mm/memcontrol.c - kernel/msm-5.4 - Gitiles

 /* memcontrol.c - Memory Controller
  *
  * Copyright IBM Corporation, 2007
  * Author Balbir Singh <balbir@linux.vnet.ibm.com>
  *
  * Copyright 2007 OpenVZ SWsoft Inc
  * Author: Pavel Emelianov <xemul@openvz.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/res_counter.h>
 #include <linux/memcontrol.h>
 #include <linux/cgroup.h>
 #include <linux/mm.h>
 #include <linux/page-flags.h>
 #include <linux/bit_spinlock.h>
 #include <linux/rcupdate.h>

 struct cgroup_subsys mem_cgroup_subsys;

 /*
  * The memory controller data structure. The memory controller controls both
  * page cache and RSS per cgroup. We would eventually like to provide
  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
  * to help the administrator determine what knobs to tune.
  *
  * TODO: Add a water mark for the memory controller. Reclaim will begin when
  * we hit the water mark. May be even add a low water mark, such that
  * no reclaim occurs from a cgroup at it's low water mark, this is
  * a feature that will be implemented much later in the future.
  */
 struct mem_cgroup {
 	struct cgroup_subsys_state css;
 	/*
 	 * the counter to account for memory usage
 	 */
 	struct res_counter res;
 	/*
 	 * Per cgroup active and inactive list, similar to the
 	 * per zone LRU lists.
 	 * TODO: Consider making these lists per zone
 	 */
 	struct list_head active_list;
 	struct list_head inactive_list;
 };

 /*
  * We use the lower bit of the page->page_cgroup pointer as a bit spin
  * lock. We need to ensure that page->page_cgroup is atleast two
  * byte aligned (based on comments from Nick Piggin)
  */
 #define PAGE_CGROUP_LOCK_BIT 	0x0
 #define PAGE_CGROUP_LOCK 		(1 << PAGE_CGROUP_LOCK_BIT)

 /*
  * A page_cgroup page is associated with every page descriptor. The
  * page_cgroup helps us identify information about the cgroup
  */
 struct page_cgroup {
 	struct list_head lru;		/* per cgroup LRU list */
 	struct page *page;
 	struct mem_cgroup *mem_cgroup;
 	atomic_t ref_cnt;		/* Helpful when pages move b/w  */
 					/* mapped and cached states     */
 };


 static inline
 struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
 {
 	return container_of(cgroup_subsys_state(cont,
 				mem_cgroup_subsys_id), struct mem_cgroup,
 				css);
 }

 static inline
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
 {
 	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
 				struct mem_cgroup, css);
 }

 void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
 {
 	struct mem_cgroup *mem;

 	mem = mem_cgroup_from_task(p);
 	css_get(&mem->css);
 	mm->mem_cgroup = mem;
 }

 void mm_free_cgroup(struct mm_struct *mm)
 {
 	css_put(&mm->mem_cgroup->css);
 }

 static inline int page_cgroup_locked(struct page *page)
 {
 	return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT,
 					&page->page_cgroup);
 }

 void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
 {
 	int locked;

 	/*
 	 * While resetting the page_cgroup we might not hold the
 	 * page_cgroup lock. free_hot_cold_page() is an example
 	 * of such a scenario
 	 */
 	if (pc)
 		VM_BUG_ON(!page_cgroup_locked(page));
 	locked = (page->page_cgroup & PAGE_CGROUP_LOCK);
 	page->page_cgroup = ((unsigned long)pc | locked);
 }

 struct page_cgroup *page_get_page_cgroup(struct page *page)
 {
 	return (struct page_cgroup *)
 		(page->page_cgroup & ~PAGE_CGROUP_LOCK);
 }

 void __always_inline lock_page_cgroup(struct page *page)
 {
 	bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 	VM_BUG_ON(!page_cgroup_locked(page));
 }

 void __always_inline unlock_page_cgroup(struct page *page)
 {
 	bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
 }

 /*
  * Charge the memory controller for page usage.
  * Return
  * 0 if the charge was successful
  * < 0 if the cgroup is over its limit
  */
 int mem_cgroup_charge(struct page *page, struct mm_struct *mm)
 {
 	struct mem_cgroup *mem;
 	struct page_cgroup *pc, *race_pc;

