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: Zhang 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index a2e13e2..7c5d871 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -373,6 +373,45 @@
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 @@
&dev_attr_state.attr,
&dev_attr_phys_device.attr,
&dev_attr_removable.attr,
+#ifdef CONFIG_MEMORY_HOTREMOVE
+ &dev_attr_valid_zones.attr,
+#endif
NULL
};