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 <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: "[email protected]" <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andrew Banman <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Arun KS <[email protected]>
Cc: Mathieu Malaterre <[email protected]>
Reviewed-by: Dan Williams <[email protected]>
Signed-off-by: David Hildenbrand <[email protected]>
---
drivers/base/memory.c | 37 ++++++++++++++++++-------------------
drivers/base/node.c | 11 ++++++-----
include/linux/memory.h | 2 +-
include/linux/node.h | 6 ++----
mm/memory_hotplug.c | 5 +++--
5 files changed, 30 insertions(+), 31 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 5a0370f0c506..f28efb0bf5c7 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -763,32 +763,31 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
return ret;
}
-void unregister_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 remove_memory_block_devices(unsigned long start, unsigned long size)
{
+ const int start_block_id = pfn_to_block_id(PFN_DOWN(start));
+ const int end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
struct memory_block *mem;
+ int block_id;
- if (WARN_ON_ONCE(!present_section(section)))
+ if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
+ !IS_ALIGNED(size, memory_block_size_bytes())))
return;
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 (block_id = start_block_id; block_id != end_block_id; block_id++) {
+ mem = find_memory_block_by_id(block_id, NULL);
+ if (WARN_ON_ONCE(!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 db3e8567f900..f26a5417ec5d 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 create_memory_block_devices(unsigned long start, unsigned long size);
-extern void unregister_memory_section(struct mem_section *);
+void remove_memory_block_devices(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 9a92549ef23b..82136c5b4c5f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -520,8 +520,6 @@ 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);
@@ -1845,6 +1843,9 @@ 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 */
+ remove_memory_block_devices(start, size);
+
arch_remove_memory(nid, start, size, NULL);
__release_memory_resource(start, size);
--
2.20.1
On Mon, May 27, 2019 at 01:11:50PM +0200, David Hildenbrand wrote:
>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 <[email protected]>
>Cc: "Rafael J. Wysocki" <[email protected]>
>Cc: David Hildenbrand <[email protected]>
>Cc: "[email protected]" <[email protected]>
>Cc: Andrew Morton <[email protected]>
>Cc: Andrew Banman <[email protected]>
>Cc: Ingo Molnar <[email protected]>
>Cc: Alex Deucher <[email protected]>
>Cc: "David S. Miller" <[email protected]>
>Cc: Mark Brown <[email protected]>
>Cc: Chris Wilson <[email protected]>
>Cc: Oscar Salvador <[email protected]>
>Cc: Jonathan Cameron <[email protected]>
>Cc: Michal Hocko <[email protected]>
>Cc: Pavel Tatashin <[email protected]>
>Cc: Arun KS <[email protected]>
>Cc: Mathieu Malaterre <[email protected]>
>Reviewed-by: Dan Williams <[email protected]>
>Signed-off-by: David Hildenbrand <[email protected]>
>---
> drivers/base/memory.c | 37 ++++++++++++++++++-------------------
> drivers/base/node.c | 11 ++++++-----
> include/linux/memory.h | 2 +-
> include/linux/node.h | 6 ++----
> mm/memory_hotplug.c | 5 +++--
> 5 files changed, 30 insertions(+), 31 deletions(-)
>
>diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>index 5a0370f0c506..f28efb0bf5c7 100644
>--- a/drivers/base/memory.c
>+++ b/drivers/base/memory.c
>@@ -763,32 +763,31 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
> return ret;
> }
>
>-void unregister_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 remove_memory_block_devices(unsigned long start, unsigned long size)
> {
>+ const int start_block_id = pfn_to_block_id(PFN_DOWN(start));
>+ const int end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
> struct memory_block *mem;
>+ int block_id;
>
>- if (WARN_ON_ONCE(!present_section(section)))
>+ if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
>+ !IS_ALIGNED(size, memory_block_size_bytes())))
> return;
>
> 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 (block_id = start_block_id; block_id != end_block_id; block_id++) {
>+ mem = find_memory_block_by_id(block_id, NULL);
>+ if (WARN_ON_ONCE(!mem))
>+ continue;
>+ mem->section_count = 0;
Is this step necessary?
