Commit ebd15302 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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[PATCH] memory hotadd fixes: enhance collision check 



This patch is for collision check enhancement for memory hot add.

It's better to do resouce collision check before doing memory hot add,
which will touch memory management structures.

And add_section() should check section exists or not before calling
sparse_add_one_section(). (sparse_add_one_section() will do another
check anyway. but checking in memory_hotplug.c will be easy to understand.)

Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: keith mannthey <kmannth@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 5d2870fa

mm/memory_hotplug.c

+22 −7
Original line number Diff line number Diff line
@@ -52,6 +52,9 @@ static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 
	int nr_pages = PAGES_PER_SECTION;

	int ret;



	if (pfn_valid(phys_start_pfn))

		return -EEXIST;



	ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);



	if (ret < 0)
@@ -220,10 +223,9 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 
}



/* add this memory to iomem resource */

static int register_memory_resource(u64 start, u64 size)

static struct resource *register_memory_resource(u64 start, u64 size)

{

	struct resource *res;

	int ret = 0;

	res = kzalloc(sizeof(struct resource), GFP_KERNEL);

	BUG_ON(!res);
@@ -235,9 +237,18 @@ static int register_memory_resource(u64 start, u64 size) 
		printk("System RAM resource %llx - %llx cannot be added\n",

		(unsigned long long)res->start, (unsigned long long)res->end);

		kfree(res);

		ret = -EEXIST;

		res = NULL;

	}

	return ret;

	return res;

}



static void release_memory_resource(struct resource *res)

{

	if (!res)

		return;

	release_resource(res);

	kfree(res);

	return;

}
@@ -246,8 +257,13 @@ int add_memory(int nid, u64 start, u64 size) 
{

	pg_data_t *pgdat = NULL;

	int new_pgdat = 0;

	struct resource *res;

	int ret;



	res = register_memory_resource(start, size);

	if (!res)

		return -EEXIST;



	if (!node_online(nid)) {

		pgdat = hotadd_new_pgdat(nid, start);

		if (!pgdat)
@@ -277,14 +293,13 @@ int add_memory(int nid, u64 start, u64 size) 
		BUG_ON(ret);

	}



	/* register this memory as resource */

	ret = register_memory_resource(start, size);



	return ret;

error:

	/* rollback pgdat allocation and others */

	if (new_pgdat)

		rollback_node_hotadd(nid, pgdat);

	if (res)

		release_memory_resource(res);



	return ret;

}

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