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

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

Posted by lirongqing 3 weeks, 1 day ago

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

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

Posted by David Hildenbrand 3 weeks, 1 day ago

On 10.09.25 11:03, lirongqing wrote:
> 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.

Well, there is valuable information in there, especially given that we 
can allocate these hugetlb pages later.

So I think we want to keep printing that information.

-- 
Cheers

David / dhildenb