Patchwork [v4,3/13] memory-hotplug : check whether memory is present or not

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Submitter Yasuaki Ishimatsu
Date July 18, 2012, 10:07 a.m.
Message ID <50068AE9.3050804@jp.fujitsu.com>
Download mbox | patch
Permalink /patch/171625/
State Not Applicable
Headers show

Comments

Yasuaki Ishimatsu - July 18, 2012, 10:07 a.m.
If system supports memory hot-remove, online_pages() may online removed pages.
So online_pages() need to check whether onlining pages are present or not.

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: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

---
 include/linux/mmzone.h |   21 +++++++++++++++++++++
 mm/memory_hotplug.c    |   13 +++++++++++++
 2 files changed, 34 insertions(+)
Wen Congyang - July 18, 2012, 10:25 a.m.
At 07/18/2012 06:07 PM, Yasuaki Ishimatsu Wrote:
> If system supports memory hot-remove, online_pages() may online removed pages.
> So online_pages() need to check whether onlining pages are present or not.
> 
> 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: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> 
> ---
>  include/linux/mmzone.h |   21 +++++++++++++++++++++
>  mm/memory_hotplug.c    |   13 +++++++++++++
>  2 files changed, 34 insertions(+)
> 
> Index: linux-3.5-rc6/include/linux/mmzone.h
> ===================================================================
> --- linux-3.5-rc6.orig/include/linux/mmzone.h	2012-07-08 09:23:56.000000000 +0900
> +++ linux-3.5-rc6/include/linux/mmzone.h	2012-07-17 16:10:21.588186145 +0900
> @@ -1168,6 +1168,27 @@ void sparse_init(void);
>  #define sparse_index_init(_sec, _nid)  do {} while (0)
>  #endif /* CONFIG_SPARSEMEM */
>  
> +#ifdef CONFIG_SPARSEMEM
> +static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
> +{
> +	int i;
> +	for (i = 0; i < nr_pages; i++) {
> +		if (pfn_present(pfn + 1))
> +			continue;
> +		else {
> +			unlock_memory_hotplug();

Why do you unlock memory hotplug here? The caller will do it.

Thanks
Wen Congyang

> +			return -EINVAL;
> +		}
> +	}
> +	return 0;
> +}
> +#else
> +static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
> +{
> +	return 0;
> +}
> +#endif /* CONFIG_SPARSEMEM*/
> +
>  #ifdef CONFIG_NODES_SPAN_OTHER_NODES
>  bool early_pfn_in_nid(unsigned long pfn, int nid);
>  #else
> Index: linux-3.5-rc6/mm/memory_hotplug.c
> ===================================================================
> --- linux-3.5-rc6.orig/mm/memory_hotplug.c	2012-07-17 14:26:40.000000000 +0900
> +++ linux-3.5-rc6/mm/memory_hotplug.c	2012-07-17 16:09:50.070580170 +0900
> @@ -467,6 +467,19 @@ int __ref online_pages(unsigned long pfn
>  	struct memory_notify arg;
>  
>  	lock_memory_hotplug();
> +	/*
> + 	 * If system supports memory hot-remove, the memory may have been
> + 	 * removed. So we check whether the memory has been removed or not.
> + 	 *
> + 	 * Note: When CONFIG_SPARSEMEM is defined, pfns_present() become
> + 	 *       effective. If CONFIG_SPARSEMEM is not defined, pfns_present()
> + 	 *       always returns 0.
> + 	 */
> +	ret = pfns_present(pfn, nr_pages);
> +	if (ret) {
> +		unlock_memory_hotplug();
> +		return ret;
> +	}
>  	arg.start_pfn = pfn;
>  	arg.nr_pages = nr_pages;
>  	arg.status_change_nid = -1;
> 
>
Yasuaki Ishimatsu - July 18, 2012, 10:25 a.m.
Hi Wen,

