On Wed, 8 Jun 2011 08:40:34 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> On Tue, 7 Jun 2011 11:18:57 +0100
> Mel Gorman <mgorman@xxxxxxx> wrote:
> > I also don't think the ARM punching holes in the memmap is a problem
> > because we'd at least expect the start of the node to be valid.
> >
>
> Ok, I'll post a fixed and cleaned one. (above patch has bug ;(
>
> Thanks,
> -Kame
>
fixed one here. I found another bug in node hotplug and will post
a fix later.
==
With sparsemem, page_cgroup_init scans pfn from 0 to max_pfn.
But this may scan a pfn which is not on any node and can access
memmap which is not initialized.
This makes page_cgroup_init() for SPARSEMEM node aware and remove
a code to get nid from page->flags. (Then, we'll use valid NID
always.)
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
mm/page_cgroup.c | 41 +++++++++++++++++++++++++++++++++--------
1 file changed, 33 insertions(+), 8 deletions(-)
Index: linux-3.0-rc1/mm/page_cgroup.c
===================================================================
--- linux-3.0-rc1.orig/mm/page_cgroup.c
+++ linux-3.0-rc1/mm/page_cgroup.c
@@ -162,21 +162,25 @@ static void free_page_cgroup(void *addr)
}
#endif
-static int __meminit init_section_page_cgroup(unsigned long pfn)
+static int __meminit init_section_page_cgroup(unsigned long pfn, int nid)
{
struct page_cgroup *base, *pc;
struct mem_section *section;
unsigned long table_size;
unsigned long nr;
- int nid, index;
+ int index;
+ /*
+ * Even if passed 'pfn' is not aligned to section, we need to align
+ * it to section boundary because of SPARSEMEM pfn calculation.
+ */
+ pfn = ALIGN(pfn, PAGES_PER_SECTION);
nr = pfn_to_section_nr(pfn);
section = __nr_to_section(nr);
if (section->page_cgroup)
return 0;
- nid = page_to_nid(pfn_to_page(pfn));
table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
base = alloc_page_cgroup(table_size, nid);
@@ -228,7 +232,7 @@ int __meminit online_page_cgroup(unsigne
for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
if (!pfn_present(pfn))
continue;
- fail = init_section_page_cgroup(pfn);
+ fail = init_section_page_cgroup(pfn, nid);
}
if (!fail)
return 0;
@@ -285,14 +289,35 @@ void __init page_cgroup_init(void)
{
unsigned long pfn;
int fail = 0;
+ int node;
if (mem_cgroup_disabled())
return;
- for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) {
- if (!pfn_present(pfn))
- continue;
- fail = init_section_page_cgroup(pfn);
+ for_each_node_state(node, N_HIGH_MEMORY) {
+ unsigned long start_pfn, end_pfn;
+
+ start_pfn = NODE_DATA(node)->node_start_pfn;
+ end_pfn = start_pfn + NODE_DATA(node)->node_spanned_pages;
+ /*
+ * Because we cannot trust page->flags of page out of node
+ * boundary, we skip pfn < start_pfn.
+ */
+ for (pfn = start_pfn;
+ !fail && (pfn < end_pfn);
+ pfn = ALIGN(pfn + PAGES_PER_SECTION, PAGES_PER_SECTION)) {
+ if (!pfn_present(pfn))
+ continue;
+ /*
+ * Nodes can be overlapped
+ * We know some arch can have nodes layout as
+ * -------------pfn-------------->
+ * N0 | N1 | N2 | N0 | N1 | N2 |.....
+ */
+ if (pfn_to_nid(pfn) != node)
+ continue;
+ fail = init_section_page_cgroup(pfn, node);
+ }
}
if (fail) {
printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
--
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