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memcg: fix init_page_cgroup nid with sparsemem 

Commit 21a3c96468 ("memcg: allocate memory cgroup structures in local
nodes") makes page_cgroup allocation as NUMA aware.  But that caused a
problem https://bugzilla.kernel.org/show_bug.cgi?id=36192.

The problem was getting a NID from invalid struct pages, which was not
initialized because it was out-of-node, out of [node_start_pfn,
node_end_pfn)

Now, 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.)

[akpm@linux-foundation.org: try to fix up comments]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki 2011-06-15 15:08:42 -07:00 committed by Linus Torvalds
parent 8957712710
commit 37573e8c71
1 changed files with 53 additions and 18 deletions
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71
mm/page_cgroup.c
View File

@ -162,13 +162,13 @@ 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;
nr = pfn_to_section_nr(pfn);
section = __nr_to_section(nr);
@ -176,7 +176,6 @@ static int __meminit init_section_page_cgroup(unsigned long pfn)
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);
@ -196,7 +195,11 @@ static int __meminit init_section_page_cgroup(unsigned long pfn)
pc = base + index;
init_page_cgroup(pc, nr);
}
/*
* The passed "pfn" may not be aligned to SECTION. For the calculation
* we need to apply a mask.
*/
pfn &= PAGE_SECTION_MASK;
section->page_cgroup = base - pfn;
total_usage += table_size;
return 0;
@ -225,10 +228,20 @@ int __meminit online_page_cgroup(unsigned long start_pfn,
start = start_pfn & ~(PAGES_PER_SECTION - 1);
end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
if (nid == -1) {
/*
* In this case, "nid" already exists and contains valid memory.
* "start_pfn" passed to us is a pfn which is an arg for
* online__pages(), and start_pfn should exist.
*/
nid = pfn_to_nid(start_pfn);
VM_BUG_ON(!node_state(nid, N_ONLINE));
}
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;
@ -284,25 +297,47 @@ static int __meminit page_cgroup_callback(struct notifier_block *self,
void __init page_cgroup_init(void)
{
unsigned long pfn;
int fail = 0;
int nid;
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);
}
if (fail) {
printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
panic("Out of memory");
} else {
hotplug_memory_notifier(page_cgroup_callback, 0);
for_each_node_state(nid, N_HIGH_MEMORY) {
unsigned long start_pfn, end_pfn;
start_pfn = node_start_pfn(nid);
end_pfn = node_end_pfn(nid);
/*
* start_pfn and end_pfn may not be aligned to SECTION and the
* page->flags of out of node pages are not initialized. So we
* scan [start_pfn, the biggest section's pfn < end_pfn) here.
*/
for (pfn = start_pfn;
pfn < end_pfn;
pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
if (!pfn_valid(pfn))
continue;
/*
* Nodes's pfns can be overlapping.
* We know some arch can have a nodes layout such as
* -------------pfn-------------->
* N0 | N1 | N2 | N0 | N1 | N2|....
*/
if (pfn_to_nid(pfn) != nid)
continue;
if (init_section_page_cgroup(pfn, nid))
goto oom;
}
}
hotplug_memory_notifier(page_cgroup_callback, 0);
printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
printk(KERN_INFO "please try 'cgroup_disable=memory' option if you don't"
" want memory cgroups\n");
printk(KERN_INFO "please try 'cgroup_disable=memory' option if you "
"don't want memory cgroups\n");
return;
oom:
printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
panic("Out of memory");
}
void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)