The patch titled
Subject: mm: warn if pg_data_t isn't initialized with zero
has been added to the -mm tree. Its filename is
mm-warn-if-pg_data_t-isnt-initialized-with-zero.patch
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From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN mm/page_alloc.c~mm-warn-if-pg_data_t-isnt-initialized-with-zero mm/page_alloc.c
--- a/mm/page_alloc.c~mm-warn-if-pg_data_t-isnt-initialized-with-zero
+++ a/mm/page_alloc.c
@@ -4514,6 +4514,9 @@ void __paginginit free_area_init_node(in
{
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);
_
Subject: Subject: mm: warn if pg_data_t isn't initialized with zero
Patches currently in -mm which might be from minchan@xxxxxxxxxx are
linux-next.patch
swap-allow-swap-readahead-to-be-merged.patch
documentation-update-how-page-cluster-affects-swap-i-o.patch
mm-compaction-cleanup-on-compaction_deferred.patch
mm-clear-pages_scanned-only-if-draining-a-pcp-adds-pages-to-the-buddy-allocator-again.patch
mm-do-not-use-page_count-without-a-page-pin.patch
mm-clean-up-__count_immobile_pages.patch
mm-have-order-0-compaction-start-off-where-it-left-v3.patch
vmscan-remove-obsolete-shrink_control-comment.patch
mm-hotplug-correctly-setup-fallback-zonelists-when-creating-new-pgdat.patch
mm-hotplug-correctly-add-new-zone-to-all-other-nodes-zone-lists.patch
mm-hotplug-free-zone-pageset-when-a-zone-becomes-empty.patch
mm-hotplug-mark-memory-hotplug-code-in-page_allocc-as-__meminit.patch
mm-factor-out-memory-isolate-functions.patch
mm-bug-fix-free-page-check-in-zone_watermark_ok.patch
memory-hotplug-fix-kswapd-looping-forever-problem.patch
memory-hotplug-fix-kswapd-looping-forever-problem-fix.patch
memory-hotplug-fix-kswapd-looping-forever-problem-fix-fix.patch
memcg-prevent-oom-with-too-many-dirty-pages.patch
memcg-further-prevent-oom-with-too-many-dirty-pages.patch
mips-zero-out-pg_data_t-when-its-allocated.patch
mm-warn-if-pg_data_t-isnt-initialized-with-zero.patch
mm-remove-redundant-initialization.patch
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