2012/07/18 19:25, Wen Congyang wrote:
> At 07/18/2012 06:07 PM, Yasuaki Ishimatsu Wrote:
>> If system supports memory hot-remove, online_pages() may online removed pages.
>> So online_pages() need to check whether onlining pages are present or not.
>>
>> 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: Wen Congyang <wency@cn.fujitsu.com>
>> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
>>
>> ---
>>   include/linux/mmzone.h |   21 +++++++++++++++++++++
>>   mm/memory_hotplug.c    |   13 +++++++++++++
>>   2 files changed, 34 insertions(+)
>>
>> Index: linux-3.5-rc6/include/linux/mmzone.h
>> ===================================================================
>> --- linux-3.5-rc6.orig/include/linux/mmzone.h	2012-07-08 09:23:56.000000000 +0900
>> +++ linux-3.5-rc6/include/linux/mmzone.h	2012-07-17 16:10:21.588186145 +0900
>> @@ -1168,6 +1168,27 @@ void sparse_init(void);
>>   #define sparse_index_init(_sec, _nid)  do {} while (0)
>>   #endif /* CONFIG_SPARSEMEM */
>>   
>> +#ifdef CONFIG_SPARSEMEM
>> +static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
>> +{
>> +	int i;
>> +	for (i = 0; i < nr_pages; i++) {
>> +		if (pfn_present(pfn + 1))
>> +			continue;
>> +		else {
>> +			unlock_memory_hotplug();
> 
> Why do you unlock memory hotplug here? The caller will do it.

Ah, you are right. In this case, the function should only return -EINVAL.

Thansks,
Yasuaki Ishimatsu
> 
> Thanks
> Wen Congyang
> 
>> +			return -EINVAL;
>> +		}
>> +	}
>> +	return 0;
>> +}
>> +#else
>> +static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
>> +{
>> +	return 0;
>> +}
>> +#endif /* CONFIG_SPARSEMEM*/
>> +
>>   #ifdef CONFIG_NODES_SPAN_OTHER_NODES
>>   bool early_pfn_in_nid(unsigned long pfn, int nid);
>>   #else
>> Index: linux-3.5-rc6/mm/memory_hotplug.c
>> ===================================================================
>> --- linux-3.5-rc6.orig/mm/memory_hotplug.c	2012-07-17 14:26:40.000000000 +0900
>> +++ linux-3.5-rc6/mm/memory_hotplug.c	2012-07-17 16:09:50.070580170 +0900
>> @@ -467,6 +467,19 @@ int __ref online_pages(unsigned long pfn
>>   	struct memory_notify arg;
>>   
>>   	lock_memory_hotplug();
>> +	/*
>> + 	 * If system supports memory hot-remove, the memory may have been
>> + 	 * removed. So we check whether the memory has been removed or not.
>> + 	 *
>> + 	 * Note: When CONFIG_SPARSEMEM is defined, pfns_present() become
>> + 	 *       effective. If CONFIG_SPARSEMEM is not defined, pfns_present()
>> + 	 *       always returns 0.
>> + 	 */
>> +	ret = pfns_present(pfn, nr_pages);
>> +	if (ret) {
>> +		unlock_memory_hotplug();
>> +		return ret;
>> +	}
>>   	arg.start_pfn = pfn;
>>   	arg.nr_pages = nr_pages;
>>   	arg.status_change_nid = -1;
>>
>>
>
Wen Congyang - July 18, 2012, 10:56 a.m.
At 07/18/2012 06:07 PM, Yasuaki Ishimatsu Wrote:
> If system supports memory hot-remove, online_pages() may online removed pages.
> So online_pages() need to check whether onlining pages are present or not.
> 
> 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: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> 
> ---
>  include/linux/mmzone.h |   21 +++++++++++++++++++++
>  mm/memory_hotplug.c    |   13 +++++++++++++
>  2 files changed, 34 insertions(+)
> 
> Index: linux-3.5-rc6/include/linux/mmzone.h
> ===================================================================
> --- linux-3.5-rc6.orig/include/linux/mmzone.h	2012-07-08 09:23:56.000000000 +0900
> +++ linux-3.5-rc6/include/linux/mmzone.h	2012-07-17 16:10:21.588186145 +0900
> @@ -1168,6 +1168,27 @@ void sparse_init(void);
>  #define sparse_index_init(_sec, _nid)  do {} while (0)
>  #endif /* CONFIG_SPARSEMEM */
>  
> +#ifdef CONFIG_SPARSEMEM
> +static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
> +{
> +	int i;
> +	for (i = 0; i < nr_pages; i++) {
> +		if (pfn_present(pfn + 1))
> +			continue;
> +		else {
> +			unlock_memory_hotplug();
> +			return -EINVAL;
> +		}
> +	}
> +	return 0;
> +}
> +#else
> +static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
> +{
> +	return 0;
> +}
> +#endif /* CONFIG_SPARSEMEM*/
> +
>  #ifdef CONFIG_NODES_SPAN_OTHER_NODES
>  bool early_pfn_in_nid(unsigned long pfn, int nid);
>  #else
> Index: linux-3.5-rc6/mm/memory_hotplug.c
> ===================================================================
> --- linux-3.5-rc6.orig/mm/memory_hotplug.c	2012-07-17 14:26:40.000000000 +0900
> +++ linux-3.5-rc6/mm/memory_hotplug.c	2012-07-17 16:09:50.070580170 +0900
> @@ -467,6 +467,19 @@ int __ref online_pages(unsigned long pfn
>  	struct memory_notify arg;
>  
>  	lock_memory_hotplug();
> +	/*
> + 	 * If system supports memory hot-remove, the memory may have been
> + 	 * removed. So we check whether the memory has been removed or not.
> + 	 *
> + 	 * Note: When CONFIG_SPARSEMEM is defined, pfns_present() become
> + 	 *       effective. If CONFIG_SPARSEMEM is not defined, pfns_present()
> + 	 *       always returns 0.
> + 	 */

