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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2008-12-01 13:13:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-12-01 19:55:24 -0800
commitdc19f9db38295f811d9041bd89b113beccbd763a (patch)
tree6f1ce3a71df84981b4b5b70fd03f0d1fe20b196e /mm
parentb29acbdcf877009af3f1fc0750bcac314c51e055 (diff)
downloadlinux-2.6.34-ux500-dc19f9db38295f811d9041bd89b113beccbd763a.tar.gz
memcg: memory hotplug fix for notifier callback
Fixes for memcg/memory hotplug. While memory hotplug allocate/free memmap, page_cgroup doesn't free page_cgroup at OFFLINE when page_cgroup is allocated via bootomem. (Because freeing bootmem requires special care.) Then, if page_cgroup is allocated by bootmem and memmap is freed/allocated by memory hotplug, page_cgroup->page == page is no longer true. But current MEM_ONLINE handler doesn't check it and update page_cgroup->page if it's not necessary to allocate page_cgroup. (This was not found because memmap is not freed if SPARSEMEM_VMEMMAP is y.) And I noticed that MEM_ONLINE can be called against "part of section". So, freeing page_cgroup at CANCEL_ONLINE will cause trouble. (freeing used page_cgroup) Don't rollback at CANCEL. One more, current memory hotplug notifier is stopped by slub because it sets NOTIFY_STOP_MASK to return vaule. So, page_cgroup's callback never be called. (low priority than slub now.) I think this slub's behavior is not intentional(BUG). and fixes it. Another way to be considered about page_cgroup allocation: - free page_cgroup at OFFLINE even if it's from bootmem and remove specieal handler. But it requires more changes. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12041 Signed-off-by: KAMEZAWA Hiruyoki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Tested-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_cgroup.c43
-rw-r--r--mm/slub.c6
2 files changed, 33 insertions, 16 deletions
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 436c00229e7..0b3cbf090a6 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -107,19 +107,29 @@ int __init_refok init_section_page_cgroup(unsigned long pfn)
section = __pfn_to_section(pfn);
- if (section->page_cgroup)
- return 0;
-
- nid = page_to_nid(pfn_to_page(pfn));
-
- table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
- 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,
+ if (!section->page_cgroup) {
+ nid = page_to_nid(pfn_to_page(pfn));
+ table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
+ 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));
+ }
+ } else {
+ /*
+ * We don't have to allocate page_cgroup again, but
+ * address of memmap may be changed. So, we have to initialize
+ * again.
+ */
+ base = section->page_cgroup + pfn;
+ table_size = 0;
+ /* check address of memmap is changed or not. */
+ if (base->page == pfn_to_page(pfn))
+ return 0;
}
if (!base) {
@@ -208,18 +218,23 @@ static int __meminit page_cgroup_callback(struct notifier_block *self,
ret = online_page_cgroup(mn->start_pfn,
mn->nr_pages, mn->status_change_nid);
break;
- case MEM_CANCEL_ONLINE:
case MEM_OFFLINE:
offline_page_cgroup(mn->start_pfn,
mn->nr_pages, mn->status_change_nid);
break;
+ case MEM_CANCEL_ONLINE:
case MEM_GOING_OFFLINE:
break;
case MEM_ONLINE:
case MEM_CANCEL_OFFLINE:
break;
}
- ret = notifier_from_errno(ret);
+
+ if (ret)
+ ret = notifier_from_errno(ret);
+ else
+ ret = NOTIFY_OK;
+
return ret;
}
diff --git a/mm/slub.c b/mm/slub.c
index 7ad489af956..749588a50a5 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2931,8 +2931,10 @@ static int slab_memory_callback(struct notifier_block *self,
case MEM_CANCEL_OFFLINE:
break;
}
-
- ret = notifier_from_errno(ret);
+ if (ret)
+ ret = notifier_from_errno(ret);
+ else
+ ret = NOTIFY_OK;
return ret;
}