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authorBob Liu <lliubbo@gmail.com>2012-01-12 17:18:48 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:07 -0800
commit9fb4b7cc0724f178d4b24a2a566ea1e7cb120b82 (patch)
tree0f2db9102d46f5e5c8492864fb1bd21f2e7cd768
parent40f23a21a8501c1b2c65c50c19b516488ac31313 (diff)
downloadlinaro-lsk-9fb4b7cc0724f178d4b24a2a566ea1e7cb120b82.tar.gz
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 <lliubbo@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/page_cgroup.h4
-rw-r--r--mm/memcontrol.c4
-rw-r--r--mm/page_cgroup.c56
3 files changed, 24 insertions, 40 deletions
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index aaa60da8783..1153095ee45 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 71a9774e6ea..4c53e971749 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 e910524e5a0..b99d19edf89 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)