diff options
author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2008-10-18 20:28:16 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-20 08:52:39 -0700 |
commit | 52d4b9ac0b985168009c2a57098324e67bae171f (patch) | |
tree | b3e3b854166930af893be90ea30a7ab0d65c59e7 /mm/memcontrol.c | |
parent | c05555b572921c464d064d9267f7f7bc06d424fa (diff) | |
download | op-kernel-dev-52d4b9ac0b985168009c2a57098324e67bae171f.zip op-kernel-dev-52d4b9ac0b985168009c2a57098324e67bae171f.tar.gz |
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>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r-- | mm/memcontrol.c | 247 |
1 files changed, 80 insertions, 167 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 031682e..d4a92b6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -33,11 +33,11 @@ #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 /* @@ -135,79 +135,6 @@ struct mem_cgroup { }; static struct mem_cgroup 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, @@ -216,12 +143,18 @@ enum charge_type { NR_CHARGE_TYPE, }; +/* only for here (for easy reading.) */ +#define PCGF_CACHE (1UL << PCG_CACHE) +#define PCGF_USED (1UL << PCG_USED) +#define PCGF_ACTIVE (1UL << PCG_ACTIVE) +#define PCGF_LOCK (1UL << PCG_LOCK) +#define PCGF_FILE (1UL << PCG_FILE) 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)), - 0, + PCGF_CACHE | PCGF_FILE | PCGF_USED | PCGF_LOCK, /* File Cache */ + PCGF_ACTIVE | PCGF_USED | PCGF_LOCK, /* Anon */ + PCGF_ACTIVE | PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */ + 0, /* FORCE */ }; /* @@ -303,37 +236,6 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 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) { @@ -436,17 +338,16 @@ void mem_cgroup_move_lists(struct page *page, enum lru_list lru) * 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 (pc && PageCgroupUsed(pc)) { mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); __mem_cgroup_move_lists(pc, lru); spin_unlock_irqrestore(&mz->lru_lock, flags); } - unlock_page_cgroup(page); + unlock_page_cgroup(pc); } /* @@ -533,6 +434,8 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 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))) @@ -576,26 +479,27 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, { 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; } /* @@ -631,36 +535,33 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, } } + + lock_page_cgroup(pc); + if (unlikely(PageCgroupUsed(pc))) { + unlock_page_cgroup(pc); + res_counter_uncharge(&mem->res, PAGE_SIZE); + css_put(&mem->css); + + 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); - unlock_page_cgroup(page); done: return 0; out: css_put(&mem->css); - kmem_cache_free(page_cgroup_cache, pc); -err: return -ENOMEM; } @@ -668,7 +569,8 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { 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. @@ -689,7 +591,8 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, { 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 @@ -702,15 +605,16 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 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)) @@ -741,37 +645,39 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) /* * 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; - if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) - && ((PageCgroupCache(pc) || page_mapped(page)))) - goto unlock; + lock_page_cgroup(pc); + if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED && page_mapped(page)) + || !PageCgroupUsed(pc)) { + /* This happens at race in zap_pte_range() and do_swap_page()*/ + unlock_page_cgroup(pc); + return; + } + ClearPageCgroupUsed(pc); + mem = pc->mem_cgroup; mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); __mem_cgroup_remove_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); + unlock_page_cgroup(pc); - page_assign_page_cgroup(page, NULL); - unlock_page_cgroup(page); - - mem = pc->mem_cgroup; res_counter_uncharge(&mem->res, PAGE_SIZE); css_put(&mem->css); - kmem_cache_free(page_cgroup_cache, pc); return; -unlock: - unlock_page_cgroup(page); } void mem_cgroup_uncharge_page(struct page *page) { + /* early check. */ + if (page_mapped(page)) + return; + if (page->mapping && !PageAnon(page)) + return; __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); } @@ -795,9 +701,9 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage) 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)) { @@ -807,7 +713,7 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage) 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); @@ -832,7 +738,7 @@ void mem_cgroup_end_migration(struct page *newpage) */ if (!newpage->mapping) __mem_cgroup_uncharge_common(newpage, - MEM_CGROUP_CHARGE_TYPE_FORCE); + MEM_CGROUP_CHARGE_TYPE_FORCE); else if (PageAnon(newpage)) mem_cgroup_uncharge_page(newpage); } @@ -918,6 +824,8 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *mem, while (!list_empty(list)) { pc = list_entry(list->prev, struct page_cgroup, lru); page = pc->page; + if (!PageCgroupUsed(pc)) + break; get_page(page); spin_unlock_irqrestore(&mz->lru_lock, flags); /* @@ -932,8 +840,10 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *mem, count = FORCE_UNCHARGE_BATCH; cond_resched(); } - } else - cond_resched(); + } else { + spin_lock_irqsave(&mz->lru_lock, flags); + break; + } spin_lock_irqsave(&mz->lru_lock, flags); } spin_unlock_irqrestore(&mz->lru_lock, flags); @@ -957,6 +867,8 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem) while (mem->res.usage > 0) { if (atomic_read(&mem->css.cgroup->count) > 0) goto out; + /* This is for making all *used* pages to be on LRU. */ + lru_add_drain_all(); for_each_node_state(node, N_POSSIBLE) for (zid = 0; zid < MAX_NR_ZONES; zid++) { struct mem_cgroup_per_zone *mz; @@ -965,6 +877,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem) for_each_lru(l) mem_cgroup_force_empty_list(mem, mz, l); } + cond_resched(); } ret = 0; out: @@ -1175,8 +1088,8 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) 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) |