Messages in this thread Patch in this message | | | Date | Tue, 04 Dec 2012 17:13:27 +0800 | From | Tang Chen <> | Subject | Re: [Patch v4 08/12] memory-hotplug: remove memmap of sparse-vmemmap |
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Hi Wu,
Sorry to make noise here. Please see below. :)
On 12/03/2012 10:23 AM, Jianguo Wu wrote: > Signed-off-by: Jianguo Wu<wujianguo@huawei.com> > Signed-off-by: Jiang Liu<jiang.liu@huawei.com> > --- > include/linux/mm.h | 1 + > mm/sparse-vmemmap.c | 231 +++++++++++++++++++++++++++++++++++++++++++++++++++ > mm/sparse.c | 3 +- > 3 files changed, 234 insertions(+), 1 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..748732d 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 +228,230 @@ void __init sparse_mem_maps_populate_node(struct page **map_map, > vmemmap_buf_end = NULL; > } > } > + > +#ifdef CONFIG_MEMORY_HOTREMOVE > + > +#define PAGE_INUSE 0xFD > + > +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++;
Seems that we have different ways to handle pages allocated by bootmem or by regular allocator. Is the checking way in [PATCH 09/12] available here ?
+ /* bootmem page has reserved flag */ + if (PageReserved(page)) { ...... + }
If so, I think we can just merge these two functions.
> + } 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); > +}
All the free_xxx_table() are very similar to the functions in [PATCH 09/12]. Could we reuse them anyway ?
> + > +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);
Is this patch going to replace [PATCH 08/12] ?
If so, __split_large_page() was added and exported in [PATCH 09/12], then we should move it here, right ?
If not, free_map_bootmem() and __kfree_section_memmap() were changed in [PATCH 08/12], and we need to handle this.
> + __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; > + void *page_addr; > + > + 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(next, 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); > + } else { > + /* > + * Removed page structs are filled with 0xFD. > + */ > + memset((void *)addr, PAGE_INUSE, next - addr); > + page_addr = page_address(pte_page(*pte)); > + > + if (!memchr_inv(page_addr, PAGE_INUSE, PAGE_SIZE)) { > + spin_lock(&init_mm.page_table_lock); > + pte_clear(&init_mm, addr, pte); > + spin_unlock(&init_mm.page_table_lock); > + } > + } > + } > + > + 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); > + if (!pte_base) { > + WARN_ON(1); > + continue; > + } > + > + 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 - 1); > + } > +} > +#endif > diff --git a/mm/sparse.c b/mm/sparse.c > index fac95f2..4060229 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -615,10 +615,11 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid, > } > static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages) > { > - return; /* XXX: Not implemented yet */ > + vmemmap_free(memmap, nr_pages); > } > static void free_map_bootmem(struct page *page, unsigned long nr_pages)
In the latest kernel, this line was: static void free_map_bootmem(struct page *memmap, unsigned long nr_pages)
> { > + vmemmap_free(page, nr_pages); > } > #else > static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
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