Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756717Ab2JECfZ (ORCPT ); Thu, 4 Oct 2012 22:35:25 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:59113 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756511Ab2JECfU (ORCPT ); Thu, 4 Oct 2012 22:35:20 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <506E4741.6080402@jp.fujitsu.com> Date: Fri, 5 Oct 2012 11:34:41 +0900 From: Yasuaki Ishimatsu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:15.0) Gecko/20120907 Thunderbird/15.0.1 MIME-Version: 1.0 To: , , , , , , , , , CC: Yasuaki Ishimatsu , , , , , , , , Subject: [PATCH 7/10] memory-hotplug : remove memmap of sparse-vmemmap References: <506E43E0.70507@jp.fujitsu.com> In-Reply-To: <506E43E0.70507@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9850 Lines: 317 All pages of virtual mapping in removed memory cannot be freed, since some pages used as PGD/PUD includes not only removed memory but also other memory. So the patch checks whether page can be freed or not. How to check whether page can be freed or not? 1. When removing memory, the page structs of the revmoved memory are filled with 0FD. 2. All page structs are filled with 0xFD on PT/PMD, PT/PMD can be cleared. In this case, the page used as PT/PMD can be freed. Applying patch, __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is integrated into one. So __remove_section() of CONFIG_SPARSEMEM_VMEMMAP is deleted. Note: vmemmap_kfree() and vmemmap_free_bootmem() are not implemented for ia64, ppc, s390, and sparc. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Wen Congyang Signed-off-by: Yasuaki Ishimatsu --- arch/ia64/mm/discontig.c | 8 +++ arch/powerpc/mm/init_64.c | 8 +++ arch/s390/mm/vmem.c | 8 +++ arch/sparc/mm/init_64.c | 8 +++ arch/x86/mm/init_64.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/mm.h | 2 mm/memory_hotplug.c | 17 ------ mm/sparse.c | 5 + 8 files changed, 158 insertions(+), 17 deletions(-) Index: linux-3.6/arch/ia64/mm/discontig.c =================================================================== --- linux-3.6.orig/arch/ia64/mm/discontig.c 2012-10-04 18:30:15.475692638 +0900 +++ linux-3.6/arch/ia64/mm/discontig.c 2012-10-04 18:30:21.145698389 +0900 @@ -823,6 +823,14 @@ int __meminit vmemmap_populate(struct pa return vmemmap_populate_basepages(start_page, size, node); } +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages) +{ +} + +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages) +{ +} + void register_page_bootmem_memmap(unsigned long section_nr, struct page *start_page, unsigned long size) { Index: linux-3.6/arch/powerpc/mm/init_64.c =================================================================== --- linux-3.6.orig/arch/powerpc/mm/init_64.c 2012-10-04 18:30:15.494692657 +0900 +++ linux-3.6/arch/powerpc/mm/init_64.c 2012-10-04 18:30:21.150698394 +0900 @@ -299,6 +299,14 @@ int __meminit vmemmap_populate(struct pa return 0; } +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages) +{ +} + +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages) +{ +} + void register_page_bootmem_memmap(unsigned long section_nr, struct page *start_page, unsigned long size) { Index: linux-3.6/arch/s390/mm/vmem.c =================================================================== --- linux-3.6.orig/arch/s390/mm/vmem.c 2012-10-04 18:30:15.506692670 +0900 +++ linux-3.6/arch/s390/mm/vmem.c 2012-10-04 18:30:21.157698401 +0900 @@ -227,6 +227,14 @@ out: return ret; } +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages) +{ +} + +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages) +{ +} + void register_page_bootmem_memmap(unsigned long section_nr, struct page *start_page, unsigned long size) { Index: linux-3.6/arch/sparc/mm/init_64.c =================================================================== --- linux-3.6.orig/arch/sparc/mm/init_64.c 2012-10-04 18:30:15.512692676 +0900 +++ linux-3.6/arch/sparc/mm/init_64.c 2012-10-04 18:30:21.163698408 +0900 @@ -2078,6 +2078,14 @@ void __meminit vmemmap_populate_print_la } } +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages) +{ +} + +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages) +{ +} + void register_page_bootmem_memmap(unsigned long section_nr, struct page *start_page, unsigned long size) { Index: linux-3.6/arch/x86/mm/init_64.c =================================================================== --- linux-3.6.orig/arch/x86/mm/init_64.c 2012-10-04 18:30:15.517692681 +0900 +++ linux-3.6/arch/x86/mm/init_64.c 2012-10-04 18:30:21.171698416 +0900 @@ -993,6 +993,125 @@ vmemmap_populate(struct page *start_page return 0; } +#define PAGE_INUSE 0xFD + +unsigned long find_and_clear_pte_page(unsigned long addr, unsigned long end, + struct page **pp, int *page_size) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + