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Message-ID: <5018C76D.8000205@cn.fujitsu.com>
Date: Wed, 01 Aug 2012 14:06:37 +0800
From: Wen Congyang <wency@...fujitsu.com>
To: jencce zhou <jencce2002@...il.com>
CC: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-acpi@...r.kernel.org,
linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
linux-ia64@...r.kernel.org, cmetcalf@...era.com,
rientjes@...gle.com, liuj97@...il.com, len.brown@...el.com,
benh@...nel.crashing.org, paulus@...ba.org, cl@...ux.com,
minchan.kim@...il.com, akpm@...ux-foundation.org,
kosaki.motohiro@...fujitsu.com,
Yasuaki ISIMATU <isimatu.yasuaki@...fujitsu.com>
Subject: Re: [RFC PATCH v5 12/19] memory-hotplug: introduce new function arch_remove_memory()
At 08/01/2012 10:44 AM, jencce zhou Wrote:
> 2012/7/27 Wen Congyang <wency@...fujitsu.com>:
>> We don't call __add_pages() directly in the function add_memory()
>> because some other architecture related things need to be done
>> before or after calling __add_pages(). So we should introduce
>> a new function arch_remove_memory() to revert the things
>> done in arch_add_memory().
>>
>> Note: the function for s390 is not implemented(I don't know how to
>> implement it for s390).
>>
>> CC: David Rientjes <rientjes@...gle.com>
>> CC: Jiang Liu <liuj97@...il.com>
>> CC: Len Brown <len.brown@...el.com>
>> CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
>> CC: Paul Mackerras <paulus@...ba.org>
>> CC: Christoph Lameter <cl@...ux.com>
>> Cc: Minchan Kim <minchan.kim@...il.com>
>> CC: Andrew Morton <akpm@...ux-foundation.org>
>> CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
>> CC: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@...fujitsu.com>
>> ---
>> arch/ia64/mm/init.c | 16 ++++
>> arch/powerpc/mm/mem.c | 14 +++
>> arch/s390/mm/init.c | 8 ++
>> arch/sh/mm/init.c | 15 +++
>> arch/tile/mm/init.c | 8 ++
>> arch/x86/include/asm/pgtable_types.h | 1 +
>> arch/x86/mm/init_32.c | 10 ++
>> arch/x86/mm/init_64.c | 160 ++++++++++++++++++++++++++++++++++
>> arch/x86/mm/pageattr.c | 47 +++++-----
>> include/linux/memory_hotplug.h | 1 +
>> mm/memory_hotplug.c | 1 +
>> 11 files changed, 259 insertions(+), 22 deletions(-)
>>
>> diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
>> index 0eab454..1e345ed 100644
>> --- a/arch/ia64/mm/init.c
>> +++ b/arch/ia64/mm/init.c
>> @@ -688,6 +688,22 @@ int arch_add_memory(int nid, u64 start, u64 size)
>>
>> return ret;
>> }
>> +
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(u64 start, u64 size)
>> +{
>> + unsigned long start_pfn = start >> PAGE_SHIFT;
>> + unsigned long nr_pages = size >> PAGE_SHIFT;
>> + int ret;
>> +
>> + ret = __remove_pages(start_pfn, nr_pages);
>> + if (ret)
>> + pr_warn("%s: Problem encountered in __remove_pages() as"
>> + " ret=%d\n", __func__, ret);
>> +
>> + return ret;
>> +}
>> +#endif
>> #endif
>>
>
> in 3.5 ia64 implementation did not call __remove_pages at all. so why?
This function only reverts the things done in arch_add_memory(), and it will
be called when a memory device is removed.
When adding a memory device, __add_pages() is called in arch_add_memory(),
so call __remove_pages() in arch_remove_memory().
