The patch titled
Subject: mm/memory_hotplug.c: call register_mem_sect_under_node()
has been added to the -mm tree. Its filename is
mm-memory_hotplug-call-register_mem_sect_under_node.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-call-register_mem_sect_under_node.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-call-register_mem_sect_under_node.patch
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------------------------------------------------------
From: Oscar Salvador <osalvador@xxxxxxx>
Subject: mm/memory_hotplug.c: call register_mem_sect_under_node()
When hotplugging memory, it is possible that two calls are being made to
register_mem_sect_under_node().
One comes from __add_section()->hotplug_memory_register() and the other
from add_memory_resource()->link_mem_sections() if we had to register a
new node.
In case we had to register a new node, hotplug_memory_register() will only
handle/allocate the memory_block's since register_mem_sect_under_node()
will return right away because the node it is not online yet.
I think it is better if we leave hotplug_memory_register() to
handle/allocate only memory_block's and make link_mem_sections() to call
register_mem_sect_under_node().
So this patch removes the call to register_mem_sect_under_node() from
hotplug_memory_register(), and moves the call to link_mem_sections() out
of the condition, so it will always be called. In this way we only have
one place where the memory sections are registered.
Link: http://lkml.kernel.org/r/20180622111839.10071-3-osalvador@xxxxxxxxxxxxxxxxxx
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Tested-by: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
Tested-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/memory.c | 2 --
mm/memory_hotplug.c | 32 +++++++++++---------------------
2 files changed, 11 insertions(+), 23 deletions(-)
diff -puN drivers/base/memory.c~mm-memory_hotplug-call-register_mem_sect_under_node drivers/base/memory.c
--- a/drivers/base/memory.c~mm-memory_hotplug-call-register_mem_sect_under_node
+++ a/drivers/base/memory.c
@@ -736,8 +736,6 @@ int hotplug_memory_register(int nid, str
mem->section_count++;
}
- if (mem->section_count == sections_per_block)
- ret = register_mem_sect_under_node(mem, nid, false);
out:
mutex_unlock(&mem_sysfs_mutex);
return ret;
diff -puN mm/memory_hotplug.c~mm-memory_hotplug-call-register_mem_sect_under_node mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-memory_hotplug-call-register_mem_sect_under_node
+++ a/mm/memory_hotplug.c
@@ -1123,6 +1123,7 @@ int __ref add_memory_resource(int nid, s
u64 start, size;
bool new_node = false;
int ret;
+ unsigned long start_pfn, nr_pages;
start = res->start;
size = resource_size(res);
@@ -1151,34 +1152,23 @@ int __ref add_memory_resource(int nid, s
if (ret < 0)
goto error;
- /* we online node here. we can't roll back from here. */
- node_set_online(nid);
-
if (new_node) {
- unsigned long start_pfn = start >> PAGE_SHIFT;
- unsigned long nr_pages = size >> PAGE_SHIFT;
-
- ret = __register_one_node(nid);
- if (ret)
- goto register_fail;
-
- /*
- * link memory sections under this node. This is already
- * done when creatig memory section in register_new_memory
- * but that depends to have the node registered so offline
- * nodes have to go through register_node.
- * TODO clean up this mess.
- */
- ret = link_mem_sections(nid, start_pfn, nr_pages, false);
-register_fail:
- /*
- * If sysfs file of new node can't create, cpu on the node
+ /* If sysfs file of new node can't be created, cpu on the node
* can't be hot-added. There is no rollback way now.
* So, check by BUG_ON() to catch it reluctantly..
+ * We online node here. We can't roll back from here.
*/
+ node_set_online(nid);
+ ret = __register_one_node(nid);
BUG_ON(ret);
}
+ /* link memory sections under this node.*/
+ start_pfn = start >> PAGE_SHIFT;
+ nr_pages = size >> PAGE_SHIFT;
+ ret = link_mem_sections(nid, start_pfn, nr_pages, false);
+ BUG_ON(ret);
+
/* create new memmap entry */
firmware_map_add_hotplug(start, start + size, "System RAM");
_
Patches currently in -mm which might be from osalvador@xxxxxxx are
mm-memory_hotplug-make-add_memory_resource-use-__try_online_node.patch
mm-memory_hotplug-call-register_mem_sect_under_node.patch
mm-memory_hotplug-make-register_mem_sect_under_node-a-cb-of-walk_memory_range.patch
mm-memory_hotplug-drop-unnecessary-checks-from-register_mem_sect_under_node.patch
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