This series moves the boot time initialization of tail struct pages of a gigantic page to later on in the boot. Only the HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page) - 1 tail struct pages are initialized at the start. If HVO is successful, then no more tail struct pages need to be initialized. For a 1G hugepage, this series avoid initialization of 262144 - 63 = 262081 struct pages per hugepage. When tested on a 512G system (allocating 500 1G hugepages), the kexec-boot times with DEFERRED_STRUCT_PAGE_INIT enabled are: - with patches, HVO enabled: 1.32 seconds - with patches, HVO disabled: 2.15 seconds - without patches, HVO enabled: 3.90 seconds - without patches, HVO disabled: 3.58 seconds This represents an approximately 70% reduction in boot time and will significantly reduce server downtime when using a large number of gigantic pages. Usama Arif (4): mm: hugetlb_vmemmap: use nid of the head page to reallocate it memblock: pass memblock_type to memblock_setclr_flag memblock: introduce MEMBLOCK_RSRV_NOINIT flag mm: hugetlb: skip initialization of gigantic tail struct pages if freed by HVO include/linux/memblock.h | 9 ++++++ mm/hugetlb.c | 68 ++++++++++++++++++++++++++++++++++------ mm/hugetlb_vmemmap.c | 4 +-- mm/hugetlb_vmemmap.h | 9 +++--- mm/internal.h | 3 ++ mm/memblock.c | 49 +++++++++++++++++++++-------- mm/mm_init.c | 2 +- 7 files changed, 115 insertions(+), 29 deletions(-) -- 2.25.1