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Commit 01b0f197 authored by Toshi Kani's avatar Toshi Kani Committed by Linus Torvalds
Browse files

cpu/mem hotplug: add try_online_node() for cpu_up() 



cpu_up() has #ifdef CONFIG_MEMORY_HOTPLUG code blocks, which call
mem_online_node() to put its node online if offlined and then call
build_all_zonelists() to initialize the zone list.

These steps are specific to memory hotplug, and should be managed in
mm/memory_hotplug.c.  lock_memory_hotplug() should also be held for the
whole steps.

For this reason, this patch replaces mem_online_node() with
try_online_node(), which performs the whole steps with
lock_memory_hotplug() held.  try_online_node() is named after
try_offline_node() as they have similar purpose.

There is no functional change in this patch.

Signed-off-by: default avatarToshi Kani <toshi.kani@hp.com>
Reviewed-by: default avatarYasuaki 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 309d0b39

include/linux/memory_hotplug.h

+7 −1
Original line number Diff line number Diff line
@@ -94,6 +94,8 @@ extern void __online_page_set_limits(struct page *page); 
extern void __online_page_increment_counters(struct page *page);

extern void __online_page_free(struct page *page);



extern int try_online_node(int nid);



#ifdef CONFIG_MEMORY_HOTREMOVE

extern bool is_pageblock_removable_nolock(struct page *page);

extern int arch_remove_memory(u64 start, u64 size);
@@ -225,6 +227,11 @@ static inline void register_page_bootmem_info_node(struct pglist_data *pgdat) 
{

}



static inline int try_online_node(int nid)

{

	return 0;

}



static inline void lock_memory_hotplug(void) {}

static inline void unlock_memory_hotplug(void) {}
@@ -256,7 +263,6 @@ static inline void remove_memory(int nid, u64 start, u64 size) {} 


extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,

		void *arg, int (*func)(struct memory_block *, void *));

extern int mem_online_node(int nid);

extern int add_memory(int nid, u64 start, u64 size);

extern int arch_add_memory(int nid, u64 start, u64 size);

extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);

kernel/cpu.c

+3 −26
Original line number Diff line number Diff line
@@ -437,11 +437,6 @@ int cpu_up(unsigned int cpu) 
{

	int err = 0;



#ifdef	CONFIG_MEMORY_HOTPLUG

	int nid;

	pg_data_t	*pgdat;

#endif



	if (!cpu_possible(cpu)) {

		printk(KERN_ERR "can't online cpu %d because it is not "

			"configured as may-hotadd at boot time\n", cpu);
@@ -452,27 +447,9 @@ int cpu_up(unsigned int cpu) 
		return -EINVAL;

	}



#ifdef	CONFIG_MEMORY_HOTPLUG

	nid = cpu_to_node(cpu);

	if (!node_online(nid)) {

		err = mem_online_node(nid);

	err = try_online_node(cpu_to_node(cpu));

	if (err)

		return err;

	}



	pgdat = NODE_DATA(nid);

	if (!pgdat) {

		printk(KERN_ERR

			"Can't online cpu %d due to NULL pgdat\n", cpu);

		return -ENOMEM;

	}



	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {

		mutex_lock(&zonelists_mutex);

		build_all_zonelists(NULL, NULL);

		mutex_unlock(&zonelists_mutex);

	}

#endif



	cpu_maps_update_begin();

mm/memory_hotplug.c

+14 −2
Original line number Diff line number Diff line
@@ -1043,17 +1043,23 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 
}





/*

/**

 * try_online_node - online a node if offlined

 *

 * called by cpu_up() to online a node without onlined memory.

 */

int mem_online_node(int nid)

int try_online_node(int nid)

{

	pg_data_t	*pgdat;

	int	ret;



	if (node_online(nid))

		return 0;



	lock_memory_hotplug();

	pgdat = hotadd_new_pgdat(nid, 0);

	if (!pgdat) {

		pr_err("Cannot online node %d due to NULL pgdat\n", nid);

		ret = -ENOMEM;

		goto out;

	}
@@ -1061,6 +1067,12 @@ int mem_online_node(int nid) 
	ret = register_one_node(nid);

	BUG_ON(ret);



	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {

		mutex_lock(&zonelists_mutex);

		build_all_zonelists(NULL, NULL);

		mutex_unlock(&zonelists_mutex);

	}



out:

	unlock_memory_hotplug();

	return ret;