From 1b862aecfbd419cdc4553645bf86d07554279bed Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Thu, 6 Jul 2017 15:37:45 -0700 Subject: mm, memory_hotplug: get rid of is_zone_device_section Device memory hotplug hooks into regular memory hotplug only half way. It needs memory sections to track struct pages but there is no need/desire to associate those sections with memory blocks and export them to the userspace via sysfs because they cannot be onlined anyway. This is currently expressed by for_device argument to arch_add_memory which then makes sure to associate the given memory range with ZONE_DEVICE. register_new_memory then relies on is_zone_device_section to distinguish special memory hotplug from the regular one. While this works now, later patches in this series want to move __add_zone outside of arch_add_memory path so we have to come up with something else. Add want_memblock down the __add_pages path and use it to control whether the section->memblock association should be done. arch_add_memory then just trivially want memblock for everything but for_device hotplug. remove_memory_section doesn't need is_zone_device_section either. We can simply skip all the memblock specific cleanup if there is no memblock for the given section. This shouldn't introduce any functional change. Link: http://lkml.kernel.org/r/20170515085827.16474-5-mhocko@kernel.org Signed-off-by: Michal Hocko Tested-by: Dan Williams Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Balbir Singh Cc: Daniel Kiper Cc: David Rientjes Cc: Heiko Carstens Cc: Igor Mammedov Cc: Jerome Glisse Cc: Joonsoo Kim Cc: Martin Schwidefsky Cc: Mel Gorman Cc: Reza Arbab Cc: Tobias Regnery Cc: Toshi Kani Cc: Vitaly Kuznetsov Cc: Xishi Qiu Cc: Yasuaki Ishimatsu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/memory.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) (limited to 'drivers/base/memory.c') diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 90225ffee501..f8fd562c3f18 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -685,14 +685,6 @@ static int add_memory_block(int base_section_nr) return 0; } -static bool is_zone_device_section(struct mem_section *ms) -{ - struct page *page; - - page = sparse_decode_mem_map(ms->section_mem_map, __section_nr(ms)); - return is_zone_device_page(page); -} - /* * need an interface for the VM to add new memory regions, * but without onlining it. @@ -702,9 +694,6 @@ int register_new_memory(int nid, struct mem_section *section) int ret = 0; struct memory_block *mem; - if (is_zone_device_section(section)) - return 0; - mutex_lock(&mem_sysfs_mutex); mem = find_memory_block(section); @@ -741,11 +730,16 @@ static int remove_memory_section(unsigned long node_id, { struct memory_block *mem; - if (is_zone_device_section(section)) - return 0; - mutex_lock(&mem_sysfs_mutex); + + /* + * Some users of the memory hotplug do not want/need memblock to + * track all sections. Skip over those. + */ mem = find_memory_block(section); + if (!mem) + goto out_unlock; + unregister_mem_sect_under_nodes(mem, __section_nr(section)); mem->section_count--; @@ -754,6 +748,7 @@ static int remove_memory_section(unsigned long node_id, else put_device(&mem->dev); +out_unlock: mutex_unlock(&mem_sysfs_mutex); return 0; } -- cgit v1.2.3