If we enable the CONFIG_HUGETLB_PAGE_FREE_VMEMMAP, we can just disbale PMD page mapping of vmemmap to simplify the code. In this case, we do not need complex code doing vmemmap page table manipulation. This is a way to simply the first version of this patch series. In the future, we can add some code doing page table manipulation. Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> --- arch/x86/mm/init_64.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 0435bee2e172..155cb06a6961 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1557,7 +1557,9 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, { int err; - if (end - start < PAGES_PER_SECTION * sizeof(struct page)) + if (IS_ENABLED(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP)) + err = vmemmap_populate_basepages(start, end, node, NULL); + else if (end - start < PAGES_PER_SECTION * sizeof(struct page)) err = vmemmap_populate_basepages(start, end, node, NULL); else if (boot_cpu_has(X86_FEATURE_PSE)) err = vmemmap_populate_hugepages(start, end, node, altmap); @@ -1610,7 +1612,8 @@ void register_page_bootmem_memmap(unsigned long section_nr, } get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO); - if (!boot_cpu_has(X86_FEATURE_PSE)) { + if (!boot_cpu_has(X86_FEATURE_PSE) || + IS_ENABLED(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP)) { next = (addr + PAGE_SIZE) & PAGE_MASK; pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) -- 2.11.0