Commit a095a940 authored by Liu Shixin's avatar Liu Shixin Committed by Jinjiang Tu
Browse files

memcg: add restrict to swap to cgroup1 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8QK6Q


CVE: NA

--------------------------------

The memsw can't limit the usage of swap space. Add memory.swap.max
interface to limit the difference value of memsw.usage and memory.usage.
Since a page may occupy both swap entry and a swap cache page, this value
is not exactly equal to swap.usage.

Signed-off-by: default avatarLiu Shixin <liushixin2@huawei.com>
Signed-off-by: default avatarJinjiang Tu <tujinjiang@huawei.com>
parent 92a0eb9b

Documentation/admin-guide/cgroup-v1/memory.rst

+2 −0
Original line number Diff line number Diff line
@@ -84,6 +84,8 @@ Brief summary of control files. 
                                     used.

 memory.force_empty		     trigger forced page reclaim

 memory.force_swapin		     trigger forced swapin anon page

 memory.swap.max		     set/show limit for the difference between memsw.usage

				     and memory.usage

 memory.pressure_level		     set memory pressure notifications

 memory.swappiness		     set/show swappiness parameter of vmscan

				     (See sysctl's vm.swappiness)

include/linux/memcontrol.h

+8 −0
Original line number Diff line number Diff line
@@ -201,6 +201,10 @@ struct obj_cgroup { 
	};

};



struct swap_device {

	unsigned long max;

};



/*

 * The memory controller data structure. The memory controller controls both

 * page cache and RSS per cgroup. We would eventually like to provide
@@ -350,6 +354,10 @@ struct mem_cgroup { 
	bool high_async_reclaim;

#endif



#ifdef CONFIG_MEMCG_SWAP_QOS

	struct swap_device *swap_dev;

#endif



	struct mem_cgroup_per_node *nodeinfo[];

};

mm/memcontrol.c

+133 −1
Original line number Diff line number Diff line
@@ -4249,6 +4249,10 @@ static int sysctl_memcg_swap_qos_stat; 


static void memcg_swap_qos_reset(void)

{

	struct mem_cgroup *memcg;



	for_each_mem_cgroup(memcg)

		WRITE_ONCE(memcg->swap_dev->max, PAGE_COUNTER_MAX);

}



static int sysctl_memcg_swap_qos_handler(struct ctl_table *table, int write,
@@ -4309,6 +4313,122 @@ static ssize_t memory_swapin(struct kernfs_open_file *of, char *buf, 


	return nbytes;

}



static int memcg_alloc_swap_device(struct mem_cgroup *memcg)

{

	memcg->swap_dev = kmalloc(sizeof(struct swap_device), GFP_KERNEL);

	if (!memcg->swap_dev)

		return -ENOMEM;

	return 0;

}



static void memcg_free_swap_device(struct mem_cgroup *memcg)

{

	if (!memcg->swap_dev)

		return;



	kfree(memcg->swap_dev);

	memcg->swap_dev = NULL;

}



static void memcg_swap_device_init(struct mem_cgroup *memcg,

				   struct mem_cgroup *parent)

{

	if (!static_branch_likely(&memcg_swap_qos_key) || !parent)

		WRITE_ONCE(memcg->swap_dev->max, PAGE_COUNTER_MAX);

	else

		WRITE_ONCE(memcg->swap_dev->max,

			   READ_ONCE(parent->swap_dev->max));

}



u64 memcg_swapmax_read(struct cgroup_subsys_state *css, struct cftype *cft)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);



	if (!static_branch_likely(&memcg_swap_qos_key))

		return PAGE_COUNTER_MAX * PAGE_SIZE;



	return READ_ONCE(memcg->swap_dev->max) * PAGE_SIZE;

}



static ssize_t memcg_swapmax_write(struct kernfs_open_file *of,

				     char *buf, size_t nbytes, loff_t off)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));

	unsigned long max;

	int err;



	if (!static_branch_likely(&memcg_swap_qos_key))

		return -EACCES;



	buf = strstrip(buf);

	err = page_counter_memparse(buf, "max", &max);

	if (err)

		return err;



