Re: [PATCH 9/13] memcg: lookup page cgroup (and remove pointer from struct page)

KAMEZAWA Hiroyuki
2008-09-24T03:09:40Z

On Wed, 24 Sep 2008 07:39:58 +0530
"Balbir Singh" <balbir@linux.vnet.ibm.com> wrote:
> > I'll add FLATMEM/DISCONTIGMEM/SPARSEMEM support directly.
> > I already have wasted a month on this not-interesting work and want to fix
> > this soon.
> >
>
> Let's look at the basic requirement, make memory resource controller
> not suck with 32 bit systems. I have been thinking of about removing
> page_cgroup from struct page only for 32 bit systems (use radix tree),
> 32 bit systems can have a maximum of 64GB if PAE is enabled, I suspect
> radix tree should work there and let the 64 bit systems work as is. If
> performance is an issue, I would recommend the 32 bit folks upgrade to
> 64 bit :) Can we build consensus around this approach?
>
My thinking is below. (assume 64bit)

- remove page_cgroup pointer from struct page allows us to reduce
static memory usage at boot by 8bytes/4096bytes if memory cgroup is disabled.
This reaches 96MB on my 48 GB box. I think this is big.
- pre-allocation of page_cgroup gives us following.
Pros.
- We are not necessary to be afraid of "failure of kmalloc" and
"goes down to memory reclaim at kmalloc"
This makes memory resource controller much simpler and robust.
- We can know what amount of kernel memory will be used for
LRU pages management.
Cons.
- All page_cgroups are allocated at boot.
This reaches 480MB on my 48GB box.

But I think we can ignore "Cons.". If we use up memory, we'll use tons of
page_cgroup. Considering memory fragmentation caused by allocating a lots of
very small object, pre-allocation makes memcg better.

> > I'm glad if people help me to test FLATMEM/DISCONTIGMEM/SPARSEMEM because
> > there are various kinds of memory map. I have only x86-64 box.
>
> I can help test your patches on powerpc 64 bit and find a 32 bit
> system to test it as well. What do you think about the points above?
>
In Kconfig, x86-64 just uses SPARSEMEM and FLATMEM/DISCONTIGMEM cannot be selected.
I can compile by hand but cannot do real test.

I already wrote a replacement, quite easy to read.
(now under test.)

==
pre-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.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

include/linux/memcontrol.h | 11 -
include/linux/mm_types.h | 4
include/linux/mmzone.h | 8 +
include/linux/page_cgroup.h | 90 +++++++++++++++
mm/Makefile | 2
mm/memcontrol.c | 256 ++++++++++++--------------------------------
mm/page_alloc.c | 10 -
mm/page_cgroup.c | 200 ++++++++++++++++++++++++++++++++++
8 files changed, 374 insertions(+), 207 deletions(-)