There is one space before tab in the comment.

Thanks
Wen Congyang

> +	ret = pfns_present(pfn, nr_pages);
> +	if (ret) {
> +		unlock_memory_hotplug();
> +		return ret;
> +	}
>  	arg.start_pfn = pfn;
>  	arg.nr_pages = nr_pages;
>  	arg.status_change_nid = -1;
> 
>

Patch

Index: linux-3.5-rc6/include/linux/mmzone.h
===================================================================
--- linux-3.5-rc6.orig/include/linux/mmzone.h	2012-07-08 09:23:56.000000000 +0900
+++ linux-3.5-rc6/include/linux/mmzone.h	2012-07-17 16:10:21.588186145 +0900
@@ -1168,6 +1168,27 @@  void sparse_init(void);
 #define sparse_index_init(_sec, _nid)  do {} while (0)
 #endif /* CONFIG_SPARSEMEM */
 
+#ifdef CONFIG_SPARSEMEM
+static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
+{
+	int i;
+	for (i = 0; i < nr_pages; i++) {
+		if (pfn_present(pfn + 1))
+			continue;
+		else {
+			unlock_memory_hotplug();
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+#else
+static inline int pfns_present(unsigned long pfn, unsigned long nr_pages)
+{
+	return 0;
+}
+#endif /* CONFIG_SPARSEMEM*/
+
 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
 bool early_pfn_in_nid(unsigned long pfn, int nid);
 #else
Index: linux-3.5-rc6/mm/memory_hotplug.c
===================================================================
--- linux-3.5-rc6.orig/mm/memory_hotplug.c	2012-07-17 14:26:40.000000000 +0900
+++ linux-3.5-rc6/mm/memory_hotplug.c	2012-07-17 16:09:50.070580170 +0900
@@ -467,6 +467,19 @@  int __ref online_pages(unsigned long pfn
 	struct memory_notify arg;
 
 	lock_memory_hotplug();
+	/*
+ 	 * If system supports memory hot-remove, the memory may have been
+ 	 * removed. So we check whether the memory has been removed or not.
+ 	 *
+ 	 * Note: When CONFIG_SPARSEMEM is defined, pfns_present() become
+ 	 *       effective. If CONFIG_SPARSEMEM is not defined, pfns_present()
+ 	 *       always returns 0.
+ 	 */
+	ret = pfns_present(pfn, nr_pages);
+	if (ret) {
+		unlock_memory_hotplug();
+		return ret;
+	}
 	arg.start_pfn = pfn;
 	arg.nr_pages = nr_pages;
 	arg.status_change_nid = -1;