diff mbox

[RFC,v5,12/19] memory-hotplug: introduce new function arch_remove_memory()

Message ID 50126E2F.8010301@cn.fujitsu.com (mailing list archive)
State New, archived
Headers show

Commit Message

Wen Congyang July 27, 2012, 10:32 a.m. UTC
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@google.com>
CC: Jiang Liu <liuj97@gmail.com>
CC: Len Brown <len.brown@intel.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.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(-)

Comments

Heiko Carstens July 30, 2012, 10:23 a.m. UTC | #1
On Fri, Jul 27, 2012 at 06:32:15PM +0800, Wen Congyang wrote:
> 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).

There is no hardware or firmware interface which could trigger a
hot memory remove on s390. So there is nothing that needs to be
implemented.

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Wen Congyang July 30, 2012, 10:35 a.m. UTC | #2
At 07/30/2012 06:23 PM, Heiko Carstens Wrote:
> On Fri, Jul 27, 2012 at 06:32:15PM +0800, Wen Congyang wrote:
>> 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).
> 
> There is no hardware or firmware interface which could trigger a
> hot memory remove on s390. So there is nothing that needs to be
> implemented.

Thanks for providing this information.

According to this, arch_remove_memory() for s390 can just return -EBUSY.

Thanks
Wen Congyang

> 
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Gerald Schaefer July 31, 2012, 12:40 p.m. UTC | #3
On Mon, 30 Jul 2012 18:35:37 +0800
Wen Congyang <wency@cn.fujitsu.com> wrote:

> At 07/30/2012 06:23 PM, Heiko Carstens Wrote:
> > On Fri, Jul 27, 2012 at 06:32:15PM +0800, Wen Congyang wrote:
> >> 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).
> > 
> > There is no hardware or firmware interface which could trigger a
> > hot memory remove on s390. So there is nothing that needs to be
> > implemented.
> 
> Thanks for providing this information.
> 
> According to this, arch_remove_memory() for s390 can just return
> -EBUSY.

Yes, but there is a prototype mismatch for arch_remove_memory() on s390
and also other architectures (u64 vs. unsigned long).

arch/s390/mm/init.c:262: error: conflicting types for
‘arch_remove_memory’ include/linux/memory_hotplug.h:88: error: previous
declaration of ‘arch_remove_memory’ was here

In memory_hotplug.h you have:
extern int arch_remove_memory(unsigned long start, unsigned long size);

On all archs other than x86 you have:
int arch_remove_memory(u64 start, u64 size)

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Wen Congyang Aug. 1, 2012, 1:42 a.m. UTC | #4
At 07/31/2012 08:40 PM, Gerald Schaefer Wrote:
> On Mon, 30 Jul 2012 18:35:37 +0800
> Wen Congyang <wency@cn.fujitsu.com> wrote:
> 
>> At 07/30/2012 06:23 PM, Heiko Carstens Wrote:
>>> On Fri, Jul 27, 2012 at 06:32:15PM +0800, Wen Congyang wrote:
>>>> 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).
>>>
>>> There is no hardware or firmware interface which could trigger a
>>> hot memory remove on s390. So there is nothing that needs to be
>>> implemented.
>>
>> Thanks for providing this information.
>>
>> According to this, arch_remove_memory() for s390 can just return
>> -EBUSY.
> 
> Yes, but there is a prototype mismatch for arch_remove_memory() on s390
> and also other architectures (u64 vs. unsigned long).
> 
> arch/s390/mm/init.c:262: error: conflicting types for
> ‘arch_remove_memory’ include/linux/memory_hotplug.h:88: error: previous
> declaration of ‘arch_remove_memory’ was here
> 
> In memory_hotplug.h you have:
> extern int arch_remove_memory(unsigned long start, unsigned long size);
> 
> On all archs other than x86 you have:
> int arch_remove_memory(u64 start, u64 size)

Thanks for pointing it out. I will fix it.

Wen Congyang

> 
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> 

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jencce zhou Aug. 1, 2012, 2:44 a.m. UTC | #5
2012/7/27 Wen Congyang <wency@cn.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@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Christoph Lameter <cl@linux.com>
> Cc: Minchan Kim <minchan.kim@gmail.com>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.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?


>  /*
> 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
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> Please read the FAQ at  http://www.tux.org/lkml/
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Wen Congyang Aug. 1, 2012, 6:06 a.m. UTC | #6
At 08/01/2012 10:44 AM, jencce zhou Wrote:
> 2012/7/27 Wen Congyang <wency@cn.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@google.com>
>> CC: Jiang Liu <liuj97@gmail.com>
>> CC: Len Brown <len.brown@intel.com>
>> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> CC: Paul Mackerras <paulus@samba.org>
>> CC: Christoph Lameter <cl@linux.com>
>> Cc: Minchan Kim <minchan.kim@gmail.com>
>> CC: Andrew Morton <akpm@linux-foundation.org>
>> CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
>> CC: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.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
>>
>> --
>> 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/
> 

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diff mbox

Patch

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
 
 /*
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)
 	/* remove memmap entry */
 	firmware_map_remove(start, start + size, "System RAM");
 
+	arch_remove_memory(start, size);
 out:
 	unlock_memory_hotplug();
 	return ret;