memcg: allocate all page_cgroup at boot
Allocate all page_cgroup at boot and remove page_cgroup poitner from
struct page. This patch adds an interface as
struct page_cgroup *lookup_page_cgroup(struct page*)
All FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported.
Remove page_cgroup pointer reduces the amount of memory by
- 4 bytes per PAGE_SIZE.
- 8 bytes per PAGE_SIZE
if memory controller is disabled. (even if configured.)
On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory.
On my x86-64 server with 48GB of memory, this saves 96MB of memory.
I think this reduction makes sense.
By pre-allocation, kmalloc/kfree in charge/uncharge are removed.
This means
- we're not necessary to be afraid of kmalloc faiulre.
(this can happen because of gfp_mask type.)
- we can avoid calling kmalloc/kfree.
- we can avoid allocating tons of small objects which can be fragmented.
- we can know what amount of memory will be used for this extra-lru handling.
I added printk message as
"allocated %ld bytes of page_cgroup"
"please try cgroup_disable=memory option if you don't want"
maybe enough informative for users.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index da2d053..35a7b5e 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -601,8 +601,11 @@
struct zone node_zones[MAX_NR_ZONES];
struct zonelist node_zonelists[MAX_ZONELISTS];
int nr_zones;
-#ifdef CONFIG_FLAT_NODE_MEM_MAP
+#ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
struct page *node_mem_map;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+ struct page_cgroup *node_page_cgroup;
+#endif
#endif
struct bootmem_data *bdata;
#ifdef CONFIG_MEMORY_HOTPLUG
@@ -931,6 +934,7 @@
#endif
struct page;
+struct page_cgroup;
struct mem_section {
/*
* This is, logically, a pointer to an array of struct
@@ -948,6 +952,14 @@
/* See declaration of similar field in struct zone */
unsigned long *pageblock_flags;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+ /*
+ * If !SPARSEMEM, pgdat doesn't have page_cgroup pointer. We use
+ * section. (see memcontrol.h/page_cgroup.h about this.)
+ */
+ struct page_cgroup *page_cgroup;
+ unsigned long pad;
+#endif
};
#ifdef CONFIG_SPARSEMEM_EXTREME