Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756734Ab2JECgo (ORCPT ); Thu, 4 Oct 2012 22:36:44 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:48147 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756511Ab2JECgl (ORCPT ); Thu, 4 Oct 2012 22:36:41 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <506E4799.30407@jp.fujitsu.com> Date: Fri, 5 Oct 2012 11:36:09 +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 8/10] memory-hotplug : remove page table of x86_64 architecture 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: 7551 Lines: 284 From: Wen Congyang For hot removing memory, we sholud remove page table about the memory. So the patch searches a page table about the removed memory, and clear page table. CC: David Rientjes CC: Jiang Liu CC: Len Brown CC: Christoph Lameter Cc: Minchan Kim CC: Andrew Morton CC: KOSAKI Motohiro CC: Yasuaki Ishimatsu Signed-off-by: Wen Congyang --- arch/x86/include/asm/pgtable_types.h | 1 arch/x86/mm/init_64.c | 147 +++++++++++++++++++++++++++++++++++ arch/x86/mm/pageattr.c | 47 +++++------ 3 files changed, 173 insertions(+), 22 deletions(-) Index: linux-3.6/arch/x86/mm/init_64.c =================================================================== --- linux-3.6.orig/arch/x86/mm/init_64.c 2012-10-04 18:30:21.171698416 +0900 +++ linux-3.6/arch/x86/mm/init_64.c 2012-10-04 18:30:27.317704652 +0900 @@ -675,6 +675,151 @@ int arch_add_memory(int nid, u64 start, } EXPORT_SYMBOL_GPL(arch_add_memory); +static void __meminit +phys_pte_remove(pte_t *pte_page, unsigned long addr, unsigned long end) +{ + unsigned pages = 0; + int i = pte_index(addr); + + pte_t *pte = pte_page + pte_index(addr); + + for (; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE, pte++) { + + if (addr >= end) + break; + + if (!pte_present(*pte)) + continue; + + pages++; + set_pte(pte, __pte(0)); + } + + update_page_count(PG_LEVEL_4K, -pages); +} + +static void __meminit +phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) +{ + unsigned long pages = 0, next; + int i = pmd_index(addr); + + for (; i < PTRS_PER_PMD; i++, addr = next) { + unsigned long pte_phys; + pmd_t *pmd = pmd_page + pmd_index(addr); + pte_t *pte; + + if (addr >= end) + break; + + next = (addr & PMD_MASK) + PMD_SIZE; + + if (!pmd_present(*pmd)) + continue; + + if (pmd_large(*pmd)) { + if ((addr & ~PMD_MASK) == 0 && next <= end) { + set_pmd(pmd, __pmd(0)); + pages++; + continue; + } + + /* + * We use 2M page, but we need to remove part of them, + * so split 2M page to 4K page. + */ + pte = alloc_low_page(&pte_phys); + __split_large_page((pte_t *)pmd, addr, pte); + + spin_lock(&init_mm.page_table_lock); + pmd_populate_kernel(&init_mm, pmd, __va(pte_phys)); + spin_unlock(&init_mm.page_table_lock); + } + + spin_lock(&init_mm.page_table_lock); + pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd)); + phys_pte_remove(pte, addr, end); + unmap_low_page(pte); + spin_unlock(&init_mm.page_table_lock); + } + update_page_count(PG_LEVEL_2M, -pages); +} + +static void __meminit +phys_pud_remove(pud_t *pud_page, unsigned long addr, unsigned long end) +{ + unsigned long pages = 0, next; + int i = pud_index(addr); + + for (; i < PTRS_PER_PUD; i++, addr = next) { + unsigned long pmd_phys; + pud_t *pud = pud_page + pud_index(addr); + pmd_t *pmd; + + if (addr >= end) + break; + + next = (addr & PUD_MASK) + PUD_SIZE; + + if (!pud_present(*pud)) + continue; + + if (pud_large(*pud)) { + if ((addr & ~PUD_MASK) == 0 && next <= end) { + set_pud(pud, __pud(0)); + pages++; + continue; + } + + /* + * We use 1G page, but we need to remove part of them, + * so split 1G page to 2M page. + */ + pmd = alloc_low_page(&pmd_phys); + __split_large_page((pte_t *)pud, addr, (pte_t *)pmd); + + spin_lock(&init_mm.page_table_lock); + pud_populate(&init_mm, pud, __va(pmd_phys)); + spin_unlock(&init_mm.page_table_lock); + } + + pmd = map_low_page(pmd_offset(pud, 0)); + phys_pmd_remove(pmd, addr, end); + unmap_low_page(pmd); + __flush_tlb_all(); + } + __flush_tlb_all(); + + update_page_count(PG_LEVEL_1G, -pages); +} + +void __meminit +kernel_physical_mapping_remove(unsigned long start, unsigned long end) +{ + unsigned long next; + + start = (unsigned long)__va(start); + end = (unsigned long)__va(end); + + for (; start < end; start = next) { + pgd_t *pgd = pgd_offset_k(start); + pud_t *pud; + + next = (start + PGDIR_SIZE) & PGDIR_MASK; + if (next > end) + next = end; + + if (!pgd_present(*pgd)) + continue; + + pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd)); + phys_pud_remove(pud, __pa(start), __pa(end)); + unmap_low_page(pud); + } + + __flush_tlb_all(); +} + #ifdef CONFIG_MEMORY_HOTREMOVE int __ref arch_remove_memory(u64 start, u64 size) { @@ -687,6 +832,8 @@ int __ref arch_remove_memory(u64 start, ret = __remove_pages(zone, start_pfn, nr_pages); WARN_ON_ONCE(ret); + kernel_physical_mapping_remove(start, start + size); + return ret; } #endif Index: linux-3.6/arch/x86/include/asm/pgtable_types.h =================================================================== --- linux-3.6.orig/arch/x86/include/asm/pgtable_types.h 2012-10-04 18:26:51.925486954 +0900 +++ linux-3.6/arch/x86/include/asm/pgtable_types.h 2012-10-04 18:30:27.322704656 +0900 @@ -334,6 +334,7 @@ static inline void update_page_count(int * as a pte too. */ extern pte_t *lookup_address(unsigned long address, unsigned int *level); +extern int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase); #endif /* !__ASSEMBLY__ */ Index: linux-3.6/arch/x86/mm/pageattr.c =================================================================== --- linux-3.6.orig/arch/x86/mm/pageattr.c 2012-10-04 18:26:51.923486952 +0900 +++ linux-3.6/arch/x86/mm/pageattr.c 2012-10-04 18:30:27.328704662 +0900 @@ -501,21 +501,13 @@ out_unlock: return do_split; } -static int split_large_page(pte_t *kpte, unsigned long address) +int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase) { unsigned long pfn, pfninc = 1; unsigned int i, level; - pte_t *pbase, *tmp; + pte_t *tmp; pgprot_t ref_prot; - struct page *base; - - if (!debug_pagealloc) - spin_unlock(&cpa_lock); - base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0); - if (!debug_pagealloc) - spin_lock(&cpa_lock); - if (!base) - return -ENOMEM; + struct page *base = virt_to_page(pbase); spin_lock(&pgd_lock); /* @@ -523,10 +515,11 @@ static int split_large_page(pte_t *kpte, * up for us already: */ tmp = lookup_address(address, &level); - if (tmp != kpte) - goto out_unlock; + if (tmp != kpte) { + spin_unlock(&pgd_lock); + return 1; + } - pbase = (pte_t *)page_address(base); paravirt_alloc_pte(&init_mm, page_to_pfn(base)); ref_prot = pte_pgprot(pte_clrhuge(*kpte)); /* @@ -579,17 +572,27 @@ static int split_large_page(pte_t *kpte, * going on. */ __flush_tlb_all(); + spin_unlock(&pgd_lock); - base = NULL; + return 0; +} -out_unlock: - /* - * If we dropped out via the lookup_address check under - * pgd_lock then stick the page back into the pool: - */ - if (base) +static int split_large_page(pte_t *kpte, unsigned long address) +{ + pte_t *pbase; + struct page *base; + + if (!debug_pagealloc) + spin_unlock(&cpa_lock); + base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0); + if (!debug_pagealloc) + spin_lock(&cpa_lock); + if (!base) + return -ENOMEM; + + pbase = (pte_t *)page_address(base); + if (__split_large_page(kpte, address, pbase)) __free_page(base); - spin_unlock(&pgd_lock); return 0; } -- 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/