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Commit 7b78d335 authored by Yasunori Goto's avatar Yasunori Goto Committed by Linus Torvalds
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memory hotplug: rearrange memory hotplug notifier 



Current memory notifier has some defects yet.  (Fortunately, nothing uses
it.) This patch is to fix and rearrange for them.

  - Add information of start_pfn, nr_pages, and node id if node status is
    changes from/to memoryless node for callback functions.
    Callbacks can't do anything without those information.
  - Add notification going-online status.
    It is necessary for creating per node structure before the node's
    pages are available.
  - Move GOING_OFFLINE status notification after page isolation.
    It is good place for return memory like cache for callback,
    because returned page is not used again.
  - Make CANCEL events for rollingback when error occurs.
  - Delete MEM_MAPPING_INVALID notification. It will be not used.
  - Fix compile error of (un)register_memory_notifier().

Signed-off-by: default avatarYasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 10020ca2

drivers/base/memory.c

+1 −8
Original line number Diff line number Diff line
@@ -137,7 +137,7 @@ static ssize_t show_mem_state(struct sys_device *dev, char *buf) 
	return len;

}



static inline int memory_notify(unsigned long val, void *v)

int memory_notify(unsigned long val, void *v)

{

	return blocking_notifier_call_chain(&memory_chain, val, v);

}
@@ -183,7 +183,6 @@ memory_block_action(struct memory_block *mem, unsigned long action) 
			break;

		case MEM_OFFLINE:

			mem->state = MEM_GOING_OFFLINE;

			memory_notify(MEM_GOING_OFFLINE, NULL);

			start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;

			ret = remove_memory(start_paddr,

					    PAGES_PER_SECTION << PAGE_SHIFT);
@@ -191,7 +190,6 @@ memory_block_action(struct memory_block *mem, unsigned long action) 
				mem->state = old_state;

				break;

			}

			memory_notify(MEM_MAPPING_INVALID, NULL);

			break;

		default:

			printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
@@ -199,11 +197,6 @@ memory_block_action(struct memory_block *mem, unsigned long action) 
			WARN_ON(1);

			ret = -EINVAL;

	}

	/*

	 * For now, only notify on successful memory operations

	 */

	if (!ret)

		memory_notify(action, NULL);



	return ret;

}

include/linux/memory.h

+15 −12
Original line number Diff line number Diff line
@@ -41,18 +41,15 @@ struct memory_block { 
#define	MEM_ONLINE		(1<<0) /* exposed to userspace */

#define	MEM_GOING_OFFLINE	(1<<1) /* exposed to userspace */

#define	MEM_OFFLINE		(1<<2) /* exposed to userspace */

#define	MEM_GOING_ONLINE	(1<<3)

#define	MEM_CANCEL_ONLINE	(1<<4)

#define	MEM_CANCEL_OFFLINE	(1<<5)



/*

 * All of these states are currently kernel-internal for notifying

 * kernel components and architectures.

 *

 * For MEM_MAPPING_INVALID, all notifier chains with priority >0

 * are called before pfn_to_page() becomes invalid.  The priority=0

 * entry is reserved for the function that actually makes

 * pfn_to_page() stop working.  Any notifiers that want to be called

 * after that should have priority <0.

 */

#define	MEM_MAPPING_INVALID	(1<<3)

struct memory_notify {

	unsigned long start_pfn;

	unsigned long nr_pages;

	int status_change_nid;

};



struct notifier_block;

struct mem_section;
@@ -69,12 +66,18 @@ static inline int register_memory_notifier(struct notifier_block *nb) 
static inline void unregister_memory_notifier(struct notifier_block *nb)

{

}

static inline int memory_notify(unsigned long val, void *v)

{

	return 0;

}

#else

extern int register_memory_notifier(struct notifier_block *nb);

extern void unregister_memory_notifier(struct notifier_block *nb);

extern int register_new_memory(struct mem_section *);

extern int unregister_memory_section(struct mem_section *);