Index: mmotm-2.6.27-rc6+/mm/page_cgroup.c
===================================================================
--- /dev/null
+++ mmotm-2.6.27-rc6+/mm/page_cgroup.c
@@ -0,0 +1,243 @@
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/bootmem.h>
+#include <linux/bit_spinlock.h>
+#include <linux/page_cgroup.h>
+#include <linux/hash.h>
+#include <linux/memory.h>
+
+static void __meminit
+__init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
+{
+ pc->flags = 0;
+ pc->mem_cgroup = NULL;
+ pc->page = pfn_to_page(pfn);
+}
+
+#ifdef CONFIG_FLAT_NODE_MEM_MAP
+
+static unsigned long total_usage = 0;
+
+void __init pgdat_page_cgroup_init(struct pglist_data *pgdat)
+{
+ pgdat->node_page_cgroup = NULL;
+}
+
+struct page_cgroup *lookup_page_cgroup(struct page *page)
+{
+ unsigned long pfn = page_to_pfn(page);
+ unsigned long offset;
+ struct page_cgroup *base;
+
+ base = NODE_DATA(page_to_nid(nid))->node_page_cgroup;
+ if (unlikely(!base))
+ return NULL;
+
+ offset = pfn - NODE_DATA(page_to_nid(page))->node_start_pfn;
+ return base + offset;
+}
+
+static int __init alloc_node_page_cgroup(int nid)
+{
+ struct page_cgroup *base, *pc;
+ unsigned long table_size;
+ unsigned long start_pfn, nr_pages, index;
+
+ start_pfn = NODE_DATA(nid)->node_start_pfn;
+ nr_pages = NODE_DATA(nid)->node_spanned_pages;
+
+ table_size = sizeof(struct page_cgroup) * nr_pages;
+
+ base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
+ table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
+ if (!base)
+ return -ENOMEM;
+ for (index = 0; index < nr_pages; index++) {
+ pc = base + index;
+ __init_page_cgroup(pc, start_pfn + index);
+ }
+ NODE_DATA(nid)->node_page_cgroup = base;
+ total_usage += table_size;
+ return 0;
+}
+
+void __init free_node_page_cgroup(int nid)
+{
+ unsigned long table_size;
+ unsigned long nr_pages;
+ struct page_cgroup *base;
+
+ base = NODE_DATA(nid)->node_page_cgroup;
+ if (!base)
+ return;
+ nr_pages = NODE_DATA(nid)->node_spanned_pages;
+
+ table_size = sizeof(struct page_cgroup) * nr_pages;
+
+ free_bootmem_node(NODE_DATA(nid),
+ (unsigned long)base, table_size);
+ NODE_DATA(nid)->node_page_cgroup = NULL;
+}
+
+void __init page_cgroup_init(void)
+{
+
+ int nid, fail;
+
+ for_each_online_node(nid) {
+ fail = alloc_node_page_cgroup(nid);
+ if (fail)
+ goto fail;
+ }
+ printk("allocate page_cgroup at boot for %ld bytes", total_usage);
+ printk("please try cgroup_disable=memory option if you don't want\n");
+ return;
+fail:
+ printk("allocation of page_cgroup was failed.\n");
+ printk("please try cgroup_disable=memory boot option\n");
+ panic("Out of memory");
+}
+
+#else /* CONFIG_FLAT_NODE_MEM_MAP */
+
+struct page_cgroup *lookup_page_cgroup(struct page *page)
+{
+ unsigned long pfn = page_to_pfn(page);
+ struct mem_section *section = __pfn_to_section(pfn);
+
+ return section->page_cgroup + pfn;
+}
+
+int __meminit init_section_page_cgroup(unsigned long pfn)
+{
+ struct mem_section *section;
+ struct page_cgroup *base, *pc;
+ unsigned long total_size;
+ int nid, index;
+
+ section = __pfn_to_section(pfn);
+
+ if (section->page_cgroup)
+ return 0;
+
+ nid = page_to_nid(pfn_to_page(pfn));
+
