Commit 4edd7cef authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, hotplug: avoid compiling memory hotremove functions when disabled 



__remove_pages() is only necessary for CONFIG_MEMORY_HOTREMOVE.  PowerPC
pseries will return -EOPNOTSUPP if unsupported.

Adding an #ifdef causes several other functions it depends on to also
become unnecessary, which saves in .text when disabled (it's disabled in
most defconfigs besides powerpc, including x86).  remove_memory_block()
becomes static since it is not referenced outside of
drivers/base/memory.c.

Build tested on x86 and powerpc with CONFIG_MEMORY_HOTREMOVE both enabled
and disabled.

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Acked-by: default avatarToshi Kani <toshi.kani@hp.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fe74ebb1

arch/powerpc/platforms/pseries/hotplug-memory.c

+12 −0
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ unsigned long memory_block_size_bytes(void) 
	return get_memblock_size();

}



#ifdef CONFIG_MEMORY_HOTREMOVE

static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)

{

	unsigned long start, start_pfn;
@@ -153,6 +154,17 @@ static int pseries_remove_memory(struct device_node *np) 
	ret = pseries_remove_memblock(base, lmb_size);

	return ret;

}

#else

static inline int pseries_remove_memblock(unsigned long base,

					  unsigned int memblock_size)

{

	return -EOPNOTSUPP;

}

static inline int pseries_remove_memory(struct device_node *np)

{

	return -EOPNOTSUPP;

}

#endif /* CONFIG_MEMORY_HOTREMOVE */



static int pseries_add_memory(struct device_node *np)

{

drivers/base/memory.c

+23 −21
Original line number Diff line number Diff line
@@ -93,16 +93,6 @@ int register_memory(struct memory_block *memory) 
	return error;

}



static void

unregister_memory(struct memory_block *memory)

{

	BUG_ON(memory->dev.bus != &memory_subsys);



	/* drop the ref. we got in remove_memory_block() */

	kobject_put(&memory->dev.kobj);

	device_unregister(&memory->dev);

}



unsigned long __weak memory_block_size_bytes(void)

{

	return MIN_MEMORY_BLOCK_SIZE;
@@ -637,8 +627,28 @@ static int add_memory_section(int nid, struct mem_section *section, 
	return ret;

}



int remove_memory_block(unsigned long node_id, struct mem_section *section,

		int phys_device)

/*

 * need an interface for the VM to add new memory regions,

 * but without onlining it.

 */

int register_new_memory(int nid, struct mem_section *section)

{

	return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG);

}



#ifdef CONFIG_MEMORY_HOTREMOVE

static void

unregister_memory(struct memory_block *memory)

{

	BUG_ON(memory->dev.bus != &memory_subsys);



	/* drop the ref. we got in remove_memory_block() */

	kobject_put(&memory->dev.kobj);

	device_unregister(&memory->dev);

}



static int remove_memory_block(unsigned long node_id,

			       struct mem_section *section, int phys_device)

{

	struct memory_block *mem;
@@ -661,15 +671,6 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section, 
	return 0;

}



/*

 * need an interface for the VM to add new memory regions,

 * but without onlining it.

 */

int register_new_memory(int nid, struct mem_section *section)

{

	return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG);

}



int unregister_memory_section(struct mem_section *section)

{

	if (!present_section(section))
@@ -677,6 +678,7 @@ int unregister_memory_section(struct mem_section *section) 


	return remove_memory_block(0, section, 0);

}

#endif /* CONFIG_MEMORY_HOTREMOVE */



/*

 * offline one memory block. If the memory block has been offlined, do nothing.

include/linux/memory.h

+2 −1
Original line number Diff line number Diff line
@@ -115,9 +115,10 @@ extern void unregister_memory_notifier(struct notifier_block *nb); 
extern int register_memory_isolate_notifier(struct notifier_block *nb);

extern void unregister_memory_isolate_notifier(struct notifier_block *nb);

extern int register_new_memory(int, struct mem_section *);

