Re: [PATCH v1 10/10] mm/memory_hotplug: allow online/offline memory by a kernel module

2018-05-23 Thread David Hildenbrand
On 23.05.2018 21:51, Christoph Hellwig wrote:
> On Wed, May 23, 2018 at 05:11:51PM +0200, David Hildenbrand wrote:
>> Kernel modules that want to control how/when memory is onlined/offlined
>> need a proper interface to these functions. Also, for adding memory
>> properly, memory_block_size_bytes is required.
> 
> Which module?  Please send it along with the enabling code.

Hi,

as indicated in the cover letter, it is called "virtio-mem".
I sent it yesterday as a separate series (RFC).

Cover letter: https://lkml.org/lkml/2018/5/23/800
Relevant patch: https://lkml.org/lkml/2018/5/23/803

> 
>> --- a/drivers/base/memory.c
>> +++ b/drivers/base/memory.c
>> @@ -88,6 +88,7 @@ unsigned long __weak memory_block_size_bytes(void)
>>  {
>>  return MIN_MEMORY_BLOCK_SIZE;
>>  }
>> +EXPORT_SYMBOL(memory_block_size_bytes);
> 
>> +EXPORT_SYMBOL(mem_hotplug_begin);
> 
>> +EXPORT_SYMBOL(mem_hotplug_done);
> 
> EXPORT_SYMBOL_GPL for any deep down VM internals, please.
> 

I continued using what was being used for symbols in this file. If there
are not other opinions, I'll switch to EXPORT_SYMBOL_GPL. Thanks!

-- 

Thanks,

David / dhildenb


Re: [PATCH v1 10/10] mm/memory_hotplug: allow online/offline memory by a kernel module

2018-05-23 Thread Christoph Hellwig
On Wed, May 23, 2018 at 05:11:51PM +0200, David Hildenbrand wrote:
> Kernel modules that want to control how/when memory is onlined/offlined
> need a proper interface to these functions. Also, for adding memory
> properly, memory_block_size_bytes is required.

Which module?  Please send it along with the enabling code.

> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -88,6 +88,7 @@ unsigned long __weak memory_block_size_bytes(void)
>  {
>   return MIN_MEMORY_BLOCK_SIZE;
>  }
> +EXPORT_SYMBOL(memory_block_size_bytes);

> +EXPORT_SYMBOL(mem_hotplug_begin);

> +EXPORT_SYMBOL(mem_hotplug_done);

EXPORT_SYMBOL_GPL for any deep down VM internals, please.


[PATCH v1 10/10] mm/memory_hotplug: allow online/offline memory by a kernel module

2018-05-23 Thread David Hildenbrand
Kernel modules that want to control how/when memory is onlined/offlined
need a proper interface to these functions. Also, for adding memory
properly, memory_block_size_bytes is required.

Cc: Greg Kroah-Hartman 
Cc: Andrew Morton 
Cc: Vlastimil Babka 
Cc: Michal Hocko 
Cc: Dan Williams 
Cc: Pavel Tatashin 
Cc: Joonsoo Kim 
Cc: Thomas Gleixner 
Signed-off-by: David Hildenbrand 
---
 drivers/base/memory.c  |  1 +
 include/linux/memory_hotplug.h |  2 ++
 mm/memory_hotplug.c| 27 +--
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c785e4c01b23..0a7c79cfaaf8 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -88,6 +88,7 @@ unsigned long __weak memory_block_size_bytes(void)
 {
return MIN_MEMORY_BLOCK_SIZE;
 }
+EXPORT_SYMBOL(memory_block_size_bytes);
 
 static unsigned long get_memory_block_size(void)
 {
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index ae53017b54df..0e3e48410415 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -97,6 +97,8 @@ extern void __online_page_increment_counters(struct page 
*page);
 extern void __online_page_free(struct page *page);
 
 extern int try_online_node(int nid);
+extern int online_memory_blocks(uint64_t start, uint64_t size);
+extern int offline_memory_blocks(uint64_t start, uint64_t size);
 
 extern bool memhp_auto_online;
 /* If movable_node boot option specified */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3a5845a33910..071976e5e7f6 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -89,12 +89,14 @@ void mem_hotplug_begin(void)
cpus_read_lock();
percpu_down_write(&mem_hotplug_lock);
 }
+EXPORT_SYMBOL(mem_hotplug_begin);
 
 void mem_hotplug_done(void)
 {
percpu_up_write(&mem_hotplug_lock);
cpus_read_unlock();
 }
+EXPORT_SYMBOL(mem_hotplug_done);
 
 /* add this memory to iomem resource */
 static struct resource *register_memory_resource(u64 start, u64 size)
@@ -995,6 +997,7 @@ int __ref online_pages(unsigned long pfn, unsigned long 
nr_pages, int online_typ
memory_notify(MEM_ONLINE, &arg);
return 0;
 }
+EXPORT_SYMBOL(online_pages);
 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 
 static void reset_node_present_pages(pg_data_t *pgdat)
@@ -1124,6 +1127,25 @@ static int online_memory_block(struct memory_block *mem, 
void *arg)
return device_online(&mem->dev);
 }
 
+static int offline_memory_block(struct memory_block *mem, void *arg)
+{
+   return device_offline(&mem->dev);
+}
+
+int online_memory_blocks(uint64_t start, uint64_t size)
+{
+   return walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
+NULL, online_memory_block);
+}
+EXPORT_SYMBOL(online_memory_blocks);
+
+int offline_memory_blocks(uint64_t start, uint64_t size)
+{
+   return walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
+NULL, offline_memory_block);
+}
+EXPORT_SYMBOL(offline_memory_blocks);
+
 static int mark_memory_block_driver_managed(struct memory_block *mem, void 
*arg)
 {
mem->driver_managed = true;
@@ -1212,8 +1234,7 @@ int __ref add_memory_resource(int nid, struct resource 
*res, bool online,
 
/* online pages if requested */
if (online)
-   walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
- NULL, online_memory_block);
+   online_memory_blocks(start, size);
else if (driver_managed)
walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
  NULL, mark_memory_block_driver_managed);
@@ -1312,6 +1333,7 @@ bool is_mem_section_removable(unsigned long start_pfn, 
unsigned long nr_pages)
/* All pageblocks in the memory block are likely to be hot-removable */
return true;
 }
+EXPORT_SYMBOL(is_mem_section_removable);
 
 /*
  * Confirm all pages in a range [start, end) belong to the same zone.
@@ -1774,6 +1796,7 @@ int offline_pages(unsigned long start_pfn, unsigned long 
nr_pages,
 {
return __offline_pages(start_pfn, start_pfn + nr_pages, retry_forever);
 }
+EXPORT_SYMBOL(offline_pages);
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
 /**
-- 
2.17.0