From: Li RongQing <lirongqing@baidu.com>
Date: Thu, 14 Aug 2025 10:23:33 +0000 (+0800)
Subject: mm/hugetlb: early exit from hugetlb_pages_alloc_boot() when max_huge_pages=0
X-Git-Tag: v6.18-rc1~130^2~258
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b322e88b3d553e85b4e15779491c70022783faa4;p=thirdparty%2Fkernel%2Fstable.git

mm/hugetlb: early exit from hugetlb_pages_alloc_boot() when max_huge_pages=0

Optimize hugetlb_pages_alloc_boot() to return immediately when
max_huge_pages is 0, avoiding unnecessary CPU cycles and the below log
message when hugepages aren't configured in the kernel command line.
[    3.702280] HugeTLB: allocation took 0ms with hugepage_allocation_threads=32

Link: https://lkml.kernel.org/r/20250814102333.4428-1-lirongqing@baidu.com
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Tested-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 753f99b4c7186..514fab5a20ef8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3654,6 +3654,9 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 		return;
 	}
 
+	if (!h->max_huge_pages)
+		return;
+
 	/* do node specific alloc */
 	if (hugetlb_hstate_alloc_pages_specific_nodes(h))
 		return;