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);

#define CONFIG_MEM_BLOCK_SIZE	(PAGES_PER_SECTION<<PAGE_SHIFT)

mm/memory_hotplug.c

+45 −3
Original line number Diff line number Diff line
@@ -187,7 +187,24 @@ int online_pages(unsigned long pfn, unsigned long nr_pages) 
	unsigned long onlined_pages = 0;

	struct zone *zone;

	int need_zonelists_rebuild = 0;

	int nid;

	int ret;

	struct memory_notify arg;



	arg.start_pfn = pfn;

	arg.nr_pages = nr_pages;

	arg.status_change_nid = -1;



	nid = page_to_nid(pfn_to_page(pfn));

	if (node_present_pages(nid) == 0)

		arg.status_change_nid = nid;



	ret = memory_notify(MEM_GOING_ONLINE, &arg);

	ret = notifier_to_errno(ret);

	if (ret) {

		memory_notify(MEM_CANCEL_ONLINE, &arg);

		return ret;

	}

	/*

	 * This doesn't need a lock to do pfn_to_page().

	 * The section can't be removed here because of the
@@ -222,6 +239,10 @@ int online_pages(unsigned long pfn, unsigned long nr_pages) 
		build_all_zonelists();

	vm_total_pages = nr_free_pagecache_pages();

	writeback_set_ratelimit();



	if (onlined_pages)

		memory_notify(MEM_ONLINE, &arg);



	return 0;

}

#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
@@ -467,8 +488,9 @@ int offline_pages(unsigned long start_pfn, 
{

	unsigned long pfn, nr_pages, expire;

	long offlined_pages;

	int ret, drain, retry_max;

	int ret, drain, retry_max, node;

	struct zone *zone;

	struct memory_notify arg;



	BUG_ON(start_pfn >= end_pfn);

	/* at least, alignment against pageblock is necessary */
@@ -480,11 +502,27 @@ int offline_pages(unsigned long start_pfn, 
	   we assume this for now. .*/

	if (!test_pages_in_a_zone(start_pfn, end_pfn))

		return -EINVAL;



	zone = page_zone(pfn_to_page(start_pfn));

	node = zone_to_nid(zone);

	nr_pages = end_pfn - start_pfn;



	/* set above range as isolated */

	ret = start_isolate_page_range(start_pfn, end_pfn);

	if (ret)

		return ret;

	nr_pages = end_pfn - start_pfn;



	arg.start_pfn = start_pfn;

	arg.nr_pages = nr_pages;

	arg.status_change_nid = -1;

	if (nr_pages >= node_present_pages(node))

		arg.status_change_nid = node;



	ret = memory_notify(MEM_GOING_OFFLINE, &arg);

	ret = notifier_to_errno(ret);

	if (ret)

		goto failed_removal;



	pfn = start_pfn;

	expire = jiffies + timeout;

	drain = 0;
@@ -539,20 +577,24 @@ int offline_pages(unsigned long start_pfn, 
	/* reset pagetype flags */

	start_isolate_page_range(start_pfn, end_pfn);

	/* removal success */

	zone = page_zone(pfn_to_page(start_pfn));

	zone->present_pages -= offlined_pages;

	zone->zone_pgdat->node_present_pages -= offlined_pages;

	totalram_pages -= offlined_pages;

	num_physpages -= offlined_pages;



	vm_total_pages = nr_free_pagecache_pages();

	writeback_set_ratelimit();



	memory_notify(MEM_OFFLINE, &arg);

	return 0;



failed_removal:

	printk(KERN_INFO "memory offlining %lx to %lx failed\n",

		start_pfn, end_pfn);

	memory_notify(MEM_CANCEL_OFFLINE, &arg);

	/* pushback to free area */

	undo_isolate_page_range(start_pfn, end_pfn);



	return ret;

}

#else