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Commit d5b6f6a3 authored by Oscar Salvador's avatar Oscar Salvador Committed by Linus Torvalds
Browse files

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@techadventures.net


Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarPavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: default avatarReza Arbab <arbab@linux.vnet.ibm.com>
Tested-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b9ff0360

drivers/base/memory.c

+0 −2
Original line number Diff line number Diff line
@@ -736,8 +736,6 @@ int hotplug_memory_register(int nid, struct mem_section *section) 
		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;

mm/memory_hotplug.c

+11 −21
Original line number Diff line number Diff line
@@ -1123,6 +1123,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) 
	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, struct resource *res, bool online) 
	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");