[PATCH] mm/hugetlb: skip report_hugepages() output when no hugepages configured

[lirongqing <lirongqing@baidu.com>]

From: Li RongQing <lirongqing@baidu.com> 

Avoid unnecessary report_hugepages() output and processing when
max_huge_pages is 0. This eliminates redundant log messages for
unconfigured hugepage sizes and saves CPU cycles during boot.

Before this change, the kernel would always print registration messages
even for hugepage sizes with zero pre-allocated pages:

[    4.118953] HugeTLB: registered 2.00 MiB page size, pre-allocated 0 pages
[    4.122920] HugeTLB: 28 KiB vmemmap can be freed for a 2.00 MiB page
[    4.126920] HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages
[    4.130920] HugeTLB: 16380 KiB vmemmap can be freed for a 1.00 GiB page

Now these messages are suppressed when no pages are configured.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 mm/hugetlb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index af7c36f..9fb9311 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3733,6 +3733,9 @@ static void __init report_hugepages(void)
 	for_each_hstate(h) {
 		char buf[32];
 
+		if (!h->max_huge_pages)
+			continue;
+
 		nrinvalid = hstate_boot_nrinvalid[hstate_index(h)];
 		h->max_huge_pages -= nrinvalid;
 
-- 
2.9.4