From 9fb4b7cc0724f178d4b24a2a566ea1e7cb120b82 Mon Sep 17 00:00:00 2001 From: Bob Liu Date: Thu, 12 Jan 2012 17:18:48 -0800 Subject: [PATCH] page_cgroup: add helper function to get swap_cgroup There are multiple places which need to get the swap_cgroup address, so add a helper function: static struct swap_cgroup *swap_cgroup_getsc(swp_entry_t ent, struct swap_cgroup_ctrl **ctrl); to simplify the code. Signed-off-by: Bob Liu Acked-by: Michal Hocko Acked-by: KAMEZAWA Hiroyuki Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page_cgroup.h | 4 +-- mm/memcontrol.c | 4 +-- mm/page_cgroup.c | 56 +++++++++++++------------------------ 3 files changed, 24 insertions(+), 40 deletions(-) diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index aaa60da8783c..1153095ee457 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h @@ -149,7 +149,7 @@ static inline void __init page_cgroup_init_flatmem(void) extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent, unsigned short old, unsigned short new); extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id); -extern unsigned short lookup_swap_cgroup(swp_entry_t ent); +extern unsigned short lookup_swap_cgroup_id(swp_entry_t ent); extern int swap_cgroup_swapon(int type, unsigned long max_pages); extern void swap_cgroup_swapoff(int type); #else @@ -161,7 +161,7 @@ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) } static inline -unsigned short lookup_swap_cgroup(swp_entry_t ent) +unsigned short lookup_swap_cgroup_id(swp_entry_t ent) { return 0; } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 71a9774e6ead..4c53e971749e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2474,7 +2474,7 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) memcg = NULL; } else if (PageSwapCache(page)) { ent.val = page_private(page); - id = lookup_swap_cgroup(ent); + id = lookup_swap_cgroup_id(ent); rcu_read_lock(); memcg = mem_cgroup_lookup(id); if (memcg && !css_tryget(&memcg->css)) @@ -5264,7 +5264,7 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma, } /* There is a swap entry and a page doesn't exist or isn't charged */ if (ent.val && !ret && - css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { + css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) { ret = MC_TARGET_SWAP; if (target) target->ent = ent; diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c index e910524e5a08..b99d19edf89b 100644 --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -334,7 +334,6 @@ struct swap_cgroup { unsigned short id; }; #define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup)) -#define SC_POS_MASK (SC_PER_PAGE - 1) /* * SwapCgroup implements "lookup" and "exchange" operations. @@ -376,6 +375,21 @@ not_enough_page: return -ENOMEM; } +static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent, + struct swap_cgroup_ctrl **ctrlp) +{ + pgoff_t offset = swp_offset(ent); + struct swap_cgroup_ctrl *ctrl; + struct page *mappage; + + ctrl = &swap_cgroup_ctrl[swp_type(ent)]; + if (ctrlp) + *ctrlp = ctrl; + + mappage = ctrl->map[offset / SC_PER_PAGE]; + return page_address(mappage) + offset % SC_PER_PAGE; +} + /** * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry. * @end: swap entry to be cmpxchged @@ -388,21 +402,13 @@ not_enough_page: 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]; + sc = lookup_swap_cgroup(ent, &ctrl); - mappage = ctrl->map[idx]; - sc = page_address(mappage); - sc += pos; spin_lock_irqsave(&ctrl->lock, flags); retval = sc->id; if (retval == old) @@ -423,21 +429,13 @@ unsigned short swap_cgroup_cmpxchg(swp_entry_t ent, */ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) { - 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 short old; unsigned long flags; - ctrl = &swap_cgroup_ctrl[type]; + sc = lookup_swap_cgroup(ent, &ctrl); - mappage = ctrl->map[idx]; - sc = page_address(mappage); - sc += pos; spin_lock_irqsave(&ctrl->lock, flags); old = sc->id; sc->id = id; @@ -447,28 +445,14 @@ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) } /** - * lookup_swap_cgroup - lookup mem_cgroup tied to swap entry + * lookup_swap_cgroup_id - lookup mem_cgroup id tied to swap entry * @ent: swap entry to be looked up. * * Returns CSS ID of mem_cgroup at success. 0 at failure. (0 is invalid ID) */ -unsigned short lookup_swap_cgroup(swp_entry_t ent) +unsigned short lookup_swap_cgroup_id(swp_entry_t ent) { - 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 short ret; - - ctrl = &swap_cgroup_ctrl[type]; - mappage = ctrl->map[idx]; - sc = page_address(mappage); - sc += pos; - ret = sc->id; - return ret; + return lookup_swap_cgroup(ent, NULL)->id; } int swap_cgroup_swapon(int type, unsigned long max_pages) -- 2.20.1