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Commit af36f906 authored by Tejun Heo's avatar Tejun Heo
Browse files

memcg: always create memsw files if CONFIG_CGROUP_MEM_RES_CTLR_SWAP 



Instead of conditioning creation of memsw files on do_swap_account,
always create the files if compiled-in and fail read/write attempts
with -EOPNOTSUPP if !do_swap_account.

This is suggested by KAMEZAWA to simplify memcg file creation so that
it can use cgroup->subsys_cftypes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
parent 4baf6e33

mm/memcontrol.c

+31 −34
Original line number Diff line number Diff line
@@ -3879,14 +3879,21 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) 
	return val << PAGE_SHIFT;

}



static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)

static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,

			       struct file *file, char __user *buf,

			       size_t nbytes, loff_t *ppos)

{

	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);

	char str[64];

	u64 val;

	int type, name;

	int type, name, len;



	type = MEMFILE_TYPE(cft->private);

	name = MEMFILE_ATTR(cft->private);



	if (!do_swap_account && type == _MEMSWAP)

		return -EOPNOTSUPP;



	switch (type) {

	case _MEM:

		if (name == RES_USAGE)
@@ -3903,7 +3910,9 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) 
	default:

		BUG();

	}

	return val;



	len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);

	return simple_read_from_buffer(buf, nbytes, ppos, str, len);

}

/*

 * The user of this function is...
@@ -3919,6 +3928,10 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, 


	type = MEMFILE_TYPE(cft->private);

	name = MEMFILE_ATTR(cft->private);



	if (!do_swap_account && type == _MEMSWAP)

		return -EOPNOTSUPP;



	switch (name) {

	case RES_LIMIT:

		if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
@@ -3984,12 +3997,15 @@ static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, 


static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)

{

	struct mem_cgroup *memcg;

	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);

	int type, name;



	memcg = mem_cgroup_from_cont(cont);

	type = MEMFILE_TYPE(event);

	name = MEMFILE_ATTR(event);



	if (!do_swap_account && type == _MEMSWAP)

		return -EOPNOTSUPP;



	switch (name) {

	case RES_MAX_USAGE:

		if (type == _MEM)
@@ -4655,7 +4671,7 @@ static struct cftype mem_cgroup_files[] = { 
	{

		.name = "usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

		.register_event = mem_cgroup_usage_register_event,

		.unregister_event = mem_cgroup_usage_unregister_event,

	},
@@ -4663,25 +4679,25 @@ static struct cftype mem_cgroup_files[] = { 
		.name = "max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

	{

		.name = "limit_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),

		.write_string = mem_cgroup_write,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

	{

		.name = "soft_limit_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),

		.write_string = mem_cgroup_write,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

	{

		.name = "failcnt",

		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

	{

		.name = "stat",
@@ -4721,14 +4737,11 @@ static struct cftype mem_cgroup_files[] = { 
		.mode = S_IRUGO,

	},

#endif

};



#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP

static struct cftype memsw_cgroup_files[] = {

	{

		.name = "memsw.usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

		.register_event = mem_cgroup_usage_register_event,

		.unregister_event = mem_cgroup_usage_unregister_event,

	},
@@ -4736,35 +4749,22 @@ static struct cftype memsw_cgroup_files[] = { 
		.name = "memsw.max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

	{

		.name = "memsw.limit_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),

		.write_string = mem_cgroup_write,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

	{

		.name = "memsw.failcnt",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.read_u64 = mem_cgroup_read,

		.read = mem_cgroup_read,

	},

};



static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)

{

	if (!do_swap_account)

		return 0;

	return cgroup_add_files(cont, ss, memsw_cgroup_files,

				ARRAY_SIZE(memsw_cgroup_files));

};

#else

static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)

{

	return 0;

}

#endif

};



static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)

{
@@ -5046,9 +5046,6 @@ static int mem_cgroup_populate(struct cgroup_subsys *ss, 
	ret = cgroup_add_files(cont, ss, mem_cgroup_files,

				ARRAY_SIZE(mem_cgroup_files));



	if (!ret)

		ret = register_memsw_files(cont, ss);



	if (!ret)

		ret = register_kmem_files(cont, ss);