diff options
Diffstat (limited to 'mm/page_cgroup.c')
| -rw-r--r-- | mm/page_cgroup.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c index 3d535d594826..6c0081441a32 100644 --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -284,6 +284,7 @@ static DEFINE_MUTEX(swap_cgroup_mutex); struct swap_cgroup_ctrl { struct page **map; unsigned long length; + spinlock_t lock; }; struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES]; @@ -335,6 +336,43 @@ not_enough_page: } /** + * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry. + * @end: swap entry to be cmpxchged + * @old: old id + * @new: new id + * + * Returns old id at success, 0 at failure. + * (There is no mem_cgroup useing 0 as its id) + */ +unsigned short swap_cgroup_cmpxchg(swp_entry_t ent, + unsigned short old, unsigned short new) +{ + int type = swp_type(ent); + unsigned long offset = swp_offset(ent); + unsigned long idx = offset / SC_PER_PAGE; + unsigned long pos = offset & SC_POS_MASK; + struct swap_cgroup_ctrl *ctrl; + struct page *mappage; + struct swap_cgroup *sc; + unsigned long flags; + unsigned short retval; + + ctrl = &swap_cgroup_ctrl[type]; + + mappage = ctrl->map[idx]; + sc = page_address(mappage); + sc += pos; + spin_lock_irqsave(&ctrl->lock, flags); + retval = sc->id; + if (retval == old) + sc->id = new; + else + retval = 0; + spin_unlock_irqrestore(&ctrl->lock, flags); + return retval; +} + +/** * swap_cgroup_record - record mem_cgroup for this swp_entry. * @ent: swap entry to be recorded into * @mem: mem_cgroup to be recorded @@ -352,14 +390,17 @@ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) struct page *mappage; struct swap_cgroup *sc; unsigned short old; + unsigned long flags; ctrl = &swap_cgroup_ctrl[type]; mappage = ctrl->map[idx]; sc = page_address(mappage); sc += pos; + spin_lock_irqsave(&ctrl->lock, flags); old = sc->id; sc->id = id; + spin_unlock_irqrestore(&ctrl->lock, flags); return old; } @@ -411,6 +452,7 @@ int swap_cgroup_swapon(int type, unsigned long max_pages) mutex_lock(&swap_cgroup_mutex); ctrl->length = length; ctrl->map = array; + spin_lock_init(&ctrl->lock); if (swap_cgroup_prepare(type)) { /* memory shortage */ ctrl->map = NULL; |