 	/*
 	 * Should page_cgroup's go to their own slab?
 	 * One could optimize the performance of the charging routine
 	 * by saving a bit in the page_flags and using it as a lock
 	 * to see if the cgroup page already has a page_cgroup associated
 	 * with it
 	 */
 	lock_page_cgroup(page);
 	pc = page_get_page_cgroup(page);
 	/*
 	 * The page_cgroup exists and the page has already been accounted
 	 */
 	if (pc) {
 		atomic_inc(&pc->ref_cnt);
 		goto done;
 	}

 	unlock_page_cgroup(page);

 	pc = kzalloc(sizeof(struct page_cgroup), GFP_KERNEL);
 	if (pc == NULL)
 		goto err;

 	rcu_read_lock();
 	/*
 	 * We always charge the cgroup the mm_struct belongs to
 	 * the mm_struct's mem_cgroup changes on task migration if the
 	 * thread group leader migrates. It's possible that mm is not
 	 * set, if so charge the init_mm (happens for pagecache usage).
 	 */
 	if (!mm)
 		mm = &init_mm;

 	mem = rcu_dereference(mm->mem_cgroup);
 	/*
 	 * For every charge from the cgroup, increment reference
 	 * count
 	 */
 	css_get(&mem->css);
 	rcu_read_unlock();

 	/*
 	 * If we created the page_cgroup, we should free it on exceeding
 	 * the cgroup limit.
 	 */
 	if (res_counter_charge(&mem->res, 1)) {
 		css_put(&mem->css);
 		goto free_pc;
 	}

 	lock_page_cgroup(page);
 	/*
 	 * Check if somebody else beat us to allocating the page_cgroup
 	 */
 	race_pc = page_get_page_cgroup(page);
 	if (race_pc) {
 		kfree(pc);
 		pc = race_pc;
 		atomic_inc(&pc->ref_cnt);
 		res_counter_uncharge(&mem->res, 1);
 		css_put(&mem->css);
 		goto done;
 	}

 	atomic_set(&pc->ref_cnt, 1);
 	pc->mem_cgroup = mem;
 	pc->page = page;
 	page_assign_page_cgroup(page, pc);

 done:
 	unlock_page_cgroup(page);
 	return 0;
 free_pc:
 	kfree(pc);
 	return -ENOMEM;
 err:
 	unlock_page_cgroup(page);
 	return -ENOMEM;
 }

 /*
  * Uncharging is always a welcome operation, we never complain, simply
  * uncharge.
  */
 void mem_cgroup_uncharge(struct page_cgroup *pc)
 {
 	struct mem_cgroup *mem;
 	struct page *page;

 	if (!pc)
 		return;

 	if (atomic_dec_and_test(&pc->ref_cnt)) {
 		page = pc->page;
 		lock_page_cgroup(page);
 		mem = pc->mem_cgroup;
 		css_put(&mem->css);
 		page_assign_page_cgroup(page, NULL);
 		unlock_page_cgroup(page);
 		res_counter_uncharge(&mem->res, 1);
 		kfree(pc);
 	}
 }

 static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,
 			struct file *file, char __user *userbuf, size_t nbytes,
 			loff_t *ppos)
 {
 	return res_counter_read(&mem_cgroup_from_cont(cont)->res,
 				cft->private, userbuf, nbytes, ppos);
 }

 static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 				struct file *file, const char __user *userbuf,
 				size_t nbytes, loff_t *ppos)
 {
 	return res_counter_write(&mem_cgroup_from_cont(cont)->res,
 				cft->private, userbuf, nbytes, ppos);
 }

 static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "usage",
 		.private = RES_USAGE,
 		.read = mem_cgroup_read,
 	},
 	{
 		.name = "limit",
 		.private = RES_LIMIT,
 		.write = mem_cgroup_write,
 		.read = mem_cgroup_read,
 	},
 	{
 		.name = "failcnt",
 		.private = RES_FAILCNT,
 		.read = mem_cgroup_read,
 	},
 };

 static struct mem_cgroup init_mem_cgroup;

 static struct cgroup_subsys_state *
 mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 {
 	struct mem_cgroup *mem;

 	if (unlikely((cont->parent) == NULL)) {
 		mem = &init_mem_cgroup;
 		init_mm.mem_cgroup = mem;
 	} else
 		mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);

 	if (mem == NULL)
 		return NULL;

 	res_counter_init(&mem->res);
 	INIT_LIST_HEAD(&mem->active_list);
 	INIT_LIST_HEAD(&mem->inactive_list);
 	return &mem->css;
 }

 static void mem_cgroup_destroy(struct cgroup_subsys *ss,
 				struct cgroup *cont)
 {
 	kfree(mem_cgroup_from_cont(cont));
 }

 static int mem_cgroup_populate(struct cgroup_subsys *ss,
 				struct cgroup *cont)
 {
 	return cgroup_add_files(cont, ss, mem_cgroup_files,
 					ARRAY_SIZE(mem_cgroup_files));
 }

 struct cgroup_subsys mem_cgroup_subsys = {
 	.name = "memory",
 	.subsys_id = mem_cgroup_subsys_id,
 	.create = mem_cgroup_create,
 	.destroy = mem_cgroup_destroy,
 	.populate = mem_cgroup_populate,
 	.early_init = 1,
 };
	/* memcontrol.c - Memory Controller
	*
	* Copyright IBM Corporation, 2007
	* Author Balbir Singh <balbir@linux.vnet.ibm.com>
	*
	* Copyright 2007 OpenVZ SWsoft Inc
	* Author: Pavel Emelianov <xemul@openvz.org>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/res_counter.h>
	#include <linux/memcontrol.h>
	#include <linux/cgroup.h>
	#include <linux/mm.h>
	#include <linux/page-flags.h>
	#include <linux/bit_spinlock.h>
	#include <linux/rcupdate.h>

	struct cgroup_subsys mem_cgroup_subsys;

