Subject: Re: [PATCH v3 11/12] memory-hotplug: remove sysfs file of node

From: Yasuaki Ishimatsu <[email-masked]>
Date: Mon, 19 Nov 2012 19:08:55 +0900

Hi Wen,

This patch cannot be applied, if I apply latest acpi framework's patch-set:

https://lkml.org/lkml/2012/11/15/21

Because acpi_memory_disable_device() is gone by the patch-set.

I updated the patch and attached it on the mail.

2012/11/01 18:44, Wen Congyang wrote:
> This patch introduces a new function try_offline_node() to
> remove sysfs file of node when all memory sections of this
> node are removed. If some memory sections of this node are
> not removed, this function does nothing.
> 
> CC: David Rientjes <[email-masked]>
> CC: Jiang Liu <[email-masked]>
> CC: Len Brown <[email-masked]>
> CC: Christoph Lameter <[email-masked]>
> Cc: Minchan Kim <[email-masked]>
> CC: Andrew Morton <[email-masked]>
> CC: KOSAKI Motohiro <[email-masked]>
> CC: Yasuaki Ishimatsu <[email-masked]>
> Signed-off-by: Wen Congyang <[email-masked]>
> ---
>   drivers/acpi/acpi_memhotplug.c |  8 +++++-
>   include/linux/memory_hotplug.h |  2 +-
>   mm/memory_hotplug.c            | 58 ++++++++++++++++++++++++++++++++++++++++--
>   3 files changed, 64 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 24c807f..0780f99 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -310,7 +310,9 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>   {
>   	int result;
>   	struct acpi_memory_info *info, *n;
> +	int node;
>   
> +	node = acpi_get_node(mem_device->device->handle);
>   
>   	/*
>   	 * Ask the VM to offline this memory range.
> @@ -318,7 +320,11 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
>   	 */
>   	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
>   		if (info->enabled) {
> -			result = remove_memory(info->start_addr, info->length);
> +			if (node < 0)
> +				node = memory_add_physaddr_to_nid(
> +					info->start_addr);
> +			result = remove_memory(node, info->start_addr,
> +				info->length);
>   			if (result)
>   				return result;
>   		}
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index d4c4402..7b4cfe6 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -231,7 +231,7 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
>   extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
>   extern int offline_memory_block(struct memory_block *mem);
>   extern bool is_memblock_offlined(struct memory_block *mem);
> -extern int remove_memory(u64 start, u64 size);
> +extern int remove_memory(int node, u64 start, u64 size);
>   extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
>   								int nr_pages);
>   extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 7bcced0..d965da3 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -29,6 +29,7 @@
>   #include <linux/suspend.h>
>   #include <linux/mm_inline.h>
>   #include <linux/firmware-map.h>
> +#include <linux/stop_machine.h>
>   
>   #include <asm/tlbflush.h>
>   
> @@ -1299,7 +1300,58 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
>   	return ret;
>   }
>   
> -int __ref remove_memory(u64 start, u64 size)
> +static int check_cpu_on_node(void *data)
> +{
> +	struct pglist_data *pgdat = data;
> +	int cpu;
> +
> +	for_each_present_cpu(cpu) {
> +		if (cpu_to_node(cpu) == pgdat->node_id)
> +			/*
> +			 * the cpu on this node isn't removed, and we can't
> +			 * offline this node.
> +			 */
> +			return -EBUSY;
> +	}
> +
> +	return 0;
> +}
> +
> +/* offline the node if all memory sections of this node are removed */
> +static void try_offline_node(int nid)
> +{
> +	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
> +	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
> +	unsigned long pfn;
> +
> +	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> +		unsigned long section_nr = pfn_to_section_nr(pfn);
> +
> +		if (!present_section_nr(section_nr))
> +			continue;
> +
> +		if (pfn_to_nid(pfn) != nid)
> +			continue;
> +
> +		/*
> +		 * some memory sections of this node are not removed, and we
> +		 * can't offline node now.
> +		 */
> +		return;
> +	}
> +
> +	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
> +		return;
> +
> +	/*
> +	 * all memory/cpu of this node are removed, we can offline this
> +	 * node now.
> +	 */
> +	node_set_offline(nid);
> +	unregister_one_node(nid);
> +}
> +
> +int __ref remove_memory(int nid, u64 start, u64 size)
>   {
>   	unsigned long start_pfn, end_pfn;
>   	int ret = 0;
> @@ -1346,6 +1398,8 @@ repeat:
>   
>   	arch_remove_memory(start, size);
>   
> +	try_offline_node(nid);
> +
>   	unlock_memory_hotplug();
>   
>   	return 0;
> @@ -1355,7 +1409,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
>   {
>   	return -EINVAL;
>   }
> -int remove_memory(u64 start, u64 size)
> +int remove_memory(int nid, u64 start, u64 size)
>   {
>   	return -EINVAL;
>   }
> 

---
This patch introduces a new function try_offline_node() to
remove sysfs file of node when all memory sections of this
node are removed. If some memory sections of this node are
not removed, this function does nothing.

