Re: [PATCH v3 0/2] mm: optimize HugeTLB bootmem hugepage init

[Mike Rapoport <rppt@kernel.org>]

Hi,

On Thu, Nov 12, 2026 at 07:28:14PM +0800, Li Zhe wrote:
> This series speeds up the fallback initialization path for HugeTLB tail
> struct pages during boot-time hugepage allocation, when HugeTLB vmemmap
> optimization (HVO) is unavailable or fails.
> 
> Patch 1 factors the PFN-dependent template refresh from the ZONE_DEVICE
> template-copy path into memmap_init_refresh_pfn_fields().  The
> ZONE_DEVICE path keeps its memcpy_nontemporal() copy primitive.
> 
> Patch 2 adds a HugeTLB-specific copy helper in
> hugetlb_folio_init_tail_vmemmap(): initialize the first tail page
> normally, then initialize the remaining tail pages by copying that page
> with memcpy() and refreshing only PFN-dependent fields in the destination
> page.
> 
> Tested on a v7.4-rc2 base with 4K base pages and 64 boot-time 1G
> hugepages, measured with a temporary jiffies-based printk.  HVO is
> unavailable on arm64; on x86-64, hugetlb_free_vmemmap=off was used to
> exercise the fallback path.
> 
>   arch    base      with this patch  reduction
>   arm64   360.8 ms  256.0 ms         29.05%
>   x86-64  171.0 ms  165.0 ms          3.51%

Thanks for the numbers!
 
The changes are fine, but since they are going to be merged into Muchun's
series, I'll wait for that for the detailed review.

> Li Zhe (2):
>   mm/mm_init: factor out memmap_init_refresh_pfn_fields()
>   mm/hugetlb: optimize bootmem hugepage tail vmemmap init
> 
>  mm/hugetlb.c | 23 ++++++++++++++++++-----
>  mm/mm_init.c | 11 ++++++-----
>  mm/mm_init.h | 11 +++++++++++
>  3 files changed, 35 insertions(+), 10 deletions(-)

-- 
Sincerely yours,
Mike.