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Message-Id: <20081001140748.637b9831.kamezawa.hiroyu@jp.fujitsu.com>
Date: Wed, 1 Oct 2008 14:07:48 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To: balbir@...ux.vnet.ibm.com
Cc: "linux-mm@...ck.org" <linux-mm@...ck.org>,
"nishimura@....nes.nec.co.jp" <nishimura@....nes.nec.co.jp>,
"xemul@...nvz.org" <xemul@...nvz.org>,
Andrew Morton <akpm@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>,
Dave Hansen <haveblue@...ibm.com>, ryov@...inux.co.jp
Subject: Re: [PATCH 9/12] memcg allocate all page_cgroup at boot
On Wed, 01 Oct 2008 09:33:53 +0530
Balbir Singh <balbir@...ux.vnet.ibm.com> wrote:
> > +int __meminit init_section_page_cgroup(unsigned long pfn)
> > +{
> > + struct mem_section *section;
> > + struct page_cgroup *base, *pc;
> > + unsigned long table_size;
> > + int nid, index;
> > +
> > + 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;
> > + base = kmalloc_node(table_size, GFP_KERNEL, nid);
> > + if (!base)
> > + base = vmalloc_node(table_size, nid);
>
> Should we check for slab_is_available() before calling kmalloc_node? Otherwise,
> we might need to fallback to alloc_bootmem_node.
>
That check is not necessary.
Because we use kmalloc()/vmalloc() in mem_cgroup_create(), after this.
(We assume usual page allocateor is available here. For FLATMEM, size of
array can be too big for kmalloc(), etc... I use alloc_bootmem().
> > +
> > + 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;
> > + total_usage += table_size;
> > + 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;
> > + if (is_vmalloc_addr(base))
> > + vfree(base);
> > + else
> > + kfree(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);
> > + }
> > + printk("allocated %ld bytes of page_cgroup\n", total_usage);
> > + printk("please try cgroup_disable=memory option if you don't want\n");
> > +}
> > +
> > +void __init pgdat_page_cgroup_init(struct pglist_data *pgdat)
> > +{
> > + return;
> > +}
> > +
> > +#endif
>
> I like this code very much, even though I've not tested it. I think it combines
> all we've been thinking and discussing very well (from my initial flatmem based
> code to Dave's suggestion of using mem_section).
>
> > Index: mmotm-2.6.27-rc7+/include/linux/mm_types.h
> > ===================================================================
> > --- mmotm-2.6.27-rc7+.orig/include/linux/mm_types.h
> > +++ mmotm-2.6.27-rc7+/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
> > -
>
> Yay! I think we should add some documentation saying, if you think about
> extending struct page, think again, look at how we did it for the memory
> controller (look at memcontrol.c and page_cgroup.c).
>
???? it's usually not accepted. I've seen such case very much.
I wonder why this was accepted ;)
> > #ifdef CONFIG_KMEMCHECK
> > void *shadow;
> > #endif
> > Index: mmotm-2.6.27-rc7+/mm/Makefile
> > ===================================================================
> > --- mmotm-2.6.27-rc7+.orig/mm/Makefile
> > +++ mmotm-2.6.27-rc7+/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-rc7+/include/linux/page_cgroup.h
> > ===================================================================
> > --- /dev/null
> > +++ mmotm-2.6.27-rc7+/include/linux/page_cgroup.h
> > @@ -0,0 +1,90 @@
> > +#ifndef __LINUX_PAGE_CGROUP_H
> > +#define __LINUX_PAGE_CGROUP_H
> > +#include <linux/bit_spinlock.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)
> > +
>
> Can we make this patch indepedent of the flags changes and push it in ASAP.
>
Need much work....Hmm..rewrite all again ?
> > +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-rc7+/mm/memcontrol.c
> > ===================================================================
> > --- mmotm-2.6.27-rc7+.orig/mm/memcontrol.c
> > +++ mmotm-2.6.27-rc7+/mm/memcontrol.c
> > @@ -35,11 +35,11 @@
> > #include <linux/vmalloc.h>
> > #include <linux/mm_inline.h>
> > #include <linux/writeback.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
> >
> > /*
> > @@ -139,80 +139,6 @@ 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,
> > @@ -223,9 +149,9 @@ 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,
> > };
> >
> > @@ -308,37 +234,6 @@ 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)
> > {
> > @@ -442,22 +337,19 @@ 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);
> > }
> >
> > /*
> > @@ -544,6 +436,8 @@ 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();
>
> I don't understand the preempt_disable() is it for atomic operations? I would
> like to split the removal of struct page from atomic operations for performance.
> I think it will make it easier to merge/review.
>
Memory hotremoval is not related to this.
This preempt_disable() is avoidance for deadlock. (I thought)
lock_page_cgroup();
-> spin_lock_irqsave(&mz->lru_lock);
-> spin_unlock_irqrestore(&mz->lru_lock);
unlock_page_cgroup();
After review, my current code drops this 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);
> > @@ -997,6 +885,8 @@ static void mem_cgroup_force_empty_list(
> > spin_lock_irqsave(&mz->lru_lock, flags);
> > list_for_each_entry_safe(pc, tmp, list, lru) {
> > page = pc->page;
> > + if (!PageCgroupUsed(pc))
> > + continue;
> > /* For avoiding race with speculative page cache handling. */
> > if (!PageLRU(page) || !get_page_unless_zero(page)) {
> > continue;
> > @@ -1270,8 +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-rc7+/mm/page_alloc.c
> > ===================================================================
> > --- mmotm-2.6.27-rc7+.orig/mm/page_alloc.c
> > +++ mmotm-2.6.27-rc7+/mm/page_alloc.c
> > @@ -44,7 +44,7 @@
> > #include <linux/backing-dev.h>
> > #include <linux/fault-inject.h>
> > #include <linux/page-isolation.h>
> > -#include <linux/memcontrol.h>
> > +#include <linux/page_cgroup.h>
> > #include <linux/debugobjects.h>
> >
> > #include <asm/tlbflush.h>
> > @@ -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-rc7+/include/linux/mmzone.h
> > ===================================================================
> > --- mmotm-2.6.27-rc7+.orig/include/linux/mmzone.h
> > +++ mmotm-2.6.27-rc7+/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 +953,11 @@ 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;
> > + unsigned long pad;
> > +#endif
> > };
> >
> > #ifdef CONFIG_SPARSEMEM_EXTREME
> > Index: mmotm-2.6.27-rc7+/include/linux/memcontrol.h
> > ===================================================================
> > --- mmotm-2.6.27-rc7+.orig/include/linux/memcontrol.h
> > +++ mmotm-2.6.27-rc7+/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)
> > {
> >
>
> Except for the the performance changes for atomic operations, I like this patch
> very much.
>
Did you see performance regression by atomic ops ?
I'll rewrite the whole stack from now for your request.
Thanks,
-Kame
> For the page removal portions
> Signed-off-by: Balbir Singh <balbir@...ux.vnet.ibm.com> as a co-maintainer
>
>
> --
> Balbir
>
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