CC: David Rientjes <[email-masked]>
CC: Jiang Liu <[email-masked]>
CC: Len Brown <[email-masked]>
CC: Christoph Lameter <[email-masked]>
Cc: Minchan Kim <[email-masked]>
CC: Andrew Morton <[email-masked]>
CC: KOSAKI Motohiro <[email-masked]>
CC: Yasuaki Ishimatsu <[email-masked]>
Signed-off-by: Wen Congyang <[email-masked]>
---
 drivers/acpi/acpi_memhotplug.c |    9 +++++-
 include/linux/memory_hotplug.h |    2 -
 mm/memory_hotplug.c            |   58 +++++++++++++++++++++++++++++++++++++++--
 3 files changed, 65 insertions(+), 4 deletions(-)

Index: linux-3.7-rc6/drivers/acpi/acpi_memhotplug.c
===================================================================
--- linux-3.7-rc6.orig/drivers/acpi/acpi_memhotplug.c	2012-11-19 16:16:55.161912688 +0900
+++ linux-3.7-rc6/drivers/acpi/acpi_memhotplug.c	2012-11-19 16:17:05.346912109 +0900
@@ -295,6 +295,9 @@ static int acpi_memory_remove_memory(str
 {
 	int result = 0;
 	struct acpi_memory_info *info, *n;
+	int node;
+
+	node = acpi_get_node(mem_device->device->handle);
 
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (info->failed)
@@ -308,7 +311,11 @@ static int acpi_memory_remove_memory(str
 			 */
 			return -EBUSY;
 
-		result = remove_memory(info->start_addr, info->length);
+		if (node < 0)
+			node = memory_add_physaddr_to_nid(
+				info->start_addr);
+		result = remove_memory(node, info->start_addr,
+			info->length);
 		if (result)
 			return result;
 
Index: linux-3.7-rc6/include/linux/memory_hotplug.h
===================================================================
--- linux-3.7-rc6.orig/include/linux/memory_hotplug.h	2012-11-19 16:16:55.167912687 +0900
+++ linux-3.7-rc6/include/linux/memory_hotplug.h	2012-11-19 16:17:05.348912109 +0900
@@ -242,7 +242,7 @@ extern int arch_add_memory(int nid, u64 
 extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
 extern int offline_memory_block(struct memory_block *mem);
 extern bool is_memblock_offlined(struct memory_block *mem);
-extern int remove_memory(u64 start, u64 size);
+extern int remove_memory(int node, u64 start, u64 size);
 extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
 								int nr_pages);
 extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
Index: linux-3.7-rc6/mm/memory_hotplug.c
===================================================================
--- linux-3.7-rc6.orig/mm/memory_hotplug.c	2012-11-19 16:16:55.164912687 +0900
+++ linux-3.7-rc6/mm/memory_hotplug.c	2012-11-19 16:17:05.356912108 +0900
@@ -29,6 +29,7 @@
 #include <linux/suspend.h>
 #include <linux/mm_inline.h>
 #include <linux/firmware-map.h>
+#include <linux/stop_machine.h>
 
 #include <asm/tlbflush.h>
 
@@ -1652,7 +1653,58 @@ static int is_memblock_offlined_cb(struc
 	return ret;
 }
 
-int __ref remove_memory(u64 start, u64 size)
+static int check_cpu_on_node(void *data)
+{
+	struct pglist_data *pgdat = data;
+	int cpu;
+
+	for_each_present_cpu(cpu) {
+		if (cpu_to_node(cpu) == pgdat->node_id)
+			/*
+			 * the cpu on this node isn't removed, and we can't
+			 * offline this node.
+			 */
+			return -EBUSY;
+	}
+
+	return 0;
+}
+
+/* offline the node if all memory sections of this node are removed */
+static void try_offline_node(int nid)
+{
+	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
+	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
+	unsigned long pfn;
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+		unsigned long section_nr = pfn_to_section_nr(pfn);
+
+		if (!present_section_nr(section_nr))
+			continue;
+
+		if (pfn_to_nid(pfn) != nid)
+			continue;
+
+		/*
+		 * some memory sections of this node are not removed, and we
+		 * can't offline node now.
+		 */
+		return;
+	}
+
+	if (stop_machine(check_cpu_on_node, NODE_DATA(nid), NULL))
+		return;
+
+	/*
+	 * all memory/cpu of this node are removed, we can offline this
+	 * node now.
+	 */
+	node_set_offline(nid);
+	unregister_one_node(nid);
+}
+
+int __ref remove_memory(int nid, u64 start, u64 size)
 {
 	unsigned long start_pfn, end_pfn;
 	int ret = 0;
@@ -1699,6 +1751,8 @@ repeat:
 
 	arch_remove_memory(start, size);
 
+	try_offline_node(nid);
+
 	unlock_memory_hotplug();
 
 	return 0;
@@ -1708,7 +1762,7 @@ int offline_pages(unsigned long start_pf
 {
 	return -EINVAL;
 }
-int remove_memory(u64 start, u64 size)
+int remove_memory(int nid, u64 start, u64 size)
 {
 	return -EINVAL;
 }