diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ee9cbaaa63f4..cd68c1904c91 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -2143,11 +2143,21 @@ static inline int online_device_section(const struct mem_section *section) return section && ((section->section_mem_map & flags) == flags); } + +static inline struct zone *device_zone(int nid) +{ + return &NODE_DATA(nid)->node_zones[ZONE_DEVICE]; +} #else static inline int online_device_section(const struct mem_section *section) { return 0; } + +static inline struct zone *device_zone(int nid) +{ + return NULL; +} #endif static inline int online_section_nr(unsigned long nr) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b428da66d279..d7a59167bec4 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -43,6 +43,7 @@ #include "mm_init.h" #include "page_alloc.h" #include "shuffle.h" +#include "sparse.h" enum { MEMMAP_ON_MEMORY_DISABLE = 0, @@ -554,8 +555,9 @@ void remove_pfn_range_from_zone(struct zone *zone, /* Select all remaining pages up to the next section boundary */ cur_nr_pages = min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn); - page_init_poison(pfn_to_page(pfn), - sizeof(struct page) * cur_nr_pages); + if (!section_vmemmap_optimizable(__pfn_to_section(pfn))) + page_init_poison(pfn_to_page(pfn), + sizeof(struct page) * cur_nr_pages); } /* diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 26be355aaa37..060342ac4882 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -224,6 +224,8 @@ struct page __ref *vmemmap_shared_tail_page(unsigned int order, struct zone *zon atomic_set(&page->_mapcount, -1); set_page_node(page, zone_to_nid(zone)); set_page_zone(page, zone_idx(zone)); + if (zone_is_zone_device(zone)) + __SetPageReserved(page); prep_compound_tail(page, NULL, order); } @@ -288,14 +290,18 @@ static pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, in /* * When a PTE/PMD entry is freed from the init_mm * there's a free_pages() call to this page allocated - * above. Thus this get_page() is paired with the + * above. Thus this try_get_page() is paired with the * put_page_testzero() on the freeing path. * This can only called by certain ZONE_DEVICE path, * and through vmemmap_populate_compound_pages() when * slab is available. + * + * Use try_get_page() to prevent the shared page refcount + * from overflowing. */ - if (flags & VMEMMAP_POPULATE_DAX) - get_page(pfn_to_page(ptpfn)); + if ((flags & VMEMMAP_POPULATE_DAX) && + !try_get_page(pfn_to_page(ptpfn))) + return NULL; } entry = pfn_pte(ptpfn, PAGE_KERNEL); set_pte_at(&init_mm, addr, pte, entry); @@ -529,47 +535,27 @@ static bool __meminit reuse_compound_section(unsigned long start_pfn, return !IS_ALIGNED(offset, nr_pages) && nr_pages > PAGES_PER_SUBSECTION; } -static pte_t * __meminit compound_section_tail_page(unsigned long addr) -{ - pte_t *pte; - - addr -= PAGE_SIZE; - - /* - * Assuming sections are populated sequentially, the previous section's - * page data can be reused. - */ - pte = pte_offset_kernel(pmd_off_k(addr), addr); - if (!pte) - return NULL; - - return pte; -} - static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, unsigned long start, unsigned long end, int node, struct dev_pagemap *pgmap) { const unsigned long flags = VMEMMAP_POPULATE_DAX; + const unsigned int order = pfn_to_section_compound_order(start_pfn); unsigned long size, addr; pte_t *pte; + struct page *page; int rc; - if (reuse_compound_section(start_pfn, pgmap)) { - pte = compound_section_tail_page(start); - if (!pte) - return -ENOMEM; + page = vmemmap_shared_tail_page(order, device_zone(node)); + if (!page) + return -ENOMEM; - /* - * Reuse the page that was populated in the prior iteration - * with just tail struct pages. - */ + if (reuse_compound_section(start_pfn, pgmap)) return vmemmap_populate_range(start, end, node, NULL, - pte_pfn(ptep_get(pte)), flags); - } + page_to_pfn(page), flags); - size = min(end - start, pgmap_vmemmap_nr(pgmap) * sizeof(struct page)); + size = min(end - start, (1UL << order) * sizeof(struct page)); for (addr = start; addr < end; addr += size) { unsigned long next, last = addr + size; @@ -585,12 +571,12 @@ static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, return -ENOMEM; /* - * Reuse the previous page for the rest of tail pages + * Reuse the shared page for the rest of tail pages * See layout diagram in Documentation/mm/vmemmap_dedup.rst */ next += PAGE_SIZE; rc = vmemmap_populate_range(next, last, node, NULL, - pte_pfn(ptep_get(pte)), flags); + page_to_pfn(page), flags); if (rc) return -ENOMEM; } @@ -922,13 +908,16 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, if (IS_ERR(memmap)) return PTR_ERR(memmap); - /* - * Poison uninitialized struct pages in order to catch invalid flags - * combinations. - */ - page_init_poison(memmap, sizeof(struct page) * nr_pages); - ms = __nr_to_section(section_nr); + /* + * Poison uninitialized struct pages to catch invalid flag combinations. + * + * Tail struct pages in a vmemmap-optimized section are initialized and + * shared during vmemmap population, so they must not be overwritten here. + */ + if (!section_vmemmap_optimizable(ms)) + page_init_poison(memmap, sizeof(struct page) * nr_pages); + __section_mark_present(ms, section_nr); /* Align memmap to section boundary in the subsection case */