From 260ae3f7db614a5c4aa4b773599f99adc1d9859e Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 15 Jan 2016 16:56:17 -0800 Subject: [PATCH] mm: skip memory block registration for ZONE_DEVICE Prevent userspace from trying and failing to online ZONE_DEVICE pages which are meant to never be onlined. For example on platforms with a udev rule like the following: SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", ATTR{state}="online" ...will generate futile attempts to online the ZONE_DEVICE sections. Example kernel messages: Built 1 zonelists in Node order, mobility grouping on. Total pages: 1004747 Policy zone: Normal online_pages [mem 0x248000000-0x24fffffff] failed Signed-off-by: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/memory.c | 13 +++++++++++++ include/linux/mm.h | 12 ++++++++++++ 2 files changed, 25 insertions(+) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 619fe584a44c..213456c2b123 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -647,6 +647,13 @@ 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, @@ -657,6 +664,9 @@ 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); @@ -693,6 +703,9 @@ 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); mem = find_memory_block(section); unregister_mem_sect_under_nodes(mem, __section_nr(section)); diff --git a/include/linux/mm.h b/include/linux/mm.h index 0ef5f21735af..d9fe12d45c21 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -674,6 +674,18 @@ static inline enum zone_type page_zonenum(const struct page *page) return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK; } +#ifdef CONFIG_ZONE_DEVICE +static inline bool is_zone_device_page(const struct page *page) +{ + return page_zonenum(page) == ZONE_DEVICE; +} +#else +static inline bool is_zone_device_page(const struct page *page) +{ + return false; +} +#endif + #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) #define SECTION_IN_PAGE_FLAGS #endif