[PATCH][v2] mm/hugetlb: early exit from hugetlb_pages_alloc_boot() when max_huge_pages=0

[lirongqing]

From: Li RongQing <lirongqing@xxxxxxxxx>

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

Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
---
diff with v1: adding the reduced log messages in commit header 

 mm/hugetlb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 753f99b..514fab5 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;
-- 
2.9.4