On 2/19/21 4:39 AM, Chen Wandun wrote:
> If hugetlb_cma is enabled, it will skip boot time allocation
> when allocating gigantic page, that doesn't means allocation
> failure, so suppress this warning info.
>
Normally the addition of warning messages is discouraged. However, in
this case the additional message provides value. Why?
Prior to the commit cf11e85fc08c, one could have a kernel command line
that contains:
hugepagesz=1G hugepages=16
This would allocate 16 1G pages at boot time.
After the commit, someone could specify a command line containing:
hugepagesz=1G hugepages=16 hugetlb_cma=16G
In this case, 16G of CMA will be reserved for 1G huge page allocations
after boot time. The parameter 'hugepages=16' is ignored, and the warning
message is logged. The warning message should only be logged when the
kernel parameter 'hugepages=' is ignored.
IMO, it make sense to log a warning if ignoring a user specified parameter.
The user should not be attempting boot time allocation and CMA reservation
for 1G pages.
I do not think we should drop the warning as the it tells the user thay
have specified two incompatible allocation options.
--
Mike Kravetz
> Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
> Signed-off-by: Chen Wandun <chenwandun@xxxxxxxxxx>
> ---
> mm/hugetlb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index b6992297aa16..98a49cb9250c 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2465,7 +2465,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
> if (hstate_is_gigantic(h)) {
> if (hugetlb_cma_size) {
> pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
> - break;
> + goto free;
> }
> if (!alloc_bootmem_huge_page(h))
> break;
> @@ -2483,7 +2483,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
> h->max_huge_pages, buf, i);
> h->max_huge_pages = i;
> }
> -
> +free:
> kfree(node_alloc_noretry);
> }
>
>
