[PATCH v2 6/8] mm/memory_hotplug: Remove memory block devices before arch_remove_memory()

David Hildenbrand
2019-05-07T18:38:02Z

Let's factor out removing of memory block devices, which is only
necessary for memory added via add_memory() and friends that created
memory block devices. Remove the devices before calling
arch_remove_memory().

This finishes factoring out memory block device handling from
arch_add_memory() and arch_remove_memory().

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "mike.travis@hpe.com" <mike.travis@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Mark Brown <broonie@kernel.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
drivers/base/memory.c | 39 +++++++++++++++++++--------------------
drivers/base/node.c | 11 ++++++-----
include/linux/memory.h | 2 +-
include/linux/node.h | 6 ++----
mm/memory_hotplug.c | 5 +++--
5 files changed, 31 insertions(+), 32 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 862c202a18ca..47ff49058d1f 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -756,32 +756,31 @@ int hotplug_memory_register(unsigned long start, unsigned long size)
return ret;
}

-static int remove_memory_section(struct mem_section *section)
+/*
+ * Remove memory block devices for the given memory area. Start and size
+ * have to be aligned to memory block granularity. Memory block devices
+ * have to be offline.
+ */
+void hotplug_memory_unregister(unsigned long start, unsigned long size)
{
+ unsigned long block_nr_pages = memory_block_size_bytes() >> PAGE_SHIFT;
+ unsigned long start_pfn = PFN_DOWN(start);
+ unsigned long end_pfn = start_pfn + (size >> PAGE_SHIFT);
struct memory_block *mem;
+ unsigned long pfn;

- if (WARN_ON_ONCE(!present_section(section)))
- return;
+ BUG_ON(!IS_ALIGNED(start, memory_block_size_bytes()));
+ BUG_ON(!IS_ALIGNED(size, memory_block_size_bytes()));

mutex_lock(&mem_sysfs_mutex);
-
- /*
- * Some users of the memory hotplug do not want/need memblock to
- * track all sections. Skip over those.
- */
- mem = find_memory_block(section);
- if (!mem)
- goto out_unlock;
-
- unregister_mem_sect_under_nodes(mem, __section_nr(section));
-
- mem->section_count--;
- if (mem->section_count == 0)
+ for (pfn = start_pfn; pfn != end_pfn; pfn += block_nr_pages) {
+ mem = find_memory_block(__pfn_to_section(pfn));
+ if (!mem)
+ continue;
+ mem->section_count = 0;
+ unregister_memory_block_under_nodes(mem);
unregister_memory(mem);
- else
- put_device(&mem->dev);
-
-out_unlock:
+ }
mutex_unlock(&mem_sysfs_mutex);
}

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 8598fcbd2a17..04fdfa99b8bc 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -801,9 +801,10 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg)
return 0;
}

-/* unregister memory section under all nodes that it spans */
-int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
- unsigned long phys_index)
+/*
+ * Unregister memory block device under all nodes that it spans.
+ */
+int unregister_memory_block_under_nodes(struct memory_block *mem_blk)
{
NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
unsigned long pfn, sect_start_pfn, sect_end_pfn;
@@ -816,8 +817,8 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
return -ENOMEM;
nodes_clear(*unlinked_nodes);

- sect_start_pfn = section_nr_to_pfn(phys_index);
- sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
+ 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;

diff --git a/include/linux/memory.h b/include/linux/memory.h
index 95505fbb5f85..aa236c2a0466 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -112,7 +112,7 @@ extern void unregister_memory_notifier(struct notifier_block *nb);
extern int register_memory_isolate_notifier(struct notifier_block *nb);
extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
int hotplug_memory_register(unsigned long start, unsigned long size);
-extern void unregister_memory_section(struct mem_section *);
+void hotplug_memory_unregister(unsigned long start, unsigned long size);
extern int memory_dev_init(void);
extern int memory_notify(unsigned long val, void *v);
extern int memory_isolate_notify(unsigned long val, void *v);
diff --git a/include/linux/node.h b/include/linux/node.h
index 1a557c589ecb..02a29e71b175 100644
--- a/include/linux/node.h
+++ b/include/linux/node.h
@@ -139,8 +139,7 @@ extern int register_cpu_under_node(unsigned int cpu, unsigned int nid);
extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid);
extern int register_mem_sect_under_node(struct memory_block *mem_blk,
void *arg);
-extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
- unsigned long phys_index);
+extern int unregister_memory_block_under_nodes(struct memory_block *mem_blk);

extern int register_memory_node_under_compute_node(unsigned int mem_nid,
unsigned int cpu_nid,
@@ -176,8 +175,7 @@ static inline int register_mem_sect_under_node(struct memory_block *mem_blk,
{
return 0;
}
-static inline int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
- unsigned long phys_index)
+static inline int unregister_memory_block_under_nodes(struct memory_block *mem_blk)
{
return 0;
}
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 107f72952347..527fe4f9c620 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -519,8 +519,6 @@ static void __remove_section(struct zone *zone, struct mem_section *ms,
if (WARN_ON_ONCE(!valid_section(ms)))
return;

- unregister_memory_section(ms);
-
scn_nr = __section_nr(ms);
start_pfn = section_nr_to_pfn((unsigned long)scn_nr);
__remove_zone(zone, start_pfn);
@@ -1844,6 +1842,9 @@ void __ref __remove_memory(int nid, u64 start, u64 size)
memblock_free(start, size);
memblock_remove(start, size);

+ /* remove memory block devices before removing memory */
+ hotplug_memory_unregister(start, size);
+
arch_remove_memory(nid, start, size, NULL);
__release_memory_resource(start, size);

--
2.20.1