Patchwork [RFC,6/8] memory-hotplug: introduce new function arch_remove_memory()

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Submitter Wen Congyang
Date July 20, 2012, 7:12 a.m.
Message ID <500904D6.3030109@cn.fujitsu.com>
Download mbox | patch
Permalink /patch/172143/
State Not Applicable
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Comments

Wen Congyang - July 20, 2012, 7:12 a.m.
We don't call __add_pages() directly in the function add_memory()
because some other architecture related thins needs to be done
before or after calling __add_pages(). So we should not call
__remove_pages() directly in the function remove_memory.
Introduce new function arch_remove_memory() to revert the things done
in arch_add_memory().

Note: the function for x86_64 will be implemented later. And 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/mm/init_32.c          |   10 ++++++++++
 arch/x86/mm/init_64.c          |    7 +++++++
 include/linux/memory_hotplug.h |    1 +
 mm/memory_hotplug.c            |    2 +-
 9 files changed, 80 insertions(+), 1 deletions(-)
Yasuaki Ishimatsu - July 20, 2012, 8:21 a.m.
2012/07/20 16:12, Wen Congyang wrote:
> We don't call __add_pages() directly in the function add_memory()
> because some other architecture related thins needs to be done
> before or after calling __add_pages(). So we should not call
> __remove_pages() directly in the function remove_memory.
> Introduce new function arch_remove_memory() to revert the things done
> in arch_add_memory().
>
> Note: the function for x86_64 will be implemented later. And I don't
> know how to implement it for s390.

I think you need cc to other arch ML for reviewing the patch.


> 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/mm/init_32.c          |   10 ++++++++++
>   arch/x86/mm/init_64.c          |    7 +++++++
>   include/linux/memory_hotplug.h |    1 +
>   mm/memory_hotplug.c            |    2 +-
>   9 files changed, 80 insertions(+), 1 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
>
>   /*
> 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 2bea060..3de0d5b 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -259,4 +259,12 @@ 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 630dd2c..bdd8a99 100644
> --- a/arch/tile/mm/init.c
> +++ b/arch/tile/mm/init.c
> @@ -947,6 +947,14 @@ 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/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 9e635b3..78b94bc 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -675,6 +675,13 @@ int arch_add_memory(int nid, u64 start, u64 size)
>   }
>   EXPORT_SYMBOL_GPL(arch_add_memory);
>
> +#ifdef CONFIG_MEMORY_HOTREMOVE
> +int arch_remove_memory(unsigned long start, unsigned long size)
> +{
> +	/* TODO */
> +	return -EBUSY;
> +}
> +#endif

Why does not the function call __remove_pages()?

Thanks,
Yasuaki ishimatsu

>   #endif /* CONFIG_MEMORY_HOTPLUG */
>
>   static struct kcore_list kcore_vsyscall;
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 2ba0a1a..8639799 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -84,6 +84,7 @@ 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 dccdf71..cc2c8b9 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1055,7 +1055,7 @@ int __ref remove_memory(int nid, u64 start, u64 size)
>   		unregister_one_node(nid);
>   	}
>
> -	__remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
> +	arch_remove_memory(start, size);
>   out:
>   	unlock_memory_hotplug();
>   	return ret;
>
Wen Congyang - July 20, 2012, 8:38 a.m.
At 07/20/2012 04:21 PM, Yasuaki Ishimatsu Wrote:
> 2012/07/20 16:12, Wen Congyang wrote:
>> We don't call __add_pages() directly in the function add_memory()
>> because some other architecture related thins needs to be done
>> before or after calling __add_pages(). So we should not call
>> __remove_pages() directly in the function remove_memory.
>> Introduce new function arch_remove_memory() to revert the things done
>> in arch_add_memory().
>>
>> Note: the function for x86_64 will be implemented later. And I don't
>> know how to implement it for s390.
> 
> I think you need cc to other arch ML for reviewing the patch.

I forgot to do it.

> 
> 
>> 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/mm/init_32.c          |   10 ++++++++++
>>   arch/x86/mm/init_64.c          |    7 +++++++
>>   include/linux/memory_hotplug.h |    1 +
>>   mm/memory_hotplug.c            |    2 +-
>>   9 files changed, 80 insertions(+), 1 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
>>
>>   /*
>> 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 2bea060..3de0d5b 100644
>> --- a/arch/s390/mm/init.c
>> +++ b/arch/s390/mm/init.c
>> @@ -259,4 +259,12 @@ 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 630dd2c..bdd8a99 100644
>> --- a/arch/tile/mm/init.c
>> +++ b/arch/tile/mm/init.c
>> @@ -947,6 +947,14 @@ 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/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 9e635b3..78b94bc 100644
>> --- a/arch/x86/mm/init_64.c
>> +++ b/arch/x86/mm/init_64.c
>> @@ -675,6 +675,13 @@ int arch_add_memory(int nid, u64 start, u64 size)
>>   }
>>   EXPORT_SYMBOL_GPL(arch_add_memory);
>>
>> +#ifdef CONFIG_MEMORY_HOTREMOVE
>> +int arch_remove_memory(unsigned long start, unsigned long size)
>> +{
>> +    /* TODO */
>> +    return -EBUSY;
>> +}
>> +#endif
> 
> Why does not the function call __remove_pages()?

arch_remove_memory() should clear the page table after remove pages here.
I implement this function in patch 8.

Thanks
Wen Congyang

> 
> Thanks,
> Yasuaki ishimatsu
> 
>>   #endif /* CONFIG_MEMORY_HOTPLUG */
>>
>>   static struct kcore_list kcore_vsyscall;
>> diff --git a/include/linux/memory_hotplug.h
>> b/include/linux/memory_hotplug.h
>> index 2ba0a1a..8639799 100644
>> --- a/include/linux/memory_hotplug.h
>> +++ b/include/linux/memory_hotplug.h
>> @@ -84,6 +84,7 @@ 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 dccdf71..cc2c8b9 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -1055,7 +1055,7 @@ int __ref remove_memory(int nid, u64 start, u64
>> size)
>>           unregister_one_node(nid);
>>       }
>>
>> -    __remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
>> +    arch_remove_memory(start, size);
>>   out:
>>       unlock_memory_hotplug();
>>       return ret;
>>
> 
> 
>

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 2bea060..3de0d5b 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -259,4 +259,12 @@  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 630dd2c..bdd8a99 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -947,6 +947,14 @@  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/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 9e635b3..78b94bc 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -675,6 +675,13 @@  int arch_add_memory(int nid, u64 start, u64 size)
 }
 EXPORT_SYMBOL_GPL(arch_add_memory);
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(unsigned long start, unsigned long size)
+{
+	/* TODO */
+	return -EBUSY;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static struct kcore_list kcore_vsyscall;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 2ba0a1a..8639799 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -84,6 +84,7 @@  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 dccdf71..cc2c8b9 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1055,7 +1055,7 @@  int __ref remove_memory(int nid, u64 start, u64 size)
 		unregister_one_node(nid);
 	}
 
-	__remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT);
+	arch_remove_memory(start, size);
 out:
 	unlock_memory_hotplug();
 	return ret;