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page_cgroup: add helper function to get swap_cgroup

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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>
This commit is contained in:
Bob Liu
2012-01-12 17:18:48 -08:00
committed by Linus Torvalds
parent 40f23a21a8
commit 9fb4b7cc07
3 changed files with 24 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
mm/page_cgroup.c
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@@ -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)