diff options
| -rw-r--r-- | include/linux/page_cgroup.h | 31 | ||||
| -rw-r--r-- | mm/memcontrol.c | 9 |
2 files changed, 35 insertions, 5 deletions
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index fdb5a92b5ac7..5b0c971d7cae 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h @@ -35,15 +35,18 @@ struct page_cgroup *lookup_page_cgroup(struct page *page); enum { /* flags for mem_cgroup */ - PCG_LOCK, /* page cgroup is locked */ + PCG_LOCK, /* Lock for pc->mem_cgroup and following bits. */ PCG_CACHE, /* charged as cache */ PCG_USED, /* this object is in use. */ - PCG_ACCT_LRU, /* page has been accounted for */ + PCG_MIGRATION, /* under page migration */ + /* flags for mem_cgroup and file and I/O status */ + PCG_MOVE_LOCK, /* For race between move_account v.s. following bits */ PCG_FILE_MAPPED, /* page is accounted as "mapped" */ PCG_FILE_DIRTY, /* page is dirty */ PCG_FILE_WRITEBACK, /* page is under writeback */ PCG_FILE_UNSTABLE_NFS, /* page is NFS unstable */ - PCG_MIGRATION, /* under page migration */ + /* No lock in page_cgroup */ + PCG_ACCT_LRU, /* page has been accounted for (under lru_lock) */ }; #define TESTPCGFLAG(uname, lname) \ @@ -117,6 +120,10 @@ static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc) static inline void lock_page_cgroup(struct page_cgroup *pc) { + /* + * Don't take this lock in IRQ context. + * This lock is for pc->mem_cgroup, USED, CACHE, MIGRATION + */ bit_spin_lock(PCG_LOCK, &pc->flags); } @@ -130,6 +137,24 @@ static inline int page_is_cgroup_locked(struct page_cgroup *pc) return bit_spin_is_locked(PCG_LOCK, &pc->flags); } +static inline void move_lock_page_cgroup(struct page_cgroup *pc, + unsigned long *flags) +{ + /* + * We know updates to pc->flags of page cache's stats are from both of + * usual context or IRQ context. Disable IRQ to avoid deadlock. + */ + local_irq_save(*flags); + bit_spin_lock(PCG_MOVE_LOCK, &pc->flags); +} + +static inline void move_unlock_page_cgroup(struct page_cgroup *pc, + unsigned long *flags) +{ + bit_spin_unlock(PCG_MOVE_LOCK, &pc->flags); + local_irq_restore(*flags); +} + #else /* CONFIG_CGROUP_MEM_RES_CTLR */ struct page_cgroup; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3d8a0c79dece..d888956a2cfc 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1606,6 +1606,7 @@ void mem_cgroup_update_page_stat(struct page *page, struct mem_cgroup *mem; struct page_cgroup *pc = lookup_page_cgroup(page); bool need_unlock = false; + unsigned long uninitialized_var(flags); if (unlikely(!pc)) return; @@ -1617,7 +1618,7 @@ void mem_cgroup_update_page_stat(struct page *page, /* pc->mem_cgroup is unstable ? */ if (unlikely(mem_cgroup_stealed(mem))) { /* take a lock against to access pc->mem_cgroup */ - lock_page_cgroup(pc); + move_lock_page_cgroup(pc, &flags); need_unlock = true; mem = pc->mem_cgroup; if (!mem || !PageCgroupUsed(pc)) @@ -1640,7 +1641,7 @@ void mem_cgroup_update_page_stat(struct page *page, out: if (unlikely(need_unlock)) - unlock_page_cgroup(pc); + move_unlock_page_cgroup(pc, &flags); rcu_read_unlock(); return; } @@ -2211,9 +2212,13 @@ static int mem_cgroup_move_account(struct page_cgroup *pc, struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge) { int ret = -EINVAL; + unsigned long flags; + lock_page_cgroup(pc); if (PageCgroupUsed(pc) && pc->mem_cgroup == from) { + move_lock_page_cgroup(pc, &flags); __mem_cgroup_move_account(pc, from, to, uncharge); + move_unlock_page_cgroup(pc, &flags); ret = 0; } unlock_page_cgroup(pc); |