As Yasuaki Ishimatsu described the check here is not enough
if memory has hole as follows:
PFN 0x00 0xd0 0xe0 0xf0
+-------------+-------------+-------------+
zone type | Normal | hole | Normal |
+-------------+-------------+-------------+
In this case, the check can't guarantee that this is "the last
block of memory".
The check of ZONE_MOVABLE has the same problem.
Signed-off-by: Zhang Zhen <zhenzhang.zhang@xxxxxxxxxx>
---
drivers/base/memory.c | 36 ++++++------------------------------
1 file changed, 6 insertions(+), 30 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index ccaf37c..0fc1d25 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -374,20 +374,6 @@ static ssize_t show_phys_device(struct device *dev,
}
#ifdef CONFIG_MEMORY_HOTREMOVE
-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)
{
@@ -407,28 +393,18 @@ static ssize_t show_zones_online_to(struct device *dev,
zone = page_zone(first_page);
-#ifdef CONFIG_HIGHMEM
- if (zone_idx(zone) == ZONE_HIGHMEM) {
- if (__zones_online_to(end_pfn, first_page, nr_pages))
+ 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);
}
-#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)
+ /*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);
+ zone->name, (zone - 1)->name);
}
return sprintf(buf, "%s\n", zone->name);
--
1.8.1.4
.
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