Thanks
Wen Congyang
>
>
>> /*
>> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
>> index baaafde..249cef4 100644
>> --- a/arch/powerpc/mm/mem.c
>> +++ b/arch/powerpc/mm/mem.c
>> @@ -133,6 +133,20 @@ int arch_add_memory(int nid, u64 start, u64 size)
>>
>> return __add_pages(nid, zone, start_pfn, nr_pages);
>> }
>> +
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(u64 start, u64 size)
>> +{
>> + unsigned long start_pfn = start >> PAGE_SHIFT;
>> + unsigned long nr_pages = size >> PAGE_SHIFT;
>> +
>> + start = (unsigned long)__va(start);
>> + if (remove_section_mapping(start, start + size))
>> + return -EINVAL;
>> +
>> + return __remove_pages(start_pfn, nr_pages);
>> +}
>> +#endif
>> #endif /* CONFIG_MEMORY_HOTPLUG */
>>
>> /*
>> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
>> index 6adbc08..ca4bc46 100644
>> --- a/arch/s390/mm/init.c
>> +++ b/arch/s390/mm/init.c
>> @@ -257,4 +257,12 @@ int arch_add_memory(int nid, u64 start, u64 size)
>> vmem_remove_mapping(start, size);
>> return rc;
>> }
>> +
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(u64 start, u64 size)
>> +{
>> + /* TODO */
>> + return -EBUSY;
>> +}
>> +#endif
>> #endif /* CONFIG_MEMORY_HOTPLUG */
>> diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
>> index 82cc576..fc84491 100644
>> --- a/arch/sh/mm/init.c
>> +++ b/arch/sh/mm/init.c
>> @@ -558,4 +558,19 @@ int memory_add_physaddr_to_nid(u64 addr)
>> EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
>> #endif
>>
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(u64 start, u64 size)
>> +{
>> + unsigned long start_pfn = start >> PAGE_SHIFT;
>> + unsigned long nr_pages = size >> PAGE_SHIFT;
>> + int ret;
>> +
>> + ret = __remove_pages(start_pfn, nr_pages);
>> + if (unlikely(ret))
>> + pr_warn("%s: Failed, __remove_pages() == %d\n", __func__,
>> + ret);
>> +
>> + return ret;
>> +}
>> +#endif
>> #endif /* CONFIG_MEMORY_HOTPLUG */
>> diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
>> index ef29d6c..2749515 100644
>> --- a/arch/tile/mm/init.c
>> +++ b/arch/tile/mm/init.c
>> @@ -935,6 +935,14 @@ int remove_memory(u64 start, u64 size)
>> {
>> return -EINVAL;
>> }
>> +
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(u64 start, u64 size)
>> +{
>> + /* TODO */
>> + return -EBUSY;
>> +}
>> +#endif
>> #endif
>>
>> struct kmem_cache *pgd_cache;
>> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
>> index 013286a..b725af2 100644
>> --- a/arch/x86/include/asm/pgtable_types.h
>> +++ b/arch/x86/include/asm/pgtable_types.h
>> @@ -334,6 +334,7 @@ static inline void update_page_count(int level, unsigned long pages) { }
>> * 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__ */
>>
>> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
>> index 575d86f..a690153 100644
>> --- a/arch/x86/mm/init_32.c
>> +++ b/arch/x86/mm/init_32.c
>> @@ -842,6 +842,16 @@ int arch_add_memory(int nid, u64 start, u64 size)
>>
>> return __add_pages(nid, zone, start_pfn, nr_pages);
>> }
>> +
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(unsigned long start, unsigned long size)
>> +{
>> + unsigned long start_pfn = start >> PAGE_SHIFT;
>> + unsigned long nr_pages = size >> PAGE_SHIFT;
>> +
>> + return __remove_pages(start_pfn, nr_pages);
>> +}
>> +#endif
>> #endif
>>
>> /*
>> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
>> index 2b6b4a3..f1554a9 100644
>> --- a/arch/x86/mm/init_64.c
>> +++ b/arch/x86/mm/init_64.c
>> @@ -675,6 +675,166 @@ int arch_add_memory(int nid, u64 start, u64 size)
>> }
>> 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(unsigned long start, unsigned long size)
>> +{
>> + unsigned long start_pfn = start >> PAGE_SHIFT;
>> + unsigned long nr_pages = size >> PAGE_SHIFT;
>> + int ret;
>> +
>> + ret = __remove_pages(start_pfn, nr_pages);
>> + WARN_ON_ONCE(ret);
>> +
>> + kernel_physical_mapping_remove(start, start + size);
>> +
>> + return ret;
>> +}
>> +#endif
>> #endif /* CONFIG_MEMORY_HOTPLUG */
>>
>> static struct kcore_list kcore_vsyscall;
>> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
>> index 931930a..c22963d 100644
>> --- a/arch/x86/mm/pageattr.c
>> +++ b/arch/x86/mm/pageattr.c
>> @@ -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, unsigned long address)
>> * 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, unsigned long address)
>> * 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;
>> }
>> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
>> index 8bf820d..0d500be 100644
>> --- a/include/linux/memory_hotplug.h
>> +++ b/include/linux/memory_hotplug.h
>> @@ -85,6 +85,7 @@ extern void __online_page_free(struct page *page);
>>
>> #ifdef CONFIG_MEMORY_HOTREMOVE
>> extern bool is_pageblock_removable_nolock(struct page *page);
>> +extern int arch_remove_memory(unsigned long start, unsigned long size);
>> #endif /* CONFIG_MEMORY_HOTREMOVE */
>>
>> /* reasonably generic interface to expand the physical pages in a zone */
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index a9e1579..0c932e1 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1071,6 +1071,7 @@ int __ref remove_memory(int nid, u64 start, u64 size)
>
> line 1071? which version does this patch base on? thanks a lot.
>
>
>> /* remove memmap entry */
>> firmware_map_remove(start, start + size, "System RAM");
>>
>> + arch_remove_memory(start, size);
>> out:
>> unlock_memory_hotplug();
>> return ret;
>> --
>> 1.7.1
>>
>> --
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>
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