The patch titled
Subject: memory hotplug: fix section info double registration bug
has been removed from the -mm tree. Its filename was
memory-hotplug-fix-a-double-register-section-info-bug.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: qiuxishi <[email protected]>
Subject: memory hotplug: fix section info double registration bug
There may be a bug when registering section info. For example, on my
Itanium platform, the pfn range of node0 includes the other nodes, so
other nodes' section info will be double registered, and memmap's page
count will equal to 3.
node0: start_pfn=0x100, spanned_pfn=0x20fb00, present_pfn=0x7f8a3, =>
0x000100-0x20fc00
node1: start_pfn=0x80000, spanned_pfn=0x80000, present_pfn=0x80000, =>
0x080000-0x100000
node2: start_pfn=0x100000, spanned_pfn=0x80000, present_pfn=0x80000, =>
0x100000-0x180000
node3: start_pfn=0x180000, spanned_pfn=0x80000, present_pfn=0x80000, =>
0x180000-0x200000
free_all_bootmem_node()
register_page_bootmem_info_node()
register_page_bootmem_info_section()
When hot remove memory, we can't free the memmap's page because
page_count() is 2 after put_page_bootmem().
sparse_remove_one_section()
free_section_usemap()
free_map_bootmem()
put_page_bootmem()
[[email protected]: add code comment]
Signed-off-by: Xishi Qiu <[email protected]>
Signed-off-by: Jiang Liu <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
mm/memory_hotplug.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff -puN
mm/memory_hotplug.c~memory-hotplug-fix-a-double-register-section-info-bug
mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~memory-hotplug-fix-a-double-register-section-info-bug
+++ a/mm/memory_hotplug.c
@@ -126,9 +126,6 @@ static void register_page_bootmem_info_s
struct mem_section *ms;
struct page *page, *memmap;
- if (!pfn_valid(start_pfn))
- return;
-
section_nr = pfn_to_section_nr(start_pfn);
ms = __nr_to_section(section_nr);
@@ -187,9 +184,16 @@ void register_page_bootmem_info_node(str
end_pfn = pfn + pgdat->node_spanned_pages;
/* register_section info */
- for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
- register_page_bootmem_info_section(pfn);
-
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ /*
+ * Some platforms can assign the same pfn to multiple nodes - on
+ * node0 as well as nodeN. To avoid registering a pfn against
+ * multiple nodes we check that this pfn does not already
+ * reside in some other node.
+ */
+ if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
+ register_page_bootmem_info_section(pfn);
+ }
}
#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
_
Patches currently in -mm which might be from [email protected] are
origin.patch
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