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Commit ed2f2400 authored by Zhang Zhen's avatar Zhang Zhen Committed by Linus Torvalds
Browse files

memory-hotplug: add sysfs valid_zones attribute 



Currently memory-hotplug has two limits:

1. If the memory block is in ZONE_NORMAL, you can change it to
   ZONE_MOVABLE, but this memory block must be adjacent to ZONE_MOVABLE.

2. If the memory block is in ZONE_MOVABLE, you can change it to
   ZONE_NORMAL, but this memory block must be adjacent to ZONE_NORMAL.

With this patch, we can easy to know a memory block can be onlined to
which zone, and don't need to know the above two limits.

Updated the related Documentation.

[akpm@linux-foundation.org: use conventional comment layout]
[akpm@linux-foundation.org: fix build with CONFIG_MEMORY_HOTREMOVE=n]
[akpm@linux-foundation.org: remove unused local zone_prev]
Signed-off-by: default avatarZhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Wang Nan <wangnan0@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cc71aba3

Documentation/ABI/testing/sysfs-devices-memory

+8 −0
Original line number Diff line number Diff line
@@ -61,6 +61,14 @@ Users: hotplug memory remove tools 
		http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils





What:           /sys/devices/system/memory/memoryX/valid_zones

Date:           July 2014

Contact:	Zhang Zhen <zhenzhang.zhang@huawei.com>

Description:

		The file /sys/devices/system/memory/memoryX/valid_zones	is

		read-only and is designed to show which zone this memory

		block can be onlined to.



What:		/sys/devices/system/memoryX/nodeY

Date:		October 2009

Contact:	Linux Memory Management list <linux-mm@kvack.org>

Documentation/memory-hotplug.txt

+10 −1
Original line number Diff line number Diff line
@@ -155,6 +155,7 @@ Under each memory block, you can see 4 files: 
/sys/devices/system/memory/memoryXXX/phys_device

/sys/devices/system/memory/memoryXXX/state

/sys/devices/system/memory/memoryXXX/removable

/sys/devices/system/memory/memoryXXX/valid_zones



'phys_index'      : read-only and contains memory block id, same as XXX.

'state'           : read-write
@@ -170,6 +171,15 @@ Under each memory block, you can see 4 files: 
                    block is removable and a value of 0 indicates that

                    it is not removable. A memory block is removable only if

                    every section in the block is removable.

'valid_zones'     : read-only: designed to show which zones this memory block

		    can be onlined to.

		    The first column shows it's default zone.

		    "memory6/valid_zones: Normal Movable" shows this memoryblock

		    can be onlined to ZONE_NORMAL by default and to ZONE_MOVABLE

		    by online_movable.

		    "memory7/valid_zones: Movable Normal" shows this memoryblock

		    can be onlined to ZONE_MOVABLE by default and to ZONE_NORMAL

		    by online_kernel.



NOTE:

  These directories/files appear after physical memory hotplug phase.
@@ -408,7 +418,6 @@ node if necessary. 
  - allowing memory hot-add to ZONE_MOVABLE. maybe we need some switch like

    sysctl or new control file.

  - showing memory block and physical device relationship.

  - showing memory block is under ZONE_MOVABLE or not

  - test and make it better memory offlining.

  - support HugeTLB page migration and offlining.

  - memmap removing at memory offline.

drivers/base/memory.c

+42 −0
Original line number Diff line number Diff line
@@ -373,6 +373,45 @@ static ssize_t show_phys_device(struct device *dev, 
	return sprintf(buf, "%d\n", mem->phys_device);

}



#ifdef CONFIG_MEMORY_HOTREMOVE

static ssize_t show_valid_zones(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	struct memory_block *mem = to_memory_block(dev);

	unsigned long start_pfn, end_pfn;

	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;

	struct page *first_page;

	struct zone *zone;



	start_pfn = section_nr_to_pfn(mem->start_section_nr);

	end_pfn = start_pfn + nr_pages;

	first_page = pfn_to_page(start_pfn);



	/* The block contains more than one zone can not be offlined. */

	if (!test_pages_in_a_zone(start_pfn, end_pfn))

		return sprintf(buf, "none\n");



	zone = page_zone(first_page);



	if (zone_idx(zone) == ZONE_MOVABLE - 1) {

		/*The mem block is the last memoryblock of this zone.*/

		if (end_pfn == zone_end_pfn(zone))

			return sprintf(buf, "%s %s\n",

					zone->name, (zone + 1)->name);

	}



	if (zone_idx(zone) == ZONE_MOVABLE) {

		/*The mem block is the first memoryblock of ZONE_MOVABLE.*/

		if (start_pfn == zone->zone_start_pfn)

			return sprintf(buf, "%s %s\n",

					zone->name, (zone - 1)->name);

	}



	return sprintf(buf, "%s\n", zone->name);

}

static DEVICE_ATTR(valid_zones, 0444, show_valid_zones, NULL);

#endif



static DEVICE_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);

static DEVICE_ATTR(state, 0644, show_mem_state, store_mem_state);

static DEVICE_ATTR(phys_device, 0444, show_phys_device, NULL);
@@ -523,6 +562,9 @@ static struct attribute *memory_memblk_attrs[] = { 
	&dev_attr_state.attr,

	&dev_attr_phys_device.attr,

	&dev_attr_removable.attr,

#ifdef CONFIG_MEMORY_HOTREMOVE

	&dev_attr_valid_zones.attr,

#endif

	NULL

};

include/linux/memory_hotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ extern int zone_grow_waitqueues(struct zone *zone, unsigned long nr_pages); 
extern int add_one_highpage(struct page *page, int pfn, int bad_ppro);

/* VM interface that may be used by firmware interface */

extern int online_pages(unsigned long, unsigned long, int);

extern int test_pages_in_a_zone(unsigned long, unsigned long);

extern void __offline_isolated_pages(unsigned long, unsigned long);



typedef void (*online_page_callback_t)(struct page *page);

mm/memory_hotplug.c

+1 −1
Original line number Diff line number Diff line
@@ -1307,7 +1307,7 @@ int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) 
/*

 * Confirm all pages in a range [start, end) is belongs to the same zone.

 */

static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)

int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)

{

	unsigned long pfn;

	struct zone *zone = NULL;