void *page_addr; + unsigned long next; + + *pp = NULL; + + pgd = pgd_offset_k(addr); + if (pgd_none(*pgd)) + return pgd_addr_end(addr, end); + + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) + return pud_addr_end(addr, end); + + if (!cpu_has_pse) { + next = (addr + PAGE_SIZE) & PAGE_MASK; + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return next; + + pte = pte_offset_kernel(pmd, addr); + if (pte_none(*pte)) + return next; + + *page_size = PAGE_SIZE; + *pp = pte_page(*pte); + } else { + next = pmd_addr_end(addr, end); + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) + return next; + + *page_size = PMD_SIZE; + *pp = pmd_page(*pmd); + } + + /* + * Removed page structs are filled with 0xFD. + */ + memset((void *)addr, PAGE_INUSE, next - addr); + + page_addr = page_address(*pp); + + /* + * Check the page is filled with 0xFD or not. + * memchr_inv() returns the address. In this case, we cannot + * clear PTE/PUD entry, since the page is used by other. + * So we cannot also free the page. + * + * memchr_inv() returns NULL. In this case, we can clear + * PTE/PUD entry, since the page is not used by other. + * So we can also free the page. + */ + if (memchr_inv(page_addr, PAGE_INUSE, *page_size)) { + *pp = NULL; + return next; + } + + if (!cpu_has_pse) + pte_clear(&init_mm, addr, pte); + else + pmd_clear(pmd); + + return next; +} + +void vmemmap_kfree(struct page *memmap, unsigned long nr_pages) +{ + unsigned long addr = (unsigned long)memmap; + unsigned long end = (unsigned long)(memmap + nr_pages); + unsigned long next; + struct page *page; + int page_size; + + for (; addr < end; addr = next) { + page = NULL; + page_size = 0; + next = find_and_clear_pte_page(addr, end, &page, &page_size); + if (!page) + continue; + + free_pages((unsigned long)page_address(page), + get_order(page_size)); + __flush_tlb_one(addr); + } +} + +void vmemmap_free_bootmem(struct page *memmap, unsigned long nr_pages) +{ + unsigned long addr = (unsigned long)memmap; + unsigned long end = (unsigned long)(memmap + nr_pages); + unsigned long next; + struct page *page; + int page_size; + unsigned long magic; + + for (; addr < end; addr = next) { + page = NULL; + page_size = 0; + next = find_and_clear_pte_page(addr, end, &page, &page_size); + if (!page) + continue; + + magic = (unsigned long) page->lru.next; + if (magic == SECTION_INFO) + put_page_bootmem(page); + flush_tlb_kernel_range(addr, end); + } +} + void register_page_bootmem_memmap(unsigned long section_nr, struct page *start_page, unsigned long size) { Index: linux-3.6/include/linux/mm.h =================================================================== --- linux-3.6.orig/include/linux/mm.h 2012-10-04 18:30:15.524692688 +0900 +++ linux-3.6/include/linux/mm.h 2012-10-04 18:30:21.177698422 +0900 @@ -1620,6 +1620,8 @@ int vmemmap_populate(struct page *start_ void vmemmap_populate_print_last(void); void register_page_bootmem_memmap(unsigned long section_nr, struct page *map, unsigned long size); +void vmemmap_kfree(struct page *memmpa, unsigned long nr_pages); +void vmemmap_free_bootmem(struct page *memmpa, unsigned long nr_pages); enum mf_flags { MF_COUNT_INCREASED = 1 << 0, Index: linux-3.6/mm/memory_hotplug.c =================================================================== --- linux-3.6.orig/mm/memory_hotplug.c 2012-10-04 18:30:15.464692627 +0900 +++ linux-3.6/mm/memory_hotplug.c 2012-10-04 18:30:21.182698427 +0900 @@ -312,19 +312,6 @@ static int __meminit __add_section(int n return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); } -#ifdef CONFIG_SPARSEMEM_VMEMMAP -static int __remove_section(struct zone *zone, struct mem_section *ms) -{ - int ret = -EINVAL; - - if (!valid_section(ms)) - return ret; - - ret = unregister_memory_section(ms); - - return ret; -} -#else static int __remove_section(struct zone *zone, struct mem_section *ms) { unsigned long flags; @@ -341,9 +328,9 @@ static int __remove_section(struct zone pgdat_resize_lock(pgdat, &flags); sparse_remove_one_section(zone, ms); pgdat_resize_unlock(pgdat, &flags); - return 0; + + return ret; } -#endif /* * Reasonably generic function for adding memory. It is Index: linux-3.6/mm/sparse.c =================================================================== --- linux-3.6.orig/mm/sparse.c 2012-10-04 18:26:53.908488966 +0900 +++ linux-3.6/mm/sparse.c 2012-10-04 18:30:21.185698430 +0900 @@ -613,12 +613,13 @@ static inline struct page *kmalloc_secti /* 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) { - return; /* XXX: Not implemented yet */ + vmemmap_kfree(page, nr_pages); } static void free_map_bootmem(struct page *page, unsigned long nr_pages) { + vmemmap_free_bootmem(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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/