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Commit 260ae3f7 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds
Browse files

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: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 34c0fd54

drivers/base/memory.c

+13 −0
Original line number Diff line number Diff line
@@ -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));

include/linux/mm.h

+12 −0
Original line number Diff line number Diff line
@@ -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