#ifdef CONFIG_MEMORY_HOTREMOVE

extern int unregister_memory_section(struct mem_section *);

#endif

extern int memory_dev_init(void);

extern int remove_memory_block(unsigned long, struct mem_section *, int);

extern int memory_notify(unsigned long val, void *v);

extern int memory_isolate_notify(unsigned long val, void *v);

extern struct memory_block *find_memory_block_hinted(struct mem_section *,

include/linux/memory_hotplug.h

+2 −2
Original line number Diff line number Diff line
@@ -97,13 +97,13 @@ extern void __online_page_free(struct page *page); 
#ifdef CONFIG_MEMORY_HOTREMOVE

extern bool is_pageblock_removable_nolock(struct page *page);

extern int arch_remove_memory(u64 start, u64 size);

extern int __remove_pages(struct zone *zone, unsigned long start_pfn,

	unsigned long nr_pages);

#endif /* CONFIG_MEMORY_HOTREMOVE */



/* reasonably generic interface to expand the physical pages in a zone  */

extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn,

	unsigned long nr_pages);

extern int __remove_pages(struct zone *zone, unsigned long start_pfn,

	unsigned long nr_pages);



#ifdef CONFIG_NUMA

extern int memory_add_physaddr_to_nid(u64 start);

mm/memory_hotplug.c

+35 −33
Original line number Diff line number Diff line
@@ -436,6 +436,40 @@ static int __meminit __add_section(int nid, struct zone *zone, 
	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));

}



/*

 * Reasonably generic function for adding memory.  It is

 * expected that archs that support memory hotplug will

 * call this function after deciding the zone to which to

 * add the new pages.

 */

int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,

			unsigned long nr_pages)

{

	unsigned long i;

	int err = 0;

	int start_sec, end_sec;

	/* during initialize mem_map, align hot-added range to section */

	start_sec = pfn_to_section_nr(phys_start_pfn);

	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);



	for (i = start_sec; i <= end_sec; i++) {

		err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);



		/*

		 * EEXIST is finally dealt with by ioresource collision

		 * check. see add_memory() => register_memory_resource()

		 * Warning will be printed if there is collision.

		 */

		if (err && (err != -EEXIST))

			break;

		err = 0;

	}



	return err;

}

EXPORT_SYMBOL_GPL(__add_pages);



#ifdef CONFIG_MEMORY_HOTREMOVE

/* find the smallest valid pfn in the range [start_pfn, end_pfn) */

static int find_smallest_section_pfn(int nid, struct zone *zone,

				     unsigned long start_pfn,
@@ -658,39 +692,6 @@ static int __remove_section(struct zone *zone, struct mem_section *ms) 
	return 0;

}



/*

 * Reasonably generic function for adding memory.  It is

 * expected that archs that support memory hotplug will

 * call this function after deciding the zone to which to

 * add the new pages.

 */

int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,

			unsigned long nr_pages)

{

	unsigned long i;

	int err = 0;

	int start_sec, end_sec;

	/* during initialize mem_map, align hot-added range to section */

	start_sec = pfn_to_section_nr(phys_start_pfn);

	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);



	for (i = start_sec; i <= end_sec; i++) {

		err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);



		/*

		 * EEXIST is finally dealt with by ioresource collision

		 * check. see add_memory() => register_memory_resource()

		 * Warning will be printed if there is collision.

		 */

		if (err && (err != -EEXIST))

			break;

		err = 0;

	}



	return err;

}

EXPORT_SYMBOL_GPL(__add_pages);



/**

 * __remove_pages() - remove sections of pages from a zone

 * @zone: zone from which pages need to be removed
@@ -733,6 +734,7 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 
	return ret;

}

EXPORT_SYMBOL_GPL(__remove_pages);

#endif /* CONFIG_MEMORY_HOTREMOVE */



int set_online_page_callback(online_page_callback_t callback)

{

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