We don't allow to offline memory block devices that belong to multiple
numa nodes. Therefore, such devices can never get removed. It is
sufficient to process a single node when removing the memory block.
Remember for each memory block if it belongs to no, a single, or mixed
nodes, so we can use that information to skip unregistering or print a
warning (essentially a safety net to catch BUGs).
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <raf...@kernel.org>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: David Hildenbrand <da...@redhat.com>
Cc: Stephen Rothwell <s...@canb.auug.org.au>
Cc: Pavel Tatashin <pasha.tatas...@soleen.com>
Cc: Michal Hocko <mho...@suse.com>
Cc: Oscar Salvador <osalva...@suse.de>
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
drivers/base/memory.c | 1 +
drivers/base/node.c | 40 ++++++++++++++++------------------------
include/linux/memory.h | 4 +++-
3 files changed, 20 insertions(+), 25 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 20c39d1bcef8..154d5d4a0779 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -674,6 +674,7 @@ static int init_memory_block(struct memory_block **memory,
mem->state = state;
start_pfn = section_nr_to_pfn(mem->start_section_nr);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
+ mem->nid = NUMA_NO_NODE;
ret = register_memory(mem);
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 75b7e6f6535b..29d27b8d5fda 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -759,8 +759,6 @@ static int register_mem_sect_under_node(struct memory_block
*mem_blk,
int ret, nid = *(int *)arg;
unsigned long pfn, sect_start_pfn, sect_end_pfn;
- mem_blk->nid = nid;
-
sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
sect_end_pfn += PAGES_PER_SECTION - 1;
@@ -789,6 +787,13 @@ static int register_mem_sect_under_node(struct
memory_block *mem_blk,
if (page_nid != nid)
continue;
}
+
+ /* this memory block spans this node */
+ if (mem_blk->nid == NUMA_NO_NODE)
+ mem_blk->nid = nid;
+ else
+ mem_blk->nid = NUMA_NO_NODE - 1;
+
ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj,
&mem_blk->dev.kobj,
kobject_name(&mem_blk->dev.kobj));
@@ -804,32 +809,19 @@ static int register_mem_sect_under_node(struct
memory_block *mem_blk,
}
/*
- * Unregister memory block device under all nodes that it spans.
- * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes).
+ * Unregister a memory block device under the node it spans. Memory blocks
+ * with multiple nodes cannot be offlined and therefore also never be removed.
*/
void unregister_memory_block_under_nodes(struct memory_block *mem_blk)
{
- unsigned long pfn, sect_start_pfn, sect_end_pfn;
- static nodemask_t unlinked_nodes;
-
- nodes_clear(unlinked_nodes);
- sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr);
- sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr);
- for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
- int nid;
+ if (mem_blk->nid == NUMA_NO_NODE ||
+ WARN_ON_ONCE(mem_blk->nid == NUMA_NO_NODE - 1))
+ return;
- nid = get_nid_for_pfn(pfn);
- if (nid < 0)
- continue;
- if (!node_online(nid))
- continue;
- if (node_test_and_set(nid, unlinked_nodes))
- continue;
- sysfs_remove_link(&node_devices[nid]->dev.kobj,
- kobject_name(&mem_blk->dev.kobj));
- sysfs_remove_link(&mem_blk->dev.kobj,
- kobject_name(&node_devices[nid]->dev.kobj));
- }
+ sysfs_remove_link(&node_devices[mem_blk->nid]->dev.kobj,
+ kobject_name(&mem_blk->dev.kobj));
+ sysfs_remove_link(&mem_blk->dev.kobj,
+ kobject_name(&node_devices[mem_blk->nid]->dev.kobj));
}
int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn)
diff --git a/include/linux/memory.h b/include/linux/memory.h
index 02e633f3ede0..c91af10d5fb4 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -33,7 +33,9 @@ struct memory_block {
void *hw; /* optional pointer to fw/hw data */
int (*phys_callback)(struct memory_block *);
struct device dev;
- int nid; /* NID for this memory block */
+ int nid; /* NID for this memory block.
+ - NUMA_NO_NODE: uninitialized
+ - NUMA_NO_NODE - 1: mixed nodes */
};
int arch_get_memory_phys_device(unsigned long start_pfn);
--
2.21.0