+ total_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
+ base = vmalloc_node(total_size, nid);
+ if (!base) {
+ printk("page cgroup allocation failure\n");
+ return -ENOMEM;
+ }
+ for (index = 0; index < PAGES_PER_SECTION; index++) {
+ pc = base + index;
+ __init_page_cgroup(pc, pfn + index);
+ }
+
+ section = __pfn_to_section(pfn);
+ section->page_cgroup = base - pfn;
+ return 0;
+}
+#ifdef CONFIG_MEMORY_HOTPLUG
+void __free_page_cgroup(unsigned long pfn)
+{
+ struct mem_section *ms;
+ struct page_cgroup *base;
+
+ ms = __pfn_to_section(pfn);
+ if (!ms || !ms->page_cgroup)
+ return;
+ base = ms->page_cgroup + pfn;
+ ms->page_cgroup = NULL;
+ vfree(base);
+}
+
+int online_page_cgroup(unsigned long start_pfn,
+ unsigned long nr_pages,
+ int nid)
+{
+ unsigned long start, end, pfn;
+ int fail = 0;
+
+ start = start_pfn & (PAGES_PER_SECTION - 1);
+ end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
+
+ for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
+ if (!pfn_present(pfn))
+ continue;
+ fail = init_section_page_cgroup(pfn);
+ }
+ if (!fail)
+ return 0;
+
+ /* rollback */
+ for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
+ __free_page_cgroup(pfn);
+
+ return -ENOMEM;
+}
+
+int offline_page_cgroup(unsigned long start_pfn,
+ unsigned long nr_pages, int nid)
+{
+ unsigned long start, end, pfn;
+
+ start = start_pfn & (PAGES_PER_SECTION - 1);
+ end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
+
+ for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
+ __free_page_cgroup(pfn);
+ return 0;
+
+}
+
+static int page_cgroup_callback(struct notifier_block *self,
+ unsigned long action, void *arg)
+{
+ struct memory_notify *mn = arg;
+ int ret = 0;
+ switch (action) {
+ case MEM_GOING_ONLINE:
+ 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_GOING_OFFLINE:
+ break;
+ case MEM_ONLINE:
+ case MEM_CANCEL_OFFLINE:
+ break;
+ }
+ ret = notifier_from_errno(ret);
+ return ret;
+}
+
+#endif
+
+void __init page_cgroup_init(void)
+{
+ unsigned long pfn;
+ int fail = 0;
+
+ 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("please try cgroup_disable=memory boot option\n");
+ panic("Out of memory");
+ } else {
+ hotplug_memory_notifier(page_cgroup_callback, 0);
+ }
+}
+
+void __init pgdat_page_cgroup_init(struct pgdata_list *pgdat)
+{
+ return;
+}
+
+#endif
Index: mmotm-2.6.27-rc6+/include/linux/mm_types.h
===================================================================
--- mmotm-2.6.27-rc6+.orig/include/linux/mm_types.h
+++ mmotm-2.6.27-rc6+/include/linux/mm_types.h
@@ -94,10 +94,6 @@ struct page {
void *virtual; /* Kernel virtual address (NULL if
not kmapped, ie. highmem) */
#endif /* WANT_PAGE_VIRTUAL */
-#ifdef CONFIG_CGROUP_MEM_RES_CTLR
- unsigned long page_cgroup;
-#endif
-
#ifdef CONFIG_KMEMCHECK
void *shadow;
#endif
Index: mmotm-2.6.27-rc6+/mm/Makefile
===================================================================
--- mmotm-2.6.27-rc6+.orig/mm/Makefile
+++ mmotm-2.6.27-rc6+/mm/Makefile
@@ -34,6 +34,6 @@ obj-$(CONFIG_FS_XIP) += filemap_xip.o
obj-$(CONFIG_MIGRATION) += migrate.o
obj-$(CONFIG_SMP) += allocpercpu.o
obj-$(CONFIG_QUICKLIST) += quicklist.o
-obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o
+obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
obj-$(CONFIG_CGROUP_MEMRLIMIT_CTLR) += memrlimitcgroup.o
obj-$(CONFIG_KMEMTRACE) += kmemtrace.o
Index: mmotm-2.6.27-rc6+/include/linux/page_cgroup.h
===================================================================
--- /dev/null
+++ mmotm-2.6.27-rc6+/include/linux/page_cgroup.h
@@ -0,0 +1,90 @@
+#ifndef __LINUX_PAGE_CGROUP_H
+#define __LINUX_PAGE_CGROUP_H
+
+/*
+ * Page Cgroup can be considered as an extended mem_map.
+ * A page_cgroup page is associated with every page descriptor. The
+ * page_cgroup helps us identify information about the cgroup
+ * All page cgroups are allocated at boot or memory hotplug event,
+ * then the page cgroup for pfn always exists.
+ */
+struct page_cgroup {
+ unsigned long flags;
+ struct mem_cgroup *mem_cgroup;
+ struct page *page;
+ struct list_head lru; /* per cgroup LRU list */
+};
+
+void __init pgdat_page_cgroup_init(struct pglist_data *pgdat);
+void __init page_cgroup_init(void);
+struct page_cgroup *lookup_page_cgroup(struct page *page);
+
+enum {
+ /* flags for mem_cgroup */
+ PCG_LOCK, /* page cgroup is locked */
+ PCG_CACHE, /* charged as cache */
+ PCG_USED, /* this object is in use. */
+ /* flags for LRU placement */
+ PCG_ACTIVE, /* page is active in this cgroup */
+ PCG_FILE, /* page is file system backed */
+ PCG_UNEVICTABLE, /* page is unevictableable */
+};
+
+#define TESTPCGFLAG(uname, lname) \
+static inline int PageCgroup##uname(struct page_cgroup *pc) \
+ { return test_bit(PCG_##lname, &pc->flags); }
+
+#define SETPCGFLAG(uname, lname) \
+static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
+ { set_bit(PCG_##lname, &pc->flags); }
+
+#define CLEARPCGFLAG(uname, lname) \
+static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \
+ { clear_bit(PCG_##lname, &pc->flags); }
+
+/* Cache flag is set only once (at allocation) */
+TESTPCGFLAG(Cache, CACHE)
+
+TESTPCGFLAG(Used, USED)
+CLEARPCGFLAG(Used, USED)
+
+/* LRU management flags (from global-lru definition) */
+TESTPCGFLAG(File, FILE)
+SETPCGFLAG(File, FILE)
+CLEARPCGFLAG(File, FILE)
+
+TESTPCGFLAG(Active, ACTIVE)
+SETPCGFLAG(Active, ACTIVE)
+CLEARPCGFLAG(Active, ACTIVE)
+
+TESTPCGFLAG(Unevictable, UNEVICTABLE)
+SETPCGFLAG(Unevictable, UNEVICTABLE)
+CLEARPCGFLAG(Unevictable, UNEVICTABLE)
+
+static inline int page_cgroup_nid(struct page_cgroup *pc)
+{
+ return page_to_nid(pc->page);
+}
+
+static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
+{
+ return page_zonenum(pc->page);
+}
+
+static inline void lock_page_cgroup(struct page_cgroup *pc)
+{
+ bit_spin_lock(PCG_LOCK, &pc->flags);
+}
+
+static inline int trylock_page_cgroup(struct page_cgroup *pc)
+{
+ return bit_spin_trylock(PCG_LOCK, &pc->flags);
+}
+
+static inline void unlock_page_cgroup(struct page_cgroup *pc)
+{
+ bit_spin_unlock(PCG_LOCK, &pc->flags);
+}
+
+
+#endif
Index: mmotm-2.6.27-rc6+/mm/memcontrol.c
===================================================================
--- mmotm-2.6.27-rc6+.orig/mm/memcontrol.c
+++ mmotm-2.6.27-rc6+/mm/memcontrol.c
@@ -34,11 +34,11 @@
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/mm_inline.h>
+#include <linux/page_cgroup.h>

