alloc_pages_node_specific(struct hstate *h)
+{
+	int i;
+	bool node_specific_alloc = false;
+
+	for_each_online_node(i) {
+		if (h->max_huge_pages_node[i] > 0) {
+			hugetlb_hstate_alloc_pages_onenode(h, i);
+			node_specific_alloc = true;
+		}
+	}
+
+	return node_specific_alloc;
+}
+
+static void __init hugetlb_hstate_alloc_pages_report(unsigned long allocated, struct hstate *h)
+{
+	if (allocated < h->max_huge_pages) {
+		char buf[32];
+
+		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
+		pr_warn("HugeTLB: allocating %lu of page size %s failed.  Only allocated %lu hugepages.\n",
+			h->max_huge_pages, buf, allocated);
+		h->max_huge_pages = allocated;
+	}
+}
+
 /*
  * NOTE: this routine is called in different contexts for gigantic and
  * non-gigantic pages.
@@ -3492,7 +3519,6 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 	struct folio *folio;
 	LIST_HEAD(folio_list);
 	nodemask_t *node_alloc_noretry;
-	bool node_specific_alloc = false;
 
 	/* skip gigantic hugepages allocation if hugetlb_cma enabled */
 	if (hstate_is_gigantic(h) && hugetlb_cma_size) {
@@ -3501,14 +3527,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 	}
 
 	/* do node specific alloc */
-	for_each_online_node(i) {
-		if (h->max_huge_pages_node[i] > 0) {
-			hugetlb_hstate_alloc_pages_onenode(h, i);
-			node_specific_alloc = true;
-		}
-	}
-
-	if (node_specific_alloc)
+	if (hugetlb_hstate_alloc_pages_node_specific(h))
 		return;
 
 	/* below will do all node balanced alloc */
@@ -3551,14 +3570,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 	/* list will be empty if hstate_is_gigantic */
 	prep_and_add_allocated_folios(h, &folio_list);
 
-	if (i < h->max_huge_pages) {
-		char buf[32];
-
-		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
-		pr_warn("HugeTLB: allocating %lu of page size %s failed.  Only allocated %lu hugepages.\n",
-			h->max_huge_pages, buf, i);
-		h->max_huge_pages = i;
-	}
+	hugetlb_hstate_alloc_pages_report(i, h);
 	kfree(node_alloc_noretry);
 }
 
-- 
2.30.2