At 11/28/2012 05:40 PM, Jianguo Wu Wrote: > Hi Congyang, > > I think vmemmap's pgtable pages should be freed after all entries are > cleared, I have a patch to do this. > The code logic is the same as [Patch v4 09/12] memory-hotplug: remove page > table of x86_64 architecture. > > How do you think about this? > > Signed-off-by: Jianguo Wu <wujian...@huawei.com> > Signed-off-by: Jiang Liu <jiang....@huawei.com> > --- > include/linux/mm.h | 1 + > mm/sparse-vmemmap.c | 214 > +++++++++++++++++++++++++++++++++++++++++++++++++++ > mm/sparse.c | 5 +- > 3 files changed, 218 insertions(+), 2 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 5657670..1f26af5 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1642,6 +1642,7 @@ int vmemmap_populate(struct page *start_page, unsigned > long pages, int node); > void vmemmap_populate_print_last(void); > void register_page_bootmem_memmap(unsigned long section_nr, struct page *map, > unsigned long size); > +void vmemmap_free(struct page *memmap, unsigned long nr_pages); > > enum mf_flags { > MF_COUNT_INCREASED = 1 << 0, > diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c > index 1b7e22a..242cb28 100644 > --- a/mm/sparse-vmemmap.c > +++ b/mm/sparse-vmemmap.c > @@ -29,6 +29,10 @@ > #include <asm/pgalloc.h> > #include <asm/pgtable.h> > > +#ifdef CONFIG_MEMORY_HOTREMOVE > +#include <asm/tlbflush.h> > +#endif > + > /* > * Allocate a block of memory to be used to back the virtual memory map > * or to back the page tables that are used to create the mapping. > @@ -224,3 +228,213 @@ void __init sparse_mem_maps_populate_node(struct page > **map_map, > vmemmap_buf_end = NULL; > } > } > + > +#ifdef CONFIG_MEMORY_HOTREMOVE > +static void vmemmap_free_pages(struct page *page, int order) > +{ > + struct zone *zone; > + unsigned long magic; > + > + magic = (unsigned long) page->lru.next; > + if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) { > + put_page_bootmem(page); > + > + zone = page_zone(page); > + zone_span_writelock(zone); > + zone->present_pages++; > + zone_span_writeunlock(zone); > + totalram_pages++; > + } else { > + if (is_vmalloc_addr(page_address(page))) > + vfree(page_address(page));
Hmm, vmemmap doesn't use vmalloc() to allocate memory. > + else > + free_pages((unsigned long)page_address(page), order); > + } > +} > + > +static void free_pte_table(pmd_t *pmd) > +{ > + pte_t *pte, *pte_start; > + int i; > + > + pte_start = (pte_t *)pmd_page_vaddr(*pmd); > + for (i = 0; i < PTRS_PER_PTE; i++) { > + pte = pte_start + i; > + if (pte_val(*pte)) > + return; > + } > + > + /* free a pte talbe */ > + vmemmap_free_pages(pmd_page(*pmd), 0); > + spin_lock(&init_mm.page_table_lock); > + pmd_clear(pmd); > + spin_unlock(&init_mm.page_table_lock); > +} > + > +static void free_pmd_table(pud_t *pud) > +{ > + pmd_t *pmd, *pmd_start; > + int i; > + > + pmd_start = (pmd_t *)pud_page_vaddr(*pud); > + for (i = 0; i < PTRS_PER_PMD; i++) { > + pmd = pmd_start + i; > + if (pmd_val(*pmd)) > + return; > + } > + > + /* free a pmd talbe */ > + vmemmap_free_pages(pud_page(*pud), 0); > + spin_lock(&init_mm.page_table_lock); > + pud_clear(pud); > + spin_unlock(&init_mm.page_table_lock); > +} > + > +static void free_pud_table(pgd_t *pgd) > +{ > + pud_t *pud, *pud_start; > + int i; > + > + pud_start = (pud_t *)pgd_page_vaddr(*pgd); > + for (i = 0; i < PTRS_PER_PUD; i++) { > + pud = pud_start + i; > + if (pud_val(*pud)) > + return; > + } > + > + /* free a pud table */ > + vmemmap_free_pages(pgd_page(*pgd), 0); > + spin_lock(&init_mm.page_table_lock); > + pgd_clear(pgd); > + spin_unlock(&init_mm.page_table_lock); > +} > + > +static int split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase) > +{ > + struct page *page = pmd_page(*(pmd_t *)kpte); > + int i = 0; > + unsigned long magic; > + unsigned long section_nr; > + > + __split_large_page(kpte, address, pbase); > + __flush_tlb_all(); > + > + magic = (unsigned long) page->lru.next; > + if (magic == SECTION_INFO) { > + section_nr = pfn_to_section_nr(page_to_pfn(page)); > + while (i < PTRS_PER_PMD) { > + page++; > + i++; > + get_page_bootmem(section_nr, page, SECTION_INFO); > + } > + } > + > + return 0; > +} > + > +static void vmemmap_pte_remove(pmd_t *pmd, unsigned long addr, unsigned long > end) > +{ > + pte_t *pte; > + unsigned long next; > + > + pte = pte_offset_kernel(pmd, addr); > + for (; addr < end; pte++, addr += PAGE_SIZE) { > + next = (addr + PAGE_SIZE) & PAGE_MASK; > + if (next > end) > + next = end; > + > + if (pte_none(*pte)) > + continue; > + if (IS_ALIGNED(addr, PAGE_SIZE) && > + IS_ALIGNED(end, PAGE_SIZE)) { > + vmemmap_free_pages(pte_page(*pte), 0); > + spin_lock(&init_mm.page_table_lock); > + pte_clear(&init_mm, addr, pte); > + spin_unlock(&init_mm.page_table_lock); If addr or end is not alianed with PAGE_SIZE, you may leak some memory. > + } > + } > + > + free_pte_table(pmd); > + __flush_tlb_all(); > +} > + > +static void vmemmap_pmd_remove(pud_t *pud, unsigned long addr, unsigned long > end) > +{ > + unsigned long next; > + pmd_t *pmd; > + > + pmd = pmd_offset(pud, addr); > + for (; addr < end; addr = next, pmd++) { > + next = pmd_addr_end(addr, end); > + if (pmd_none(*pmd)) > + continue; > + > + if (cpu_has_pse) { > + unsigned long pte_base; > + > + if (IS_ALIGNED(addr, PMD_SIZE) && > + IS_ALIGNED(next, PMD_SIZE)) { > + vmemmap_free_pages(pmd_page(*pmd), > + get_order(PMD_SIZE)); > + spin_lock(&init_mm.page_table_lock); > + pmd_clear(pmd); > + spin_unlock(&init_mm.page_table_lock); > + continue; > + } > + > + /* > + * We use 2M page, but we need to remove part of them, > + * so split 2M page to 4K page. > + */ > + pte_base = get_zeroed_page(GFP_ATOMIC | __GFP_NOTRACK); get_zeored_page() may fail. You should handle this error. > + split_large_page((pte_t *)pmd, addr, (pte_t *)pte_base); > + __flush_tlb_all(); > + > + spin_lock(&init_mm.page_table_lock); > + pmd_populate_kernel(&init_mm, pmd, (pte_t *)pte_base); > + spin_unlock(&init_mm.page_table_lock); > + } > + > + vmemmap_pte_remove(pmd, addr, next); > + } > + > + free_pmd_table(pud); > + __flush_tlb_all(); > +} > + > +static void vmemmap_pud_remove(pgd_t *pgd, unsigned long addr, unsigned long > end) > +{ > + unsigned long next; > + pud_t *pud; > + > + pud = pud_offset(pgd, addr); > + for (; addr < end; addr = next, pud++) { > + next = pud_addr_end(addr, end); > + if (pud_none(*pud)) > + continue; > + > + vmemmap_pmd_remove(pud, addr, next); > + } > + > + free_pud_table(pgd); > + __flush_tlb_all(); > +} > + > +void vmemmap_free(struct page *memmap, unsigned long nr_pages) > +{ > + unsigned long addr = (unsigned long)memmap; > + unsigned long end = (unsigned long)(memmap + nr_pages); > + unsigned long next; > + > + for (; addr < end; addr = next) { > + pgd_t *pgd = pgd_offset_k(addr); > + > + next = pgd_addr_end(addr, end); > + if (!pgd_present(*pgd)) > + continue; > + > + vmemmap_pud_remove(pgd, addr, next); > + sync_global_pgds(addr, next); The parameter for sync_global_pgds() is [start, end], not [start, end) > + } > +} > +#endif > diff --git a/mm/sparse.c b/mm/sparse.c > index fac95f2..3a16d68 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -613,12 +613,13 @@ static inline struct page > *kmalloc_section_memmap(unsigned long pnum, int nid, > /* This will make the necessary allocations eventually. */ > return sparse_mem_map_populate(pnum, nid); > } > -static void __kfree_section_memmap(struct page *memmap, unsigned long > nr_pages) > +static void __kfree_section_memmap(struct page *page, unsigned long nr_pages) Why do you change this line? > { > - return; /* XXX: Not implemented yet */ > + vmemmap_free(page, nr_pages); > } > static void free_map_bootmem(struct page *page, unsigned long nr_pages) > { > + vmemmap_free(page, nr_pages); > } > #else > static struct page *__kmalloc_section_memmap(unsigned long nr_pages) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/