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authorMinchan Kim <minchan@kernel.org>2012-07-31 16:46:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 18:42:50 -0700
commit88fdf75d1bb51d85ba00c466391770056d44bc03 (patch)
tree0b4f6d9b9c0fb39fd03199c6b19ae626608b2fbb
parent93180cec0064d072a984f91c429c5e6bcc816976 (diff)
downloadlinux-88fdf75d1bb51d85ba00c466391770056d44bc03.tar.gz
mm: warn if pg_data_t isn't initialized with zero
Warn if memory-hotplug/boot code doesn't initialize pg_data_t with zero when it is allocated. Arch code and memory hotplug already initiailize pg_data_t. So this warning should never happen. I select fields randomly near the beginning, middle and end of pg_data_t for checking. This patch isn't for performance but for removing initialization code which is necessary to add whenever we adds new field to pg_data_t or zone. Firstly, Andrew suggested clearing out of pg_data_t in MM core part but Tejun doesn't like it because in the future, some archs can initialize some fields in arch code and pass them into general MM part so blindly clearing it out in mm core part would be very annoying. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_alloc.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 48aee0f5902..a6f7576aeca 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4515,6 +4515,9 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
{
pg_data_t *pgdat = NODE_DATA(nid);
+ /* pg_data_t should be reset to zero when it's allocated */
+ WARN_ON(pgdat->nr_zones || pgdat->node_start_pfn || pgdat->classzone_idx);
+
pgdat->node_id = nid;
pgdat->node_start_pfn = node_start_pfn;
calculate_node_totalpages(pgdat, zones_size, zholes_size);