On 30.11.20 16:18, Muchun Song wrote:
> The purpose of introducing HUGETLB_PAGE_FREE_VMEMMAP is to configure
> whether to enable the feature of freeing unused vmemmap associated
> with HugeTLB pages. And this is just for dependency check. Now only
> support x86.
x86 - i386 and x86-64? (I assume the latter only ;) )
>
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> ---
> arch/x86/mm/init_64.c | 2 +-
> fs/Kconfig | 14 ++++++++++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 0a45f062826e..0435bee2e172 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -1225,7 +1225,7 @@ static struct kcore_list kcore_vsyscall;
>
> static void __init register_page_bootmem_info(void)
> {
> -#ifdef CONFIG_NUMA
> +#if defined(CONFIG_NUMA) || defined(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP)
> int i;
>
Why does this hunk belong into this patch? Looks like this should go
into another patch.
> for_each_online_node(i)
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 976e8b9033c4..4961dd488444 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -245,6 +245,20 @@ config HUGETLBFS
> config HUGETLB_PAGE
> def_bool HUGETLBFS
>
> +config HUGETLB_PAGE_FREE_VMEMMAP
> + def_bool HUGETLB_PAGE
> + depends on X86
> + depends on SPARSEMEM_VMEMMAP
> + depends on HAVE_BOOTMEM_INFO_NODE
> + help
> + When using HUGETLB_PAGE_FREE_VMEMMAP, the system can save up some
> + memory from pre-allocated HugeTLB pages when they are not used.
> + 6 pages per 2MB HugeTLB page and 4094 per 1GB HugeTLB page.
Calculations only apply to 4k base pages, no? (maybe generalize this a
bit or mention 4k base pages - I'm pretty sure we'll see the "depends on
X86" part fairly soon if this goes upstream)
--
Thanks,
David / dhildenb
