Memoryless nodes: Update memory policy and page migration (56bbd65d) · Commits · 戴 / test

Online nodes now may have no memory. The checks and initialization must therefore be changed to no longer use the online functions. This will correctly initialize the interleave on bootup to only target nodes with memory and will make sys_move_pages return an error when a page is to be moved to a memoryless node. Similarly we will get an error if MPOL_BIND and MPOL_INTERLEAVE is used on a memoryless node. These are somewhat new semantics. So far one could specify memoryless nodes and we would maybe do the right thing and just ignore the node (or we'd do something strange like with MPOL_INTERLEAVE). If we want to allow the specification of memoryless nodes via memory policies then we need to keep checking for online nodes. Signed-off-by:

Christoph Lameter <clameter@sgi.com> Acked-by:

Nishanth Aravamudan <nacc@us.ibm.com> Tested-by:

Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by:

Bob Picco <bob.picco@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@skynet.ie> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/mempolicy.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -494,9 +494,9 @@ static void get_zonemask(struct mempolicy p, nodemask_t nodes)
		*nodes = p->v.nodes;
		break;
		case MPOL_PREFERRED:
		/* or use current node instead of online map? */
		/* or use current node instead of memory_map? */
		if (p->v.preferred_node < 0)
		*nodes = node_online_map;
		*nodes = node_states[N_HIGH_MEMORY];
		else
		node_set(p->v.preferred_node, *nodes);
		break;
		@@ -1687,7 +1687,7 @@ void __init numa_policy_init(void)
		* fall back to the largest node if they're all smaller.
		*/
		nodes_clear(interleave_nodes);
		for_each_online_node(nid) {
		for_each_node_state(nid, N_HIGH_MEMORY) {
		unsigned long total_pages = node_present_pages(nid);

		/* Preserve the largest node */
		@@ -1973,7 +1973,7 @@ int show_numa_map(struct seq_file m, void v)
		seq_printf(m, " huge");
		} else {
		check_pgd_range(vma, vma->vm_start, vma->vm_end,
		&node_online_map, MPOL_MF_STATS, md);
		&node_states[N_HIGH_MEMORY], MPOL_MF_STATS, md);
		}

		if (!md->pages)
		@@ -2000,7 +2000,7 @@ int show_numa_map(struct seq_file m, void v)
		if (md->writeback)
		seq_printf(m," writeback=%lu", md->writeback);

		for_each_online_node(n)
		for_each_node_state(n, N_HIGH_MEMORY)
		if (md->node[n])
		seq_printf(m, " N%d=%lu", n, md->node[n]);
		out:

mm/migrate.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -986,7 +986,7 @@ asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
		goto out;

		err = -ENODEV;
		if (!node_online(node))
		if (!node_state(node, N_HIGH_MEMORY))
		goto out;

		err = -EACCES;

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