mm/memory_hotplug: Call register_mem_sect_under_node
Subsystems (3)
RFC PATCH 2/3 mm/memory_hotplug: Call register_mem_sect_under_node
From: Oscar Salvador <[email protected]>
When hotpluging 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.
--- drivers/base/memory.c | 2 -- mm/memory_hotplug.c | 40 ++++++++++++++++++---------------------- 2 files changed, 18 insertions(+), 24 deletions(-)
drivers/base/memory.c +0 -2
@@ -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 +18 -22
@@ -1118,6 +1118,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)u64 start, size;bool new_node;int ret; +unsigned long start_pfn, nr_pages; start = res->start; size =resource_size (res);
@@ -1147,34 +1148,21 @@ 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 ; - +/* we online node here. we can't roll back from here. */ +node_set_online (nid); 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 -* can't be hot-added. There is no rollback way now. -* So, check by BUG_ON() to catch it reluctantly.. -*/ -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); +if (ret) + goto register_fail; +/* create new memmap entry */ firmware_map_add_hotplug (start, start + size,"System RAM" );
@@ -1185,6 +1173,14 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) goto out; +register_fail: +/* +* If sysfs file of new node can't create, cpu on the node +* can't be hot-added. There is no rollback way now. +* So, check by BUG_ON() to catch it reluctantly.. +*/ +BUG_ON (ret); + error:/* rollback pgdat allocation and others */ if (new_node)
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2.13.6