Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751758Ab2JVHsY (ORCPT ); Mon, 22 Oct 2012 03:48:24 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:24575 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751555Ab2JVHsU (ORCPT ); Mon, 22 Oct 2012 03:48:20 -0400 X-IronPort-AV: E=Sophos;i="4.80,628,1344182400"; d="scan'208";a="6043034" Message-ID: <5084F195.6030908@cn.fujitsu.com> Date: Mon, 22 Oct 2012 15:11:17 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: wujianguo CC: Yasuaki Ishimatsu , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, cl@linux.com, minchan.kim@gmail.com, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, wujianguo@huawei.com, qiuxishi@huawei.com, jiang.liu@huawei.com Subject: Re: [PATCH 8/10] memory-hotplug : remove page table of x86_64 architecture References: <506E43E0.70507@jp.fujitsu.com> <506E4799.30407@jp.fujitsu.com> <5073DFC0.3010400@gmail.com> In-Reply-To: <5073DFC0.3010400@gmail.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/22 15:05:12, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/22 15:06:04, Serialize complete at 2012/10/22 15:06:04 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 14827 Lines: 524 Hi, Wu Sorry for late reply. At 10/09/2012 04:26 PM, wujianguo Wrote: > Hi Congyang, > I think we should also free pages which are used by page tables after removing > page tables of the memory. It is OK to do it. > > From: Jianguo Wu > > Signed-off-by: Jianguo Wu > Signed-off-by: Jiang Liu > --- > arch/x86/mm/init_64.c | 110 +++++++++++++++++++++++++++++++++++++++--------- > 1 files changed, 89 insertions(+), 21 deletions(-) > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 5596dfa..81f9c3b 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -675,6 +675,74 @@ int arch_add_memory(int nid, u64 start, u64 size) > } > EXPORT_SYMBOL_GPL(arch_add_memory); > > +static inline void free_pagetable(struct page *page) > +{ > + struct zone *zone; > + > + __ClearPageReserved(page); > + __free_page(page); > + > + zone = page_zone(page); > + zone_span_writelock(zone); > + zone->present_pages++; > + zone_span_writeunlock(zone); > + totalram_pages++; Why do you update zone and totalram_pages here? > +} > + > +static void free_pte_table(pte_t *pte_start, pmd_t *pmd) > +{ > + pte_t *pte; > + int i; > + > + for (i = 0; i < PTRS_PER_PTE; i++) { > + pte = pte_start + i; > + if (pte_val(*pte)) > + break; > + } > + > + /* free a pte talbe */ > + if (i == PTRS_PER_PTE) { > + free_pagetable(pmd_page(*pmd)); The memory may be allocated at booting. So it is very dangerous to free it without any check. > + pmd_clear(pmd); > + } > +} > + > +static void free_pmd_table(pmd_t *pmd_start, pud_t *pud) > +{ > + pmd_t *pmd; > + int i; > + > + for (i = 0; i < PTRS_PER_PMD; i++) { > + pmd = pmd_start + i; > + if (pmd_val(*pmd)) > + break; > + } > + > + /* free a pmd talbe */ > + if (i == PTRS_PER_PMD) { > + free_pagetable(pud_page(*pud)); > + pud_clear(pud); > + } > +} > + > +static void free_pud_table(pud_t *pud_start, pgd_t *pgd) > +{ > + pud_t *pud; > + int i; > + > + for (i = 0; i < PTRS_PER_PUD; i++) { > + pud = pud_start + i; > + if (pud_val(*pud)) > + break; > + } > + > + /* free a pud table */ > + if (i == PTRS_PER_PUD) { > + free_pagetable(pgd_page(*pgd)); > + pgd_clear(pgd); > + } > +} > + > static void __meminit > phys_pte_remove(pte_t *pte_page, unsigned long addr, unsigned long end) > { > @@ -704,21 +772,19 @@ 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) { > + for (; i < PTRS_PER_PMD && addr < end; 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; > + next = pmd_addr_end(addr, end); > > if (!pmd_present(*pmd)) > continue; > > if (pmd_large(*pmd)) { > - if ((addr & ~PMD_MASK) == 0 && next <= end) { > + if (IS_ALIGNED(addr, PMD_SIZE) && > + IS_ALIGNED(next, PMD_SIZE)) { > set_pmd(pmd, __pmd(0)); > pages++; > continue; > @@ -729,7 +795,8 @@ phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) > * so split 2M page to 4K page. > */ > pte = alloc_low_page(&pte_phys); > - __split_large_page((pte_t *)pmd, addr, pte); > + __split_large_page((pte_t *)pmd, > + (unsigned long)__va(addr), pte); > > spin_lock(&init_mm.page_table_lock); > pmd_populate_kernel(&init_mm, pmd, __va(pte_phys)); > @@ -738,7 +805,8 @@ phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) > > spin_lock(&init_mm.page_table_lock); > pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd)); > - phys_pte_remove(pte, addr, end); > + phys_pte_remove(pte, addr, next); > + free_pte_table(pte, pmd); > unmap_low_page(pte); > spin_unlock(&init_mm.page_table_lock); > } > @@ -751,21 +819,19 @@ 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) { > + for (; i < PTRS_PER_PUD && addr < end; 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; > + next = pud_addr_end(addr, end); > > if (!pud_present(*pud)) > continue; > > if (pud_large(*pud)) { > - if ((addr & ~PUD_MASK) == 0 && next <= end) { > + if (IS_ALIGNED(addr, PUD_SIZE) && > + IS_ALIGNED(next, PUD_SIZE)) { > set_pud(pud, __pud(0)); > pages++; > continue; > @@ -776,15 +842,18 @@ phys_pud_remove(pud_t *pud_page, unsigned long addr, unsigned long end) > * so split 1G page to 2M page. > */ > pmd = alloc_low_page(&pmd_phys); > - __split_large_page((pte_t *)pud, addr, (pte_t *)pmd); > + __split_large_page((pte_t *)pud, > + (unsigned long)__va(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); > + pmd = map_low_page((pmd_t *)pud_page_vaddr(*pud)); Hmm, pmd_offset(pud, 0) is equal to (pmd_t *)pud_page_vaddr(*pud). Is it OK to merge your patch into my patch? Thanks Wen Congyang > + phys_pmd_remove(pmd, addr, next); > + free_pmd_table(pmd, pud); > unmap_low_page(pmd); > __flush_tlb_all(); > } > @@ -805,15 +874,14 @@ kernel_physical_mapping_remove(unsigned long start, unsigned long end) > pgd_t *pgd = pgd_offset_k(start); > pud_t *pud; > > - next = (start + PGDIR_SIZE) & PGDIR_MASK; > - if (next > end) > - next = end; > + next = pgd_addr_end(start, end); > > if (!pgd_present(*pgd)) > continue; > > pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd)); > - phys_pud_remove(pud, __pa(start), __pa(end)); > + phys_pud_remove(pud, __pa(start), __pa(next)); > + free_pud_table(pud, pgd); > unmap_low_page(pud); > } > > -- 1.7.6.1 . > > > On 2012-10-5 10:36, Yasuaki Ishimatsu wrote: >> 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, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@kvack.org. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: email@kvack.org >> > > -- 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/