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Commit 791badbd authored by Tejun Heo's avatar Tejun Heo
Browse files

memcg: convert away from cftype->read() and ->read_map() 



In preparation of conversion to kernfs, cgroup file handling is being
consolidated so that it can be easily mapped to the seq_file based
interface of kernfs.

cftype->read_map() doesn't add any value and being replaced with
->read_seq_string(), and all users of cftype->read() can be easily
served, usually better, by seq_file and other methods.

Update mem_cgroup_read() to return u64 instead of printing itself and
rename it to mem_cgroup_read_u64(), and update
mem_cgroup_oom_control_read() to use ->read_seq_string() instead of
->read_map().

This patch doesn't make any visible behavior changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
parent 51ffe411

mm/memcontrol.c

+21 −28
Original line number Diff line number Diff line
@@ -5150,14 +5150,12 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) 
	return val << PAGE_SHIFT;

}



static ssize_t mem_cgroup_read(struct cgroup_subsys_state *css,

			       struct cftype *cft, struct file *file,

			       char __user *buf, size_t nbytes, loff_t *ppos)

static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,

				   struct cftype *cft)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);

	char str[64];

	u64 val;

	int name, len;

	int name;

	enum res_type type;



	type = MEMFILE_TYPE(cft->private);
@@ -5183,8 +5181,7 @@ static ssize_t mem_cgroup_read(struct cgroup_subsys_state *css, 
		BUG();

	}



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

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

	return val;

}



static int memcg_update_kmem_limit(struct cgroup_subsys_state *css, u64 val)
@@ -5911,16 +5908,12 @@ static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg, 
}



static int mem_cgroup_oom_control_read(struct cgroup_subsys_state *css,

	struct cftype *cft,  struct cgroup_map_cb *cb)

				       struct cftype *cft, struct seq_file *sf)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);



	cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);



	if (atomic_read(&memcg->under_oom))

		cb->fill(cb, "under_oom", 1);

	else

		cb->fill(cb, "under_oom", 0);

	seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);

	seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));

	return 0;

}
@@ -6239,31 +6232,31 @@ static struct cftype mem_cgroup_files[] = { 
	{

		.name = "usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "limit_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),

		.write_string = mem_cgroup_write,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "soft_limit_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),

		.write_string = mem_cgroup_write,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "failcnt",

		.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "stat",
@@ -6297,7 +6290,7 @@ static struct cftype mem_cgroup_files[] = { 
	},

	{

		.name = "oom_control",

		.read_map = mem_cgroup_oom_control_read,

		.read_seq_string = mem_cgroup_oom_control_read,

		.write_u64 = mem_cgroup_oom_control_write,

		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),

	},
@@ -6315,24 +6308,24 @@ static struct cftype mem_cgroup_files[] = { 
		.name = "kmem.limit_in_bytes",

		.private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),

		.write_string = mem_cgroup_write,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "kmem.usage_in_bytes",

		.private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "kmem.failcnt",

		.private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "kmem.max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

#ifdef CONFIG_SLABINFO

	{
@@ -6349,25 +6342,25 @@ static struct cftype memsw_cgroup_files[] = { 
	{

		.name = "memsw.usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "memsw.max_usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),

		.trigger = mem_cgroup_reset,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "memsw.limit_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),

		.write_string = mem_cgroup_write,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{

		.name = "memsw.failcnt",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),

		.trigger = mem_cgroup_reset,

		.read = mem_cgroup_read,

		.read_u64 = mem_cgroup_read_u64,

	},

	{ },	/* terminate */

};