mm/memory_hotplug.c: call register_mem_sect_under_node() (d5b6f6a3) · Commits · 戴 / test

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:

Oscar Salvador <osalvador@suse.de> Reviewed-by:

Pavel Tatashin <pasha.tatashin@oracle.com> Tested-by:

Reza Arbab <arbab@linux.vnet.ibm.com> Tested-by:

Jonathan 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:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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");

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