	WRITE_ONCE(memcg->swap_dev->max, max);



	return nbytes;

}



static int mem_cgroup_check_swap_for_v1(struct folio *folio, swp_entry_t entry)

{

	struct mem_cgroup *memcg, *target_memcg;

	unsigned long swap_usage;

	unsigned long swap_limit;

	long nr_swap_pages = PAGE_COUNTER_MAX;



	if (!static_branch_likely(&memcg_swap_qos_key))

		return 0;



	if (!entry.val)

		return 0;



	rcu_read_lock();

	target_memcg = folio_memcg(folio);

	if (!target_memcg || mem_cgroup_is_root(target_memcg) ||

		!css_tryget_online(&target_memcg->css)) {

		rcu_read_unlock();

		return 0;

	}



	rcu_read_unlock();



	for (memcg = target_memcg; memcg != root_mem_cgroup;

	     memcg = parent_mem_cgroup(memcg)) {

		swap_limit = READ_ONCE(memcg->swap_dev->max);

		swap_usage = page_counter_read(&memcg->memsw) -

			     page_counter_read(&memcg->memory);

		nr_swap_pages = min_t(long, nr_swap_pages,

				      swap_limit - swap_usage);

	}

	css_put(&target_memcg->css);



	if (folio_nr_pages(folio) > nr_swap_pages)

		return -ENOMEM;



	return 0;

}



#else

static int memcg_alloc_swap_device(struct mem_cgroup *memcg)

{

	return 0;

}



static void memcg_free_swap_device(struct mem_cgroup *memcg)

{

}



static void memcg_swap_device_init(struct mem_cgroup *memcg,

				   struct mem_cgroup *parent)

{

}



static int mem_cgroup_check_swap_for_v1(struct folio *folio, swp_entry_t entry)

{

	return 0;

}

#endif



#ifdef CONFIG_NUMA
@@ -5807,6 +5927,12 @@ static struct cftype mem_cgroup_legacy_files[] = { 
		.flags = CFTYPE_NOT_ON_ROOT,

		.write = memory_swapin,

	},

	{

		.name = "swap.max",

		.flags = CFTYPE_NOT_ON_ROOT,

		.write = memcg_swapmax_write,

		.read_u64 = memcg_swapmax_read,

	},

#endif

	{ },	/* terminate */

};
@@ -5943,6 +6069,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) 
		free_mem_cgroup_per_node_info(memcg, node);

	kfree(memcg->vmstats);

	free_percpu(memcg->vmstats_percpu);

	memcg_free_swap_device(memcg);

	kfree(memcg);

}
@@ -5964,6 +6091,9 @@ static struct mem_cgroup *mem_cgroup_alloc(void) 
	if (!memcg)

		return ERR_PTR(error);



	if (memcg_alloc_swap_device(memcg))

		goto fail;



	memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,

				 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);

	if (memcg->id.id < 0) {
@@ -6047,12 +6177,14 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 
		page_counter_init(&memcg->swap, &parent->swap);

		page_counter_init(&memcg->kmem, &parent->kmem);

		page_counter_init(&memcg->tcpmem, &parent->tcpmem);

		memcg_swap_device_init(memcg, parent);

	} else {

		init_memcg_events();

		page_counter_init(&memcg->memory, NULL);

		page_counter_init(&memcg->swap, NULL);

		page_counter_init(&memcg->kmem, NULL);

		page_counter_init(&memcg->tcpmem, NULL);

		memcg_swap_device_init(memcg, NULL);



		root_mem_cgroup = memcg;

		return &memcg->css;
@@ -8301,7 +8433,7 @@ int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry) 
	unsigned short oldid;



	if (do_memsw_account())

		return 0;

		return mem_cgroup_check_swap_for_v1(folio, entry);



	memcg = folio_memcg(folio);