>+ 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 db3e8567f900..f26a5417ec5d 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 create_memory_block_devices(unsigned long start, unsigned long size);
>-extern void unregister_memory_section(struct mem_section *);
>+void remove_memory_block_devices(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 9a92549ef23b..82136c5b4c5f 100644
>--- a/mm/memory_hotplug.c
>+++ b/mm/memory_hotplug.c
>@@ -520,8 +520,6 @@ 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);
>@@ -1845,6 +1843,9 @@ 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 */
>+ remove_memory_block_devices(start, size);
>+
> arch_remove_memory(nid, start, size, NULL);
> __release_memory_resource(start, size);
>
>--
>2.20.1
--
Wei Yang
Help you, Help me
On 05.06.19 00:07, Wei Yang wrote:
> On Mon, May 27, 2019 at 01:11:50PM +0200, David Hildenbrand wrote:
>> 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 <[email protected]>
>> Cc: "Rafael J. Wysocki" <[email protected]>
>> Cc: David Hildenbrand <[email protected]>
>> Cc: "[email protected]" <[email protected]>
>> Cc: Andrew Morton <[email protected]>
>> Cc: Andrew Banman <[email protected]>
>> Cc: Ingo Molnar <[email protected]>
>> Cc: Alex Deucher <[email protected]>
>> Cc: "David S. Miller" <[email protected]>
>> Cc: Mark Brown <[email protected]>
>> Cc: Chris Wilson <[email protected]>
>> Cc: Oscar Salvador <[email protected]>
>> Cc: Jonathan Cameron <[email protected]>
>> Cc: Michal Hocko <[email protected]>
>> Cc: Pavel Tatashin <[email protected]>
>> Cc: Arun KS <[email protected]>
>> Cc: Mathieu Malaterre <[email protected]>
>> Reviewed-by: Dan Williams <[email protected]>
>> Signed-off-by: David Hildenbrand <[email protected]>
>> ---
>> drivers/base/memory.c | 37 ++++++++++++++++++-------------------
>> drivers/base/node.c | 11 ++++++-----
>> include/linux/memory.h | 2 +-
>> include/linux/node.h | 6 ++----
>> mm/memory_hotplug.c | 5 +++--
>> 5 files changed, 30 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
>> index 5a0370f0c506..f28efb0bf5c7 100644
>> --- a/drivers/base/memory.c
>> +++ b/drivers/base/memory.c
>> @@ -763,32 +763,31 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
>> return ret;
>> }
>>
>> -void unregister_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 remove_memory_block_devices(unsigned long start, unsigned long size)
>> {
>> + const int start_block_id = pfn_to_block_id(PFN_DOWN(start));
>> + const int end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
>> struct memory_block *mem;
>> + int block_id;
>>
>> - if (WARN_ON_ONCE(!present_section(section)))
>> + if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
>> + !IS_ALIGNED(size, memory_block_size_bytes())))
>> return;
>>
>> 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 (block_id = start_block_id; block_id != end_block_id; block_id++) {
>> + mem = find_memory_block_by_id(block_id, NULL);
>> + if (WARN_ON_ONCE(!mem))
>> + continue;
>> + mem->section_count = 0;
>
> Is this step necessary?
It's what the previous code does, it might not be - I'll leave it like
that for now. As mentioned in another reply, I might remove the
section_count completely, eventually.
--
Thanks,
David / dhildenb
On Mon 27-05-19 13:11:50, David Hildenbrand wrote:
> 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().
OK, this makes sense again. Just a nit. Calling find_memory_block_by_id
for each memory block looks a bit suboptimal, especially when we are
removing consequent physical memblocks. I have to confess that I do not
know how expensive is the search and I also expect that there won't be
that many memblocks in the removed range anyway as large setups have
large memblocks.
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: "[email protected]" <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Andrew Banman <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Alex Deucher <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Mark Brown <[email protected]>
> Cc: Chris Wilson <[email protected]>
> Cc: Oscar Salvador <[email protected]>
> Cc: Jonathan Cameron <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Pavel Tatashin <[email protected]>
> Cc: Arun KS <[email protected]>
> Cc: Mathieu Malaterre <[email protected]>
> Reviewed-by: Dan Williams <[email protected]>
> Signed-off-by: David Hildenbrand <[email protected]>
Other than that looks good to me.
Acked-by: Michal Hocko <[email protected]>
> ---
> drivers/base/memory.c | 37 ++++++++++++++++++-------------------
> drivers/base/node.c | 11 ++++++-----
> include/linux/memory.h | 2 +-
> include/linux/node.h | 6 ++----
> mm/memory_hotplug.c | 5 +++--
> 5 files changed, 30 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 5a0370f0c506..f28efb0bf5c7 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -763,32 +763,31 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
> return ret;
> }
>
> -void unregister_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 remove_memory_block_devices(unsigned long start, unsigned long size)
> {
> + const int start_block_id = pfn_to_block_id(PFN_DOWN(start));
> + const int end_block_id = pfn_to_block_id(PFN_DOWN(start + size));
> struct memory_block *mem;
> + int block_id;
>
> - if (WARN_ON_ONCE(!present_section(section)))
> + if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
> + !IS_ALIGNED(size, memory_block_size_bytes())))
> return;
>
> 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 (block_id = start_block_id; block_id != end_block_id; block_id++) {
> + mem = find_memory_block_by_id(block_id, NULL);
> + if (WARN_ON_ONCE(!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 db3e8567f900..f26a5417ec5d 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 create_memory_block_devices(unsigned long start, unsigned long size);
> -extern void unregister_memory_section(struct mem_section *);
> +void remove_memory_block_devices(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 9a92549ef23b..82136c5b4c5f 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -520,8 +520,6 @@ 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);
> @@ -1845,6 +1843,9 @@ 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 */
> + remove_memory_block_devices(start, size);
> +
> arch_remove_memory(nid, start, size, NULL);
> __release_memory_resource(start, size);
>
> --
> 2.20.1
>
--
Michal Hocko
SUSE Labs
On 01.07.19 10:41, Michal Hocko wrote:
> On Mon 27-05-19 13:11:50, David Hildenbrand wrote:
>> 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().
>
> OK, this makes sense again. Just a nit. Calling find_memory_block_by_id
> for each memory block looks a bit suboptimal, especially when we are
> removing consequent physical memblocks. I have to confess that I do not
> know how expensive is the search and I also expect that there won't be
> that many memblocks in the removed range anyway as large setups have
> large memblocks.
>
The devices are not allocated sequentially, so there is no easy way to
look them up.
There is a comment for find_memory_block():
"For now, we have a linear search to go find the appropriate
memory_block corresponding to a particular phys_index. If this gets to
be a real problem, we can always use a radix tree or something here."
So if this becomes a problem, we need a separate data structure to speed
up the lookup. (IOW, this was already the same in the old code)
Thanks!
--
Thanks,
David / dhildenb