memcg: fix page_cgroup allocation

page_cgroup_init() is called from mem_cgroup_init(). But at this
point, we cannot call alloc_bootmem().
(and this caused panic at boot.)

This patch moves page_cgroup_init() to init/main.c.

Time table is following:
==
  parse_args(). # we can trust mem_cgroup_subsys.disabled bit after this.
  ....
  cgroup_init_early()  # "early" init of cgroup.
  ....
  setup_arch()         # memmap is allocated.
  ...
  page_cgroup_init();
  mem_init();   # we cannot call alloc_bootmem after this.
  ....
  cgroup_init() # mem_cgroup is initialized.
==

Before page_cgroup_init(), mem_map must be initialized. So,
I added page_cgroup_init() to init/main.c directly.

(*) maybe this is not very clean but
    - cgroup_init_early() is too early
    - in cgroup_init(), we have to use vmalloc instead of alloc_bootmem().
    use of vmalloc area in x86-32 is important and we should avoid very large
    vmalloc() in x86-32. So, we want to use alloc_bootmem() and added page_cgroup_init()
    directly to init/main.c

[akpm@linux-foundation.org: remove unneeded/bad mem_cgroup_subsys declaration]
[akpm@linux-foundation.org: fix build]
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com>
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>

2 files changed, 25 insertions, 8 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d4a92b63e98e..866dcc7eeb0c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1088,7 +1088,6 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
         int node;
 
         if (unlikely((cont->parent) == NULL)) {
-                page_cgroup_init();
                 mem = &init_mem_cgroup;
         } else {
                 mem = mem_cgroup_alloc();
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 78242b4d7edf..f59d797dc5a9 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -4,8 +4,10 @@
 #include <linux/bit_spinlock.h>
 #include <linux/page_cgroup.h>
 #include <linux/hash.h>
+#include <linux/slab.h>
 #include <linux/memory.h>
 #include <linux/vmalloc.h>
+#include <linux/cgroup.h>
 
 static void __meminit
 __init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
@@ -67,6 +69,9 @@ void __init page_cgroup_init(void)
 
         int nid, fail;
 
+        if (mem_cgroup_subsys.disabled)
+                return;
+
         for_each_online_node(nid)  {
                 fail = alloc_node_page_cgroup(nid);
                 if (fail)
@@ -107,9 +112,14 @@ int __meminit init_section_page_cgroup(unsigned long pfn)
         nid = page_to_nid(pfn_to_page(pfn));
 
         table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
-        base = kmalloc_node(table_size, GFP_KERNEL, nid);
-        if (!base)
-                base = vmalloc_node(table_size, nid);
+        if (slab_is_available()) {
+                base = kmalloc_node(table_size, GFP_KERNEL, nid);
+                if (!base)
+                        base = vmalloc_node(table_size, nid);
+        } else {
+                base = __alloc_bootmem_node_nopanic(NODE_DATA(nid), table_size,
+                                PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
+        }
 
         if (!base) {
                 printk(KERN_ERR "page cgroup allocation failure\n");
@@ -136,11 +146,16 @@ void __free_page_cgroup(unsigned long pfn)
         if (!ms || !ms->page_cgroup)
                 return;
         base = ms->page_cgroup + pfn;
-        ms->page_cgroup = NULL;
-        if (is_vmalloc_addr(base))
+        if (is_vmalloc_addr(base)) {
                 vfree(base);
-        else
-                kfree(base);
+                ms->page_cgroup = NULL;
+        } else {
+                struct page *page = virt_to_page(base);
+                if (!PageReserved(page)) { /* Is bootmem ? */
+                        kfree(base);
+                        ms->page_cgroup = NULL;
+                }
+        }
 }
 
 int online_page_cgroup(unsigned long start_pfn,
@@ -214,6 +229,9 @@ void __init page_cgroup_init(void)
         unsigned long pfn;
         int fail = 0;
 
+        if (mem_cgroup_subsys.disabled)
+                return;
+
         for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) {
                 if (!pfn_present(pfn))
                         continue;