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authorYinghai Lu <yinghai@kernel.org>2012-07-11 14:02:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-11 16:04:49 -0700
commit07b4e2bc9c35ea88cbd36d806fcd5e3bcbf022be (patch)
treed9473236dace39c0117cb9107a5d72c07b556d7c
parent688bb4158f64f3af0fe1d13e7642f8c4c402453e (diff)
mm: sparse: fix section usemap placement calculation
Commit 238305bb4d41 ("mm: remove sparsemem allocation details from the bootmem allocator") introduced a bug in the allocation goal calculation that put section usemaps not in the same section as the node descriptors, creating unnecessary hotplug dependencies between them: node 0 must be removed before remove section 16399 node 1 must be removed before remove section 16399 node 2 must be removed before remove section 16399 node 3 must be removed before remove section 16399 node 4 must be removed before remove section 16399 node 5 must be removed before remove section 16399 node 6 must be removed before remove section 16399 The reason is that it applies PAGE_SECTION_MASK to the physical address of the node descriptor when finding a suitable place to put the usemap, when this mask is actually intended to be used with PFNs. Because the PFN mask is wider, the target address will point beyond the wanted section holding the node descriptor and the node must be offlined before the section holding the usemap can go. Fix this by extending the mask to address width before use. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/sparse.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/sparse.c b/mm/sparse.c
index 6a4bf9160e8..e861397016a 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -287,7 +287,7 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
* from the same section as the pgdat where possible to avoid
* this problem.
*/
- goal = __pa(pgdat) & PAGE_SECTION_MASK;
+ goal = __pa(pgdat) & (PAGE_SECTION_MASK << PAGE_SHIFT);
host_pgdat = NODE_DATA(early_pfn_to_nid(goal >> PAGE_SHIFT));
return __alloc_bootmem_node_nopanic(host_pgdat, size,
SMP_CACHE_BYTES, goal);