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Commit 9fb4b7cc authored by Bob Liu's avatar Bob Liu Committed by Linus Torvalds
Browse files

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: default avatarBob Liu <lliubbo@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 40f23a21

include/linux/page_cgroup.h

+2 −2
Original line number Diff line number Diff line
@@ -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;

}

mm/memcontrol.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

mm/page_cgroup.c

+20 −36
Original line number Diff line number Diff line
@@ -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 @@ static int swap_cgroup_prepare(int type) 
	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 @@ static int swap_cgroup_prepare(int type) 
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)