	/*
	* The memory controller data structure. The memory controller controls both
	* page cache and RSS per cgroup. We would eventually like to provide
	* statistics based on the statistics developed by Rik Van Riel for clock-pro,
	* to help the administrator determine what knobs to tune.
	*
	* TODO: Add a water mark for the memory controller. Reclaim will begin when
	* we hit the water mark. May be even add a low water mark, such that
	* no reclaim occurs from a cgroup at it's low water mark, this is
	* a feature that will be implemented much later in the future.
	*/
	struct mem_cgroup {
	struct cgroup_subsys_state css;
	/*
	* the counter to account for memory usage
	*/
	struct res_counter res;
	/*
	* Per cgroup active and inactive list, similar to the
	* per zone LRU lists.
	* TODO: Consider making these lists per zone
	*/
	struct list_head active_list;
	struct list_head inactive_list;
	};

	/*
	* We use the lower bit of the page->page_cgroup pointer as a bit spin
	* lock. We need to ensure that page->page_cgroup is atleast two
	* byte aligned (based on comments from Nick Piggin)
	*/
	#define PAGE_CGROUP_LOCK_BIT 0x0
	#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)

	/*
	* A page_cgroup page is associated with every page descriptor. The
	* page_cgroup helps us identify information about the cgroup
	*/
	struct page_cgroup {
	struct list_head lru; /* per cgroup LRU list */
	struct page *page;
	struct mem_cgroup *mem_cgroup;
	atomic_t ref_cnt; /* Helpful when pages move b/w */
	/* mapped and cached states */
	};


	static inline
	struct mem_cgroup mem_cgroup_from_cont(struct cgroup cont)
	{
	return container_of(cgroup_subsys_state(cont,
	mem_cgroup_subsys_id), struct mem_cgroup,
	css);
	}

	static inline
	struct mem_cgroup mem_cgroup_from_task(struct task_struct p)
	{
	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
	struct mem_cgroup, css);
	}

	void mm_init_cgroup(struct mm_struct mm, struct task_struct p)
	{
	struct mem_cgroup *mem;

	mem = mem_cgroup_from_task(p);
	css_get(&mem->css);
	mm->mem_cgroup = mem;
	}

	void mm_free_cgroup(struct mm_struct *mm)
	{
	css_put(&mm->mem_cgroup->css);
	}

	static inline int page_cgroup_locked(struct page *page)
	{
	return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT,
	&page->page_cgroup);
	}

	void page_assign_page_cgroup(struct page page, struct page_cgroup pc)
	{
	int locked;

	/*
	* While resetting the page_cgroup we might not hold the
	* page_cgroup lock. free_hot_cold_page() is an example
	* of such a scenario
	*/
	if (pc)
	VM_BUG_ON(!page_cgroup_locked(page));
	locked = (page->page_cgroup & PAGE_CGROUP_LOCK);
	page->page_cgroup = ((unsigned long)pc \| locked);
	}

	struct page_cgroup page_get_page_cgroup(struct page page)
	{
	return (struct page_cgroup *)
	(page->page_cgroup & ~PAGE_CGROUP_LOCK);
	}

	void __always_inline lock_page_cgroup(struct page *page)
	{
	bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
	VM_BUG_ON(!page_cgroup_locked(page));
	}

	void __always_inline unlock_page_cgroup(struct page *page)
	{
	bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
	}

	/*
	* Charge the memory controller for page usage.
	* Return
	* 0 if the charge was successful
	* < 0 if the cgroup is over its limit
	*/
	int mem_cgroup_charge(struct page page, struct mm_struct mm)
	{
	struct mem_cgroup *mem;
	struct page_cgroup pc, race_pc;

