[patch -mm] mm: slab allocate memory section nodemask for large systems

David Rientjes
2009-11-18T00:19:33Z

Nodemasks should not be allocated on the stack for large systems (when it
is larger than 256 bytes) since there is a threat of overflow.

This patch causes the unregister_mem_sect_under_nodes() nodemask to be
allocated on the stack for smaller systems and be allocated by slab for
larger systems.

GFP_KERNEL is used since remove_memory_block() can block.

Cc: Gary Hade <garyhade@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Alex Chiang <achiang@hp.com>
Signed-off-by: David Rientjes <rientjes@google.com>
---
drivers/base/node.c | 13 +++++++++----
1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -363,12 +363,16 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
/* unregister memory section under all nodes that it spans */
int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
{
- nodemask_t unlinked_nodes;
+ NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
unsigned long pfn, sect_start_pfn, sect_end_pfn;

- if (!mem_blk)
+ if (!mem_blk) {
+ NODEMASK_FREE(unlinked_nodes);
return -EFAULT;
- nodes_clear(unlinked_nodes);
+ }
+ if (!unlinked_nodes)
+ return -ENOMEM;
+ nodes_clear(*unlinked_nodes);
sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
@@ -379,13 +383,14 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
continue;
if (!node_online(nid))
continue;
- if (node_test_and_set(nid, unlinked_nodes))
+ if (node_test_and_set(nid, *unlinked_nodes))
continue;
sysfs_remove_link(&node_devices[nid].sysdev.kobj,
kobject_name(&mem_blk->sysdev.kobj));
sysfs_remove_link(&mem_blk->sysdev.kobj,
kobject_name(&node_devices[nid].sysdev.kobj));
}
+ NODEMASK_FREE(unlinked_nodes);
return 0;
}