mm, memory-hotplug: dynamic configure movable memory and portion memory

Add online_movable and online_kernel for logic memory hotplug.  This is
the dynamic version of "movablecore" & "kernelcore".

We have the same reason to introduce it as to introduce "movablecore" &
"kernelcore".  It has the same motive as "movablecore" & "kernelcore", but
it is dynamic/running-time:

o We can configure memory as kernelcore or movablecore after boot.

  Userspace workload is increased, we need more hugepage, we can't use
  "online_movable" to add memory and allow the system use more
  THP(transparent-huge-page), vice-verse when kernel workload is increase.

  Also help for virtualization to dynamic configure host/guest's memory,
  to save/(reduce waste) memory.

  Memory capacity on Demand

o When a new node is physically online after boot, we need to use
  "online_movable" or "online_kernel" to configure/portion it as we
  expected when we logic-online it.

  This configuration also helps for physically-memory-migrate.

o all benefit as the same as existed "movablecore" & "kernelcore".

o Preparing for movable-node, which is very important for power-saving,
  hardware partitioning and high-available-system(hardware fault
  management).

(Note, we don't introduce movable-node here.)

Action behavior:
When a memoryblock/memorysection is onlined by "online_movable", the kernel
will not have directly reference to the page of the memoryblock,
thus we can remove that memory any time when needed.

When it is online by "online_kernel", the kernel can use it.
When it is online by "online", the zone type doesn't changed.

Current constraints:
Only the memoryblock which is adjacent to the ZONE_MOVABLE
can be online from ZONE_NORMAL to ZONE_MOVABLE.

[akpm@linux-foundation.org: use min_t, cleanups]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 11 deletions

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 7eb1211ab688..987604d56c83 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -254,7 +254,7 @@ static bool pages_correctly_reserved(unsigned long start_pfn,
  * OK to have direct references to sparsemem variables in here.
  */
 static int
-memory_block_action(unsigned long phys_index, unsigned long action)
+memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
 {
         unsigned long start_pfn;
         unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
@@ -269,7 +269,7 @@ memory_block_action(unsigned long phys_index, unsigned long action)
                         if (!pages_correctly_reserved(start_pfn, nr_pages))
                                 return -EBUSY;
 
-                        ret = online_pages(start_pfn, nr_pages);
+                        ret = online_pages(start_pfn, nr_pages, online_type);
                         break;
                 case MEM_OFFLINE:
                         ret = offline_pages(start_pfn, nr_pages);
@@ -284,7 +284,8 @@ memory_block_action(unsigned long phys_index, unsigned long action)
 }
 
 static int __memory_block_change_state(struct memory_block *mem,
-                unsigned long to_state, unsigned long from_state_req)
+                unsigned long to_state, unsigned long from_state_req,
+                int online_type)
 {
         int ret = 0;
 
@@ -296,7 +297,7 @@ static int __memory_block_change_state(struct memory_block *mem,
         if (to_state == MEM_OFFLINE)
                 mem->state = MEM_GOING_OFFLINE;
 
-        ret = memory_block_action(mem->start_section_nr, to_state);
+        ret = memory_block_action(mem->start_section_nr, to_state, online_type);
 
         if (ret) {
                 mem->state = from_state_req;
@@ -319,12 +320,14 @@ out:
 }
 
 static int memory_block_change_state(struct memory_block *mem,
-                unsigned long to_state, unsigned long from_state_req)
+                unsigned long to_state, unsigned long from_state_req,
+                int online_type)
 {
         int ret;
 
         mutex_lock(&mem->state_mutex);
-        ret = __memory_block_change_state(mem, to_state, from_state_req);
+        ret = __memory_block_change_state(mem, to_state, from_state_req,
+                                          online_type);
         mutex_unlock(&mem->state_mutex);
 
         return ret;
@@ -338,10 +341,18 @@ store_mem_state(struct device *dev,
 
         mem = container_of(dev, struct memory_block, dev);
 
-        if (!strncmp(buf, "online", min((int)count, 6)))
-                ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
-        else if(!strncmp(buf, "offline", min((int)count, 7)))
-                ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
+        if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))
+                ret = memory_block_change_state(mem, MEM_ONLINE,
+                                                MEM_OFFLINE, ONLINE_KERNEL);
+        else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
+                ret = memory_block_change_state(mem, MEM_ONLINE,
+                                                MEM_OFFLINE, ONLINE_MOVABLE);
+        else if (!strncmp(buf, "online", min_t(int, count, 6)))
+                ret = memory_block_change_state(mem, MEM_ONLINE,
+                                                MEM_OFFLINE, ONLINE_KEEP);
+        else if(!strncmp(buf, "offline", min_t(int, count, 7)))
+                ret = memory_block_change_state(mem, MEM_OFFLINE,
+                                                MEM_ONLINE, -1);
 
         if (ret)
                 return ret;
@@ -676,7 +687,7 @@ int offline_memory_block(struct memory_block *mem)
 
         mutex_lock(&mem->state_mutex);
         if (mem->state != MEM_OFFLINE)
-                ret = __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
+                ret = __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);
         mutex_unlock(&mem->state_mutex);
 
         return ret;