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SubjectRe: [PATCH 9/13] memcg: lookup page cgroup (and remove pointer from struct page)
After sleeping all day, I changed my mind and decided to drop this.
It seems no one like this.

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.

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.

Thanks,
-Kame


On Mon, 22 Sep 2008 20:12:06 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> Remove page_cgroup pointer from struct page.
>
> This patch removes page_cgroup pointer from struct page and make it be able
> to get from pfn. Then, relationship of them is
>
> Before this:
> pfn <-> struct page <-> struct page_cgroup.
> After this:
> struct page <-> pfn -> struct page_cgroup -> struct page.
>
> Benefit of this approach is we can remove 8 bytes from struct page.
>
> Other changes are:
> - lock/unlock_page_cgroup() uses its own bit on struct page_cgroup.
> - all necessary page_cgroups are allocated at boot.
>
> Characteristics:
> - page cgroup is allocated as some amount of chunk.
> This patch uses SECTION_SIZE as size of chunk if 64bit/SPARSEMEM is enabled.
> If not, appropriate default number is selected.
> - all page_cgroup struct is maintained by hash.
> I think we have 2 ways to handle sparse index in general
> ...radix-tree and hash. This uses hash because radix-tree's layout is
> affected by memory map's layout.
> - page_cgroup.h/page_cgroup.c is added.
>
> Changelog: v3 -> v4.
> - changed arguments to lookup_page_cgroup() from "pfn" to "page",
>
> Changelog: v2 -> v3
> - changed arguments from pfn to struct page*.
> - added memory hotplug callback (no undo...needs .more work.)
> - adjusted to new mmotm.
>
> Changelog: v1 -> v2
> - Fixed memory allocation failure at boot to do panic with good message.
> - rewrote charge/uncharge path (no changes in logic.)
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>
> include/linux/mm_types.h | 4
> include/linux/page_cgroup.h | 89 +++++++++++++++
> mm/Makefile | 2
> mm/memcontrol.c | 251 +++++++++++---------------------------------
> mm/page_alloc.c | 9 -
> mm/page_cgroup.c | 235 +++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 394 insertions(+), 196 deletions(-)
>
> Index: mmotm-2.6.27-rc6+/mm/page_cgroup.c
> ===================================================================
> --- /dev/null
> +++ mmotm-2.6.27-rc6+/mm/page_cgroup.c
> @@ -0,0 +1,235 @@
> +#include <linux/mm.h>
> +#include <linux/rcupdate.h>
> +#include <linux/rculist.h>
> +#include <linux/bootmem.h>
> +#include <linux/bit_spinlock.h>
> +#include <linux/page_cgroup.h>
> +#include <linux/hash.h>
> +#include <linux/memory.h>
> +
> +
> +
> +struct pcg_hash_head {
> + spinlock_t lock;
> + struct hlist_head head;
> +};
> +
> +static struct pcg_hash_head *pcg_hashtable __read_mostly;
> +
> +struct pcg_hash {
> + struct hlist_node node;
> + unsigned long index;
> + struct page_cgroup *map;
> +};
> +
> +#if BITS_PER_LONG == 32 /* we use kmalloc() */
> +#define ENTS_PER_CHUNK_SHIFT (7)
> +const bool chunk_vmalloc = false;
> +#else /* we'll use vmalloc */
> +#ifdef SECTION_SIZE_BITS
> +#define ENTS_PER_CHUNK_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT)
> +#else
> +#define ENTS_PER_CHUNK_SHIFT (14) /* covers 128MB on x86-64 */
> +#endif
> +const bool chunk_vmalloc = true;
> +#endif
> +
> +#define ENTS_PER_CHUNK (1 << (ENTS_PER_CHUNK_SHIFT))
> +#define ENTS_PER_CHUNK_MASK (ENTS_PER_CHUNK - 1)
> +
> +static int pcg_hashshift __read_mostly;
> +static int pcg_hashmask __read_mostly;
> +
> +#define PCG_HASHSHIFT (pcg_hashshift)
> +#define PCG_HASHMASK (pcg_hashmask)
> +#define PCG_HASHSIZE (1 << pcg_hashshift)
> +
> +static int pcg_hashfun(unsigned long index)
> +{
> + return hash_long(index, pcg_hashshift);
> +}
> +
> +struct page_cgroup *lookup_page_cgroup(unsigned long pfn)
> +{
> + unsigned long index = pfn >> ENTS_PER_CHUNK_SHIFT;
> + struct pcg_hash *ent;
> + struct pcg_hash_head *head;
> + struct hlist_node *node;
> + struct page_cgroup *pc = NULL;
> + int hnum;
> +
> + hnum = pcg_hashfun(index);
> + head = pcg_hashtable + hnum;
> + rcu_read_lock();
> + hlist_for_each_entry(ent, node, &head->head, node) {
> + if (ent->index == index) {
> + pc = ent->map + pfn;
> + break;
> + }
> + }
> + rcu_read_unlock();
> + return pc;
> +}
> +
> +static int __meminit alloc_page_cgroup(int node, unsigned long index)
> +{
> + struct pcg_hash *ent;
> + struct pcg_hash_head *head;
> + struct page_cgroup *pc;
> + unsigned long flags, base;
> + int hnum, i;
> + int mapsize = sizeof(struct page_cgroup) * ENTS_PER_CHUNK;
> +
> + if (lookup_page_cgroup(index << ENTS_PER_CHUNK_SHIFT))
> + return 0;
> +
> + if (!chunk_vmalloc) {
> + int ent_size = sizeof(*ent) + mapsize;
> + ent = kmalloc_node(ent_size, GFP_KERNEL, node);
> + if (!ent)