	/*
	* Should page_cgroup's go to their own slab?
	* One could optimize the performance of the charging routine
	* by saving a bit in the page_flags and using it as a lock
	* to see if the cgroup page already has a page_cgroup associated
	* with it
	*/
	lock_page_cgroup(page);
	pc = page_get_page_cgroup(page);
	/*
	* The page_cgroup exists and the page has already been accounted
	*/
	if (pc) {
	atomic_inc(&pc->ref_cnt);
	goto done;
	}

	unlock_page_cgroup(page);

	pc = kzalloc(sizeof(struct page_cgroup), GFP_KERNEL);
	if (pc == NULL)
	goto err;

	rcu_read_lock();
	/*
	* We always charge the cgroup the mm_struct belongs to
	* the mm_struct's mem_cgroup changes on task migration if the
	* thread group leader migrates. It's possible that mm is not
	* set, if so charge the init_mm (happens for pagecache usage).
	*/
	if (!mm)
	mm = &init_mm;

	mem = rcu_dereference(mm->mem_cgroup);
	/*
	* For every charge from the cgroup, increment reference
	* count
	*/
	css_get(&mem->css);
	rcu_read_unlock();

	/*
	* If we created the page_cgroup, we should free it on exceeding
	* the cgroup limit.
	*/
	if (res_counter_charge(&mem->res, 1)) {
	css_put(&mem->css);
	goto free_pc;
	}

	lock_page_cgroup(page);
	/*
	* Check if somebody else beat us to allocating the page_cgroup
	*/
	race_pc = page_get_page_cgroup(page);
	if (race_pc) {
	kfree(pc);
	pc = race_pc;
	atomic_inc(&pc->ref_cnt);
	res_counter_uncharge(&mem->res, 1);
	css_put(&mem->css);
	goto done;
	}

	atomic_set(&pc->ref_cnt, 1);
	pc->mem_cgroup = mem;
	pc->page = page;
	page_assign_page_cgroup(page, pc);

	done:
	unlock_page_cgroup(page);
	return 0;
	free_pc:
	kfree(pc);
	return -ENOMEM;
	err:
	unlock_page_cgroup(page);
	return -ENOMEM;
	}

	/*
	* Uncharging is always a welcome operation, we never complain, simply
	* uncharge.
	*/
	void mem_cgroup_uncharge(struct page_cgroup *pc)
	{
	struct mem_cgroup *mem;
	struct page *page;

	if (!pc)
	return;

	if (atomic_dec_and_test(&pc->ref_cnt)) {
	page = pc->page;
	lock_page_cgroup(page);
	mem = pc->mem_cgroup;
	css_put(&mem->css);
	page_assign_page_cgroup(page, NULL);
	unlock_page_cgroup(page);
	res_counter_uncharge(&mem->res, 1);
	kfree(pc);
	}
	}

	static ssize_t mem_cgroup_read(struct cgroup cont, struct cftype cft,
	struct file file, char __user userbuf, size_t nbytes,
	loff_t *ppos)
	{
	return res_counter_read(&mem_cgroup_from_cont(cont)->res,
	cft->private, userbuf, nbytes, ppos);
	}

	static ssize_t mem_cgroup_write(struct cgroup cont, struct cftype cft,
	struct file file, const char __user userbuf,
	size_t nbytes, loff_t *ppos)
	{
	return res_counter_write(&mem_cgroup_from_cont(cont)->res,
	cft->private, userbuf, nbytes, ppos);
	}

	static struct cftype mem_cgroup_files[] = {
	{
	.name = "usage",
	.private = RES_USAGE,
	.read = mem_cgroup_read,
	},
	{
	.name = "limit",
	.private = RES_LIMIT,
	.write = mem_cgroup_write,
	.read = mem_cgroup_read,
	},
	{
	.name = "failcnt",
	.private = RES_FAILCNT,
	.read = mem_cgroup_read,
	},
	};

	static struct mem_cgroup init_mem_cgroup;

	static struct cgroup_subsys_state *
	mem_cgroup_create(struct cgroup_subsys ss, struct cgroup cont)
	{
	struct mem_cgroup *mem;

	if (unlikely((cont->parent) == NULL)) {
	mem = &init_mem_cgroup;
	init_mm.mem_cgroup = mem;
	} else
	mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);

	if (mem == NULL)
	return NULL;

	res_counter_init(&mem->res);
	INIT_LIST_HEAD(&mem->active_list);
	INIT_LIST_HEAD(&mem->inactive_list);
	return &mem->css;
	}

	static void mem_cgroup_destroy(struct cgroup_subsys *ss,
	struct cgroup *cont)
	{
	kfree(mem_cgroup_from_cont(cont));
	}

	static int mem_cgroup_populate(struct cgroup_subsys *ss,
	struct cgroup *cont)
	{
	return cgroup_add_files(cont, ss, mem_cgroup_files,
	ARRAY_SIZE(mem_cgroup_files));
	}

	struct cgroup_subsys mem_cgroup_subsys = {
	.name = "memory",
	.subsys_id = mem_cgroup_subsys_id,
	.create = mem_cgroup_create,
	.destroy = mem_cgroup_destroy,
	.populate = mem_cgroup_populate,
	.early_init = 1,
	};