#include <asm/uaccess.h>

struct cgroup_subsys mem_cgroup_subsys __read_mostly;
-static struct kmem_cache *page_cgroup_cache __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES 5

/*
@@ -138,80 +138,6 @@ static struct mem_cgroup init_mem_cgroup

#define is_root_cgroup(cgrp) ((cgrp) == &init_mem_cgroup)

-
-/*
- * We use the lower bit of the page->page_cgroup pointer as a bit spin
- * lock. We need to ensure that page->page_cgroup is at least two
- * byte aligned (based on comments from Nick Piggin). But since
- * bit_spin_lock doesn't actually set that lock bit in a non-debug
- * uniprocessor kernel, we should avoid setting it here too.
- */
-#define PAGE_CGROUP_LOCK_BIT 0x0
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
-#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)
-#else
-#define PAGE_CGROUP_LOCK 0x0
-#endif
-
-/*
- * A page_cgroup page is associated with every page descriptor. The
- * page_cgroup helps us identify information about the cgroup
- */
-struct page_cgroup {
- struct list_head lru; /* per cgroup LRU list */
- struct page *page;
- struct mem_cgroup *mem_cgroup;
- unsigned long flags;
-};
-
-enum {
- /* flags for mem_cgroup */
- PCG_CACHE, /* charged as cache */
- /* flags for LRU placement */
- PCG_ACTIVE, /* page is active in this cgroup */
- PCG_FILE, /* page is file system backed */
- PCG_UNEVICTABLE, /* page is unevictableable */
-};
-
-#define TESTPCGFLAG(uname, lname) \
-static inline int PageCgroup##uname(struct page_cgroup *pc) \
- { return test_bit(PCG_##lname, &pc->flags); }
-
-#define SETPCGFLAG(uname, lname) \
-static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
- { set_bit(PCG_##lname, &pc->flags); }
-
-#define CLEARPCGFLAG(uname, lname) \
-static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \
- { clear_bit(PCG_##lname, &pc->flags); }
-
-
-/* Cache flag is set only once (at allocation) */
-TESTPCGFLAG(Cache, CACHE)
-
-/* LRU management flags (from global-lru definition) */
-TESTPCGFLAG(File, FILE)
-SETPCGFLAG(File, FILE)
-CLEARPCGFLAG(File, FILE)
-
-TESTPCGFLAG(Active, ACTIVE)
-SETPCGFLAG(Active, ACTIVE)
-CLEARPCGFLAG(Active, ACTIVE)
-
-TESTPCGFLAG(Unevictable, UNEVICTABLE)
-SETPCGFLAG(Unevictable, UNEVICTABLE)
-CLEARPCGFLAG(Unevictable, UNEVICTABLE)
-
-static int page_cgroup_nid(struct page_cgroup *pc)
-{
- return page_to_nid(pc->page);
-}
-
-static enum zone_type page_cgroup_zid(struct page_cgroup *pc)
-{
- return page_zonenum(pc->page);
-}
-
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
@@ -222,9 +148,9 @@ enum charge_type {

static const unsigned long
pcg_default_flags[NR_CHARGE_TYPE] = {
- ((1 << PCG_CACHE) | (1 << PCG_FILE)),
- ((1 << PCG_ACTIVE)),
- ((1 << PCG_ACTIVE) | (1 << PCG_CACHE)),
+ (1 << PCG_CACHE) | (1 << PCG_FILE) | (1 << PCG_USED) | (1 << PCG_LOCK),
+ (1 << PCG_ACTIVE) | (1 << PCG_LOCK) | (1 << PCG_USED),
+ (1 << PCG_ACTIVE) | (1 << PCG_CACHE) | (1 << PCG_USED)| (1 << PCG_LOCK),
0,
};

@@ -307,37 +233,6 @@ struct mem_cgroup *mem_cgroup_from_task(
struct mem_cgroup, css);
}

-static inline int page_cgroup_locked(struct page *page)
-{
- return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
-
-static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
-{
- VM_BUG_ON(!page_cgroup_locked(page));
- page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK);
-}
-
-struct page_cgroup *page_get_page_cgroup(struct page *page)
-{
- return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK);
-}
-
-static void lock_page_cgroup(struct page *page)
-{
- bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
-
-static int try_lock_page_cgroup(struct page *page)
-{
- return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
-
-static void unlock_page_cgroup(struct page *page)
-{
- bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
-}
-
static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
@@ -441,22 +336,19 @@ void mem_cgroup_move_lists(struct page *
* safely get to page_cgroup without it, so just try_lock it:
* mem_cgroup_isolate_pages allows for page left on wrong list.
*/
- if (!try_lock_page_cgroup(page))
+ pc = lookup_page_cgroup(page);
+
+ if (!trylock_page_cgroup(pc))
return;