> + return 1;
> + pc = (void *)(ent + 1);
> + } else {
> + ent = kmalloc_node(sizeof(*ent), GFP_KERNEL, node);
> + if (!ent)
> + return 1;
> + pc = vmalloc_node(mapsize, node);
> + if (!pc) {
> + kfree(ent);
> + return 1;
> + }
> + }
> + ent->map = pc - (index << ENTS_PER_CHUNK_SHIFT);
> + ent->index = index;
> + INIT_HLIST_NODE(&ent->node);
> +
> + for (base = index << ENTS_PER_CHUNK_SHIFT, i = 0;
> + i < ENTS_PER_CHUNK; i++) {
> + unsigned long pfn = base + i;
> + pc = ent->map + pfn;
> + pc->page = pfn_to_page(pfn);
> + pc->mem_cgroup = NULL;
> + pc->flags = 0;
> + }
> +
> + hnum = pcg_hashfun(index);
> + head = &pcg_hashtable[hnum];
> + spin_lock_irqsave(&head->lock, flags);
> + hlist_add_head_rcu(&ent->node, &head->head);
> + spin_unlock_irqrestore(&head->lock, flags);
> + return 0;
> +}
> +
> +#ifdef CONFIG_MEMORY_HOTPLUG
> +
> +int online_page_cgroup(unsigned long start_pfn,
> + unsigned long nr_pages,
> + int nid)
> +{
> + unsigned long index, end_pfn, start, end;
> + int fail = 0;
> +
> + end_pfn = start_pfn + nr_pages;
> + start = start_pfn >> ENTS_PER_CHUNK_SHIFT;
> + end = (end_pfn + ENTS_PER_CHUNK - 1) >> ENTS_PER_CHUNK_SHIFT;
> +
> + for (index = start; (!fail) && (index < end); index++) {
> + unsigned long pfn = index << ENTS_PER_CHUNK_SHIFT;
> + if (lookup_page_cgroup(pfn))
> + continue;
> + fail = alloc_page_cgroup(nid, index);
> + }
> + return fail;
> +}
> +
> +static int pcg_memory_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_GOING_OFFLINE:
> + break;
> + case MEM_CANCEL_ONLINE:
> + case MEM_OFFLINE:
> + case MEM_ONLINE:
> + case MEM_CANCEL_OFFLINE:
> + break;
> + }
> + ret = notifier_from_errno(ret);
> + return ret;
> +}
> +
> +#endif
> +
> +/* Called From mem_cgroup's initilization */
> +void __init page_cgroup_init(void)
> +{
> + struct pcg_hash_head *head;
> + int node, i, fail;
> + unsigned long start, pfn, end, index, offset;
> + long default_pcg_hash_size;
> +
> + /* we don't need too large hash */
> + default_pcg_hash_size = (max_pfn/ENTS_PER_CHUNK);
> + default_pcg_hash_size *= 2;
> + /* if too big, use automatic calclation */
> + if (default_pcg_hash_size > 1024 * 1024)
> + default_pcg_hash_size = 0;
> +
> + pcg_hashtable = alloc_large_system_hash("PageCgroup Hash",
> + sizeof(struct pcg_hash_head),
> + default_pcg_hash_size,
> + 13,
> + 0,
> + &pcg_hashshift,
> + &pcg_hashmask,
> + 0);
> + if (!pcg_hashtable) {
> + fail = 1;
> + goto nomem;
> + }
> +
> + for (i = 0; i < PCG_HASHSIZE; i++) {
> + head = &pcg_hashtable[i];
> + spin_lock_init(&head->lock);
> + INIT_HLIST_HEAD(&head->head);
> + }
> +
> + fail = 0;
> + for_each_node(node) {
> + start = NODE_DATA(node)->node_start_pfn;
> + end = start + NODE_DATA(node)->node_spanned_pages;
> + start >>= ENTS_PER_CHUNK_SHIFT;
> + end = (end + ENTS_PER_CHUNK - 1) >> ENTS_PER_CHUNK_SHIFT;
> + for (index = start; (!fail) && (index < end); index++) {
> + pfn = index << ENTS_PER_CHUNK_SHIFT;
> + /*
> + * In usual, this loop breaks at offset=0.
> + * Handle a case a hole in MAX_ORDER (ia64 only...)
> + */
> + for (offset = 0; offset < ENTS_PER_CHUNK; offset++) {
> + if (pfn_valid(pfn + offset)) {
> + fail = alloc_page_cgroup(node, index);
> + break;
> + }
> + }
> + }
> + if (fail)
> + break;
> + }
> +
> + hotplug_memory_notifier(pcg_memory_callback, 0);
> +nomem:
> + if (fail) {
> + printk("Not enough memory for memory resource controller.\n");
> + panic("please try cgroup_disable=memory boot option.");
> + }
> + return;
> +}
> +
> +
> 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 +1,89 @@
> +#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 page_cgroup_init(void);
> +struct page_cgroup *lookup_page_cgroup(unsigned long pfn);
> +
> +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_to_pfn(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_to_pfn(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_to_pfn(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))
> @@ -808,53 +704,46 @@ __mem_cgroup_uncharge_common(struct page
> struct page_cgroup *pc;
> struct mem_cgroup *mem;
> struct mem_cgroup_per_zone *mz;
> + unsigned long pfn = page_to_pfn(page);
> unsigned long flags;
>
> 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(pfn);
> + 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 +767,9 @@ 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_to_pfn(page));
> + lock_page_cgroup(pc);
> + if (PageCgroupUsed(pc)) {
> mem = pc->mem_cgroup;
> css_get(&mem->css);
> if (PageCgroupCache(pc)) {
> @@ -890,7 +779,7 @@ 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 +1160,8 @@ 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);
>
>



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  Last update: 2008-09-24 01:45    [from the cache]
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