[PATCH v2] memory-hotplug: add sysfs zones_online_to attribute
From: Zhang Zhen
Date: Wed Aug 13 2014 - 00:10:56 EST
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.
Change v1 -> v2:
- optimize the implementation following Dave Hansen's suggestion
Signed-off-by: Zhang Zhen <zhenzhang.zhang@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-devices-memory | 8 ++++
Documentation/memory-hotplug.txt | 4 +-
drivers/base/memory.c | 62 ++++++++++++++++++++++++++
include/linux/memory_hotplug.h | 1 +
mm/memory_hotplug.c | 2 +-
5 files changed, 75 insertions(+), 2 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory
index 7405de2..2b2a1d7 100644
--- a/Documentation/ABI/testing/sysfs-devices-memory
+++ b/Documentation/ABI/testing/sysfs-devices-memory
@@ -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/zones_online_to
+Date: July 2014
+Contact: Zhang Zhen <zhenzhang.zhang@xxxxxxxxxx>
+Description:
+ The file /sys/devices/system/memory/memoryX/zones_online_to
+ 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@xxxxxxxxx>
diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt
index 45134dc..5b34e33 100644
--- a/Documentation/memory-hotplug.txt
+++ b/Documentation/memory-hotplug.txt
@@ -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/zones_online_to
'phys_index' : read-only and contains memory block id, same as XXX.
'state' : read-write
@@ -170,6 +171,8 @@ 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.
+'zones_online_to' : read-only: designed to show which zone this memory block
+ can be onlined to.
NOTE:
These directories/files appear after physical memory hotplug phase.
@@ -408,7 +411,6 @@ 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.
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index a2e13e2..b5d693f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -373,10 +373,71 @@ static ssize_t show_phys_device(struct device *dev,
return sprintf(buf, "%d\n", mem->phys_device);
}
+static int __zones_online_to(unsigned long end_pfn,
+ struct page *first_page, unsigned long nr_pages)
+{
+ struct zone *zone_next;
+
+ /*The mem block is the last block of memory.*/
+ if (!pfn_valid(end_pfn + 1))
+ return 1;
+ zone_next = page_zone(first_page + nr_pages);
+ if (zone_idx(zone_next) == ZONE_MOVABLE)
+ return 1;
+ return 0;
+}
+
+static ssize_t show_zones_online_to(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, *zone_prev;
+
+ 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);
+
+#ifdef CONFIG_HIGHMEM
+ if (zone_idx(zone) == ZONE_HIGHMEM) {
+ if (__zones_online_to(end_pfn, first_page, nr_pages))
+ return sprintf(buf, "%s %s\n",
+ zone->name, (zone + 1)->name);
+ }
+#else
+ if (zone_idx(zone) == ZONE_NORMAL) {
+ if (__zones_online_to(end_pfn, first_page, nr_pages))
+ return sprintf(buf, "%s %s\n",
+ zone->name, (zone + 1)->name);
+ }
+#endif
+
+ if (zone_idx(zone) == ZONE_MOVABLE) {
+ if (!pfn_valid(start_pfn - nr_pages))
+ return sprintf(buf, "%s %s\n",
+ zone->name, (zone - 1)->name);
+ zone_prev = page_zone(first_page - nr_pages);
+ if (zone_idx(zone_prev) != ZONE_MOVABLE)
+ return sprintf(buf, "%s %s\n",
+ zone->name, (zone - 1)->name);
+ }
+
+ return sprintf(buf, "%s\n", zone->name);
+}
+
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);
static DEVICE_ATTR(removable, 0444, show_mem_removable, NULL);
+static DEVICE_ATTR(zones_online_to, 0444, show_zones_online_to, NULL);
/*
* Block size attribute stuff
@@ -523,6 +584,7 @@ static struct attribute *memory_memblk_attrs[] = {
&dev_attr_state.attr,
&dev_attr_phys_device.attr,
&dev_attr_removable.attr,
+ &dev_attr_zones_online_to.attr,
NULL
};
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d9524c4..8f1a419 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -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);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 2ff8c23..29d8693 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -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;
--
1.8.1.2
.
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