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Commit 7049027c authored by Yasunori Goto's avatar Yasunori Goto Committed by Linus Torvalds
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[PATCH] pgdat allocation and update for ia64 of memory hotplug: update pgdat address array 



This is to refresh node_data[] array for ia64.  As I mentioned previous
patches, ia64 has copies of information of pgdat address array on each node as
per node data.

At v2 of node_add, this function used stop_machine_run() to update them.  (I
wished that they were copied safety as much as possible.) But, in this patch,
this arrays are just copied simply, and set node_online_map bit after
completion of pgdat initialization.

So, kernel must touch NODE_DATA() macro after checking node_online_map().
(Current code has already done it.) This is more simple way for just
hot-add.....

Note : It will be problem when hot-remove will occur,
       because, even if online_map bit is set, kernel may
       touch NODE_DATA() due to race condition. :-(

Signed-off-by: default avatarYasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ae5a2c1c

arch/ia64/mm/discontig.c

+19 −5
Original line number Diff line number Diff line
@@ -308,6 +308,17 @@ static void __init reserve_pernode_space(void) 
	}

}



static void __meminit scatter_node_data(void)

{

	pg_data_t **dst;

	int node;



	for_each_online_node(node) {

		dst = LOCAL_DATA_ADDR(pgdat_list[node])->pg_data_ptrs;

		memcpy(dst, pgdat_list, sizeof(pgdat_list));

	}

}



/**

 * initialize_pernode_data - fixup per-cpu & per-node pointers

 *
@@ -320,11 +331,8 @@ static void __init initialize_pernode_data(void) 
{

	int cpu, node;



	/* Copy the pg_data_t list to each node and init the node field */

	for_each_online_node(node) {

		memcpy(mem_data[node].node_data->pg_data_ptrs, pgdat_list,

		       sizeof(pgdat_list));

	}

	scatter_node_data();



#ifdef CONFIG_SMP

	/* Set the node_data pointer for each per-cpu struct */

	for (cpu = 0; cpu < NR_CPUS; cpu++) {
@@ -783,3 +791,9 @@ void __init paging_init(void) 


	zero_page_memmap_ptr = virt_to_page(ia64_imva(empty_zero_page));

}



void arch_refresh_nodedata(int update_node, pg_data_t *update_pgdat)

{

	pgdat_list[update_node] = update_pgdat;

	scatter_node_data();

}

include/asm-ia64/nodedata.h

+12 −0
Original line number Diff line number Diff line
@@ -46,6 +46,18 @@ struct ia64_node_data { 
 */

#define NODE_DATA(nid)		(local_node_data->pg_data_ptrs[nid])



/*

 * LOCAL_DATA_ADDR - This is to calculate the address of other node's

 *		     "local_node_data" at hot-plug phase. The local_node_data

 *		     is pointed by per_cpu_page. Kernel usually use it for

 *		     just executing cpu. However, when new node is hot-added,

 *		     the addresses of local data for other nodes are necessary

 *		     to update all of them.

 */

#define LOCAL_DATA_ADDR(pgdat)  			\

	((struct ia64_node_data *)((u64)(pgdat) + 	\

				   L1_CACHE_ALIGN(sizeof(struct pglist_data))))



#endif /* CONFIG_NUMA */



#endif /* _ASM_IA64_NODEDATA_H */

include/linux/memory_hotplug.h

+1 −3
Original line number Diff line number Diff line
@@ -91,9 +91,7 @@ static inline pg_data_t *arch_alloc_nodedata(int nid) 
static inline void arch_free_nodedata(pg_data_t *pgdat)

{

}

static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat)

{

}

extern void arch_refresh_nodedata(int nid, pg_data_t *pgdat);



#else /* CONFIG_HAVE_ARCH_NODEDATA_EXTENSION */