- pc = page_get_page_cgroup(page);
- if (pc) {
+ if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
- /*
- * check against the race with move_account.
- */
- if (likely(mem == pc->mem_cgroup))
- __mem_cgroup_move_lists(pc, lru);
+ __mem_cgroup_move_lists(pc, lru);
spin_unlock_irqrestore(&mz->lru_lock, flags);
}
- unlock_page_cgroup(page);
+ unlock_page_cgroup(pc);
}

/*
@@ -543,6 +435,8 @@ unsigned long mem_cgroup_isolate_pages(u
list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
if (scan >= nr_to_scan)
break;
+ if (unlikely(!PageCgroupUsed(pc)))
+ continue;
page = pc->page;

if (unlikely(!PageLRU(page)))
@@ -611,12 +505,12 @@ int mem_cgroup_move_account(struct page
/* Now, we assume no_limit...no failure here. */
return ret;
}
- if (!try_lock_page_cgroup(page)) {
+ if (!trylock_page_cgroup(pc)) {
res_counter_uncharge(&to->res, PAGE_SIZE);
return ret;
}

- if (page_get_page_cgroup(page) != pc) {
+ if (!PageCgroupUsed(pc)) {
res_counter_uncharge(&to->res, PAGE_SIZE);
goto out;
}
@@ -634,7 +528,7 @@ int mem_cgroup_move_account(struct page
res_counter_uncharge(&to->res, PAGE_SIZE);
}
out:
- unlock_page_cgroup(page);
+ unlock_page_cgroup(pc);

return ret;
}
@@ -651,26 +545,27 @@ static int mem_cgroup_charge_common(stru
{
struct mem_cgroup *mem;
struct page_cgroup *pc;
- unsigned long flags;
unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct mem_cgroup_per_zone *mz;
+ unsigned long flags;

- pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
- if (unlikely(pc == NULL))
- goto err;
-
+ pc = lookup_page_cgroup(page);
+ /* can happen at boot */
+ if (unlikely(!pc))
+ return 0;
+ prefetchw(pc);
/*
* We always charge the cgroup the mm_struct belongs to.
* The mm_struct's mem_cgroup changes on task migration if the
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
+
if (likely(!memcg)) {
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!mem)) {
rcu_read_unlock();
- kmem_cache_free(page_cgroup_cache, pc);
return 0;
}
/*
@@ -706,36 +601,34 @@ static int mem_cgroup_charge_common(stru
}
}

+ preempt_disable();
+ lock_page_cgroup(pc);
+ if (unlikely(PageCgroupUsed(pc))) {
+ unlock_page_cgroup(pc);
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ css_put(&mem->css);
+ preempt_enable();
+ goto done;
+ }
pc->mem_cgroup = mem;
- pc->page = page;
/*
* If a page is accounted as a page cache, insert to inactive list.
* If anon, insert to active list.
*/
pc->flags = pcg_default_flags[ctype];

- lock_page_cgroup(page);
- if (unlikely(page_get_page_cgroup(page))) {
- unlock_page_cgroup(page);
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
- kmem_cache_free(page_cgroup_cache, pc);
- goto done;
- }
- page_assign_page_cgroup(page, pc);
-
mz = page_cgroup_zoneinfo(pc);
+
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_add_list(mz, pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+ unlock_page_cgroup(pc);
+ preempt_enable();

- unlock_page_cgroup(page);
done:
return 0;
out:
css_put(&mem->css);
- kmem_cache_free(page_cgroup_cache, pc);
-err:
return -ENOMEM;
}

