8725d54162
Presently, memcg's FILE_MAPPED accounting has following race with
move_account (happens at rmdir()).
increment page->mapcount (rmap.c)
mem_cgroup_update_file_mapped() move_account()
lock_page_cgroup()
check page_mapped() if
page_mapped(page)>1 {
FILE_MAPPED -1 from old memcg
FILE_MAPPED +1 to old memcg
}
.....
overwrite pc->mem_cgroup
unlock_page_cgroup()
lock_page_cgroup()
FILE_MAPPED + 1 to pc->mem_cgroup
unlock_page_cgroup()
Then,
old memcg (-1 file mapped)
new memcg (+2 file mapped)
This happens because move_account see page_mapped() which is not guarded
by lock_page_cgroup(). This patch adds FILE_MAPPED flag to page_cgroup
and move account information based on it. Now, all checks are synchronous
with lock_page_cgroup().
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@in.ibm.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Andrea Righi <arighi@develer.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
159 lines
3.7 KiB
C
159 lines
3.7 KiB
C
#ifndef __LINUX_PAGE_CGROUP_H
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#define __LINUX_PAGE_CGROUP_H
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR
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#include <linux/bit_spinlock.h>
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/*
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* Page Cgroup can be considered as an extended mem_map.
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* A page_cgroup page is associated with every page descriptor. The
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* page_cgroup helps us identify information about the cgroup
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* All page cgroups are allocated at boot or memory hotplug event,
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* then the page cgroup for pfn always exists.
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*/
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struct page_cgroup {
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unsigned long flags;
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struct mem_cgroup *mem_cgroup;
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struct page *page;
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struct list_head lru; /* per cgroup LRU list */
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};
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void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat);
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#ifdef CONFIG_SPARSEMEM
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static inline void __init page_cgroup_init_flatmem(void)
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{
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}
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extern void __init page_cgroup_init(void);
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#else
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void __init page_cgroup_init_flatmem(void);
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static inline void __init page_cgroup_init(void)
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{
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}
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#endif
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struct page_cgroup *lookup_page_cgroup(struct page *page);
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enum {
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/* flags for mem_cgroup */
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PCG_LOCK, /* page cgroup is locked */
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PCG_CACHE, /* charged as cache */
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PCG_USED, /* this object is in use. */
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PCG_ACCT_LRU, /* page has been accounted for */
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PCG_FILE_MAPPED, /* page is accounted as "mapped" */
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};
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#define TESTPCGFLAG(uname, lname) \
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static inline int PageCgroup##uname(struct page_cgroup *pc) \
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{ return test_bit(PCG_##lname, &pc->flags); }
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#define SETPCGFLAG(uname, lname) \
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static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
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{ set_bit(PCG_##lname, &pc->flags); }
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#define CLEARPCGFLAG(uname, lname) \
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static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \
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{ clear_bit(PCG_##lname, &pc->flags); }
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#define TESTCLEARPCGFLAG(uname, lname) \
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static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \
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{ return test_and_clear_bit(PCG_##lname, &pc->flags); }
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TESTPCGFLAG(Locked, LOCK)
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/* Cache flag is set only once (at allocation) */
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TESTPCGFLAG(Cache, CACHE)
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CLEARPCGFLAG(Cache, CACHE)
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SETPCGFLAG(Cache, CACHE)
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TESTPCGFLAG(Used, USED)
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CLEARPCGFLAG(Used, USED)
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SETPCGFLAG(Used, USED)
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SETPCGFLAG(AcctLRU, ACCT_LRU)
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CLEARPCGFLAG(AcctLRU, ACCT_LRU)
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TESTPCGFLAG(AcctLRU, ACCT_LRU)
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TESTCLEARPCGFLAG(AcctLRU, ACCT_LRU)
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SETPCGFLAG(FileMapped, FILE_MAPPED)
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CLEARPCGFLAG(FileMapped, FILE_MAPPED)
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TESTPCGFLAG(FileMapped, FILE_MAPPED)
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static inline int page_cgroup_nid(struct page_cgroup *pc)
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{
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return page_to_nid(pc->page);
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}
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static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
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{
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return page_zonenum(pc->page);
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}
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static inline void lock_page_cgroup(struct page_cgroup *pc)
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{
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bit_spin_lock(PCG_LOCK, &pc->flags);
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}
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static inline void unlock_page_cgroup(struct page_cgroup *pc)
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{
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bit_spin_unlock(PCG_LOCK, &pc->flags);
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}
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#else /* CONFIG_CGROUP_MEM_RES_CTLR */
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struct page_cgroup;
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static inline void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
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{
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}
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static inline struct page_cgroup *lookup_page_cgroup(struct page *page)
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{
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return NULL;
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}
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static inline void page_cgroup_init(void)
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{
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}
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static inline void __init page_cgroup_init_flatmem(void)
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{
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}
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#endif
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#include <linux/swap.h>
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
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extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
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unsigned short old, unsigned short new);
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extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id);
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extern unsigned short lookup_swap_cgroup(swp_entry_t ent);
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extern int swap_cgroup_swapon(int type, unsigned long max_pages);
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extern void swap_cgroup_swapoff(int type);
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#else
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static inline
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unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
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{
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return 0;
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}
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static inline
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unsigned short lookup_swap_cgroup(swp_entry_t ent)
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{
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return 0;
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}
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static inline int
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swap_cgroup_swapon(int type, unsigned long max_pages)
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{
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return 0;
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}
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static inline void swap_cgroup_swapoff(int type)
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{
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return;
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}
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#endif
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#endif
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