Commit b9ff0360 authored by Oscar Salvador's avatar Oscar Salvador Committed by Linus Torvalds
Browse files

mm/memory_hotplug.c: make add_memory_resource use __try_online_node 

This is a small cleanup for the memhotplug code.  A lot more could be
done, but it is better to start somewhere.  I tried to unify/remove
duplicated code.

The following is what this patchset does:

1) add_memory_resource() has code to allocate a node in case it was
   offline.  Since try_online_node has some code for that as well, I just
   made add_memory_resource() to use that so we can remove duplicated
   code..  This is better explained in patch 1/4.

2) register_mem_sect_under_node() will be called only from
   link_mem_sections()

3) Make register_mem_sect_under_node() a callback of
   walk_memory_range()

4) Drop unnecessary checks from register_mem_sect_under_node()

I have done some tests and I could not see anything broken because of
this patchset.

add_memory_resource() contains code to allocate a new node in case it is
necessary.  Since try_online_node() also has some code for this purpose,
let us make use of that and remove duplicate code.

This introduces __try_online_node(), which is called by
add_memory_resource() and try_online_node().  __try_online_node() has
two new parameters, start_addr of the node, and if the node should be
onlined and registered right away.  This is always wanted if we are
calling from do_cpu_up(), but not when we are calling from memhotplug
code.  Nothing changes from the point of view of the users of
try_online_node(), since try_online_node passes start_addr=0 and
online_node=true to __try_online_node().

Link: http://lkml.kernel.org/r/20180622111839.10071-2-osalvador@techadventures.net


Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarPavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: default avatarReza Arbab <arbab@linux.vnet.ibm.com>
Tested-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 930eaac5

mm/memory_hotplug.c

+39 −28
Original line number Diff line number Diff line
@@ -1034,8 +1034,10 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) 
	return pgdat;

}



static void rollback_node_hotadd(int nid, pg_data_t *pgdat)

static void rollback_node_hotadd(int nid)

{

	pg_data_t *pgdat = NODE_DATA(nid);



	arch_refresh_nodedata(nid, NULL);

	free_percpu(pgdat->per_cpu_nodestats);

	arch_free_nodedata(pgdat);
@@ -1046,28 +1048,48 @@ static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 
/**

 * try_online_node - online a node if offlined

 * @nid: the node ID

 *

 * @start: start addr of the node

 * @set_node_online: Whether we want to online the node

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

 *

 * Returns:

 * 1 -> a new node has been allocated

 * 0 -> the node is already online

 * -ENOMEM -> the node could not be allocated

 */

int try_online_node(int nid)

static int __try_online_node(int nid, u64 start, bool set_node_online)

{

	pg_data_t *pgdat;

	int	ret;

	int ret = 1;



	if (node_online(nid))

		return 0;



	mem_hotplug_begin();

	pgdat = hotadd_new_pgdat(nid, 0);

	pgdat = hotadd_new_pgdat(nid, start);

	if (!pgdat) {

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

		ret = -ENOMEM;

		goto out;

	}



	if (set_node_online) {

		node_set_online(nid);

		ret = register_one_node(nid);

		BUG_ON(ret);

	}

out:

	return ret;

}



/*

 * Users of this function always want to online/register the node

 */

int try_online_node(int nid)

{

	int ret;



	mem_hotplug_begin();

	ret =  __try_online_node(nid, 0, true);

	mem_hotplug_done();

	return ret;

}
@@ -1099,9 +1121,7 @@ static int online_memory_block(struct memory_block *mem, void *arg) 
int __ref add_memory_resource(int nid, struct resource *res, bool online)

{

	u64 start, size;

	pg_data_t *pgdat = NULL;

	bool new_pgdat;

	bool new_node;

	bool new_node = false;

	int ret;



	start = res->start;
@@ -1111,11 +1131,6 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) 
	if (ret)

		return ret;



	{	/* Stupid hack to suppress address-never-null warning */

		void *p = NODE_DATA(nid);

		new_pgdat = !p;

	}



	mem_hotplug_begin();



	/*
@@ -1126,17 +1141,13 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online) 
	 */

	memblock_add_node(start, size, nid);



	new_node = !node_online(nid);

	if (new_node) {

		pgdat = hotadd_new_pgdat(nid, start);

		ret = -ENOMEM;

		if (!pgdat)

	ret = __try_online_node(nid, start, false);

	if (ret < 0)

		goto error;

	}

	new_node = ret;



	/* call arch's memory hotadd */

	ret = arch_add_memory(nid, start, size, NULL, true);



	if (ret < 0)

		goto error;
@@ -1180,8 +1191,8 @@ register_fail: 


error:

	/* rollback pgdat allocation and others */

	if (new_pgdat && pgdat)

		rollback_node_hotadd(nid, pgdat);

	if (new_node)

		rollback_node_hotadd(nid);

	memblock_remove(start, size);



out:

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