@@ -743,7 +636,8 @@ int mem_cgroup_charge(struct page *page,
{
if (mem_cgroup_subsys.disabled)
return 0;
-
+ if (PageCompound(page))
+ return 0;
/*
* If already mapped, we don't have to account.
* If page cache, page->mapping has address_space.
@@ -764,7 +658,8 @@ int mem_cgroup_cache_charge(struct page
{
if (mem_cgroup_subsys.disabled)
return 0;
-
+ if (PageCompound(page))
+ return 0;
/*
* Corner case handling. This is called from add_to_page_cache()
* in usual. But some FS (shmem) precharges this page before calling it
@@ -777,15 +672,16 @@ int mem_cgroup_cache_charge(struct page
if (!(gfp_mask & __GFP_WAIT)) {
struct page_cgroup *pc;

- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (pc) {
- VM_BUG_ON(pc->page != page);
- VM_BUG_ON(!pc->mem_cgroup);
- unlock_page_cgroup(page);
+
+ pc = lookup_page_cgroup(page);
+ if (!pc)
+ return 0;
+ lock_page_cgroup(pc);
+ if (PageCgroupUsed(pc)) {
+ unlock_page_cgroup(pc);
return 0;
}
- unlock_page_cgroup(page);
+ unlock_page_cgroup(pc);
}

if (unlikely(!mm))
@@ -812,49 +708,41 @@ __mem_cgroup_uncharge_common(struct page

if (mem_cgroup_subsys.disabled)
return;
+ /* check the condition we can know from page */

- /*
- * Check if our page_cgroup is valid
- */
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (unlikely(!pc))
- goto unlock;
-
- VM_BUG_ON(pc->page != page);
+ pc = lookup_page_cgroup(page);
+ if (unlikely(!pc || !PageCgroupUsed(pc)))
+ return;
+ preempt_disable();
+ lock_page_cgroup(pc);
+ if (unlikely(page_mapped(page))) {
+ unlock_page_cgroup(pc);
+ preempt_enable();
+ return;
+ }
+ ClearPageCgroupUsed(pc);
+ unlock_page_cgroup(pc);

- if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
- && ((PageCgroupCache(pc) || page_mapped(page))))
- goto unlock;
-retry:
mem = pc->mem_cgroup;
mz = page_cgroup_zoneinfo(pc);
+
spin_lock_irqsave(&mz->lru_lock, flags);
- if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED &&
- unlikely(mem != pc->mem_cgroup)) {
- /* MAPPED account can be done without lock_page().
- Check race with mem_cgroup_move_account() */
- spin_unlock_irqrestore(&mz->lru_lock, flags);
- goto retry;
- }
__mem_cgroup_remove_list(mz, pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
-
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
-
-
- res_counter_uncharge(&mem->res, PAGE_SIZE);
+ pc->mem_cgroup = NULL;
css_put(&mem->css);
+ preempt_enable();
+ res_counter_uncharge(&mem->res, PAGE_SIZE);

- kmem_cache_free(page_cgroup_cache, pc);
return;
-unlock:
- unlock_page_cgroup(page);
}

void mem_cgroup_uncharge_page(struct page *page)
{
+ if (page_mapped(page))
+ return;
+ if (page->mapping && !PageAnon(page))
+ return;
__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
}

@@ -878,9 +766,9 @@ int mem_cgroup_prepare_migration(struct
if (mem_cgroup_subsys.disabled)
return 0;

- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (pc) {
+ pc = lookup_page_cgroup(page);
+ lock_page_cgroup(pc);
+ if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
css_get(&mem->css);
if (PageCgroupCache(pc)) {
@@ -890,7 +778,7 @@ int mem_cgroup_prepare_migration(struct
ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
}
}
- unlock_page_cgroup(page);
+ unlock_page_cgroup(pc);
if (mem) {
ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
ctype, mem);
@@ -1271,8 +1159,8 @@ mem_cgroup_create(struct cgroup_subsys *
int node;

if (unlikely((cont->parent) == NULL)) {
+ page_cgroup_init();
mem = &init_mem_cgroup;
- page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
} else {
mem = mem_cgroup_alloc();
if (!mem)
Index: mmotm-2.6.27-rc6+/mm/page_alloc.c
===================================================================
--- mmotm-2.6.27-rc6+.orig/mm/page_alloc.c
+++ mmotm-2.6.27-rc6+/mm/page_alloc.c
@@ -223,17 +223,12 @@ static inline int bad_range(struct zone

static void bad_page(struct page *page)
{
- void *pc = page_get_page_cgroup(page);
-
printk(KERN_EMERG "Bad page state in process '%s'\n" KERN_EMERG
"page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n",
current->comm, page, (int)(2*sizeof(unsigned long)),
(unsigned long)page->flags, page->mapping,
page_mapcount(page), page_count(page));
- if (pc) {
- printk(KERN_EMERG "cgroup:%p\n", pc);
- page_reset_bad_cgroup(page);
- }
+
printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
KERN_EMERG "Backtrace:\n");
dump_stack();
@@ -472,7 +467,6 @@ static inline void free_pages_check(stru
free_page_mlock(page);
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
- (page_get_page_cgroup(page) != NULL) |
(page_count(page) != 0) |
(page->flags & PAGE_FLAGS_CHECK_AT_FREE)))
bad_page(page);
@@ -609,7 +603,6 @@ static void prep_new_page(struct page *p
{
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
- (page_get_page_cgroup(page) != NULL) |
(page_count(page) != 0) |
(page->flags & PAGE_FLAGS_CHECK_AT_PREP)))
bad_page(page);
@@ -3495,6 +3488,7 @@ static void __paginginit free_area_init_
pgdat->nr_zones = 0;
init_waitqueue_head(&pgdat->kswapd_wait);
pgdat->kswapd_max_order = 0;
+ pgdat_page_cgroup_init(pgdat);

for (j = 0; j < MAX_NR_ZONES; j++) {
struct zone *zone = pgdat->node_zones + j;
Index: mmotm-2.6.27-rc6+/include/linux/mmzone.h
===================================================================
--- mmotm-2.6.27-rc6+.orig/include/linux/mmzone.h
+++ mmotm-2.6.27-rc6+/include/linux/mmzone.h
@@ -604,6 +604,9 @@ typedef struct pglist_data {
int nr_zones;
#ifdef CONFIG_FLAT_NODE_MEM_MAP
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
@@ -932,6 +935,7 @@ static inline unsigned long early_pfn_to
#endif

struct page;
+struct page_cgroup;
struct mem_section {
/*
* This is, logically, a pointer to an array of struct
@@ -949,6 +953,10 @@ struct mem_section {

/* See declaration of similar field in struct zone */
unsigned long *pageblock_flags;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+ /* see page_cgroup.h */
+ struct page_cgroup *page_cgroup;
+#endif
};

#ifdef CONFIG_SPARSEMEM_EXTREME
Index: mmotm-2.6.27-rc6+/include/linux/memcontrol.h
===================================================================
--- mmotm-2.6.27-rc6+.orig/include/linux/memcontrol.h
+++ mmotm-2.6.27-rc6+/include/linux/memcontrol.h
@@ -29,7 +29,6 @@ struct mm_struct;

#define page_reset_bad_cgroup(page) ((page)->page_cgroup = 0)

-extern struct page_cgroup *page_get_page_cgroup(struct page *page);
extern int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
@@ -72,16 +71,8 @@ extern void mem_cgroup_record_reclaim_pr
extern long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
int priority, enum lru_list lru);

-#else /* CONFIG_CGROUP_MEM_RES_CTLR */
-static inline void page_reset_bad_cgroup(struct page *page)
-{
-}
-
-static inline struct page_cgroup *page_get_page_cgroup(struct page *page)
-{
- return NULL;
-}

+#else /* CONFIG_CGROUP_MEM_RES_CTLR */
static inline int mem_cgroup_charge(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask)
{