Commit 8202acc6 authored by zhaoxiaoqiang11's avatar zhaoxiaoqiang11
Browse files

memcg/swap: add ability to disable memcg swap 

jingdong inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8AQ5E



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

in cloud native environment, we need to disable container swap
and enable it only in special cases.

Usage:
echo 2 > /proc/sys/vm/memcg_swap_qos_enable to enable this new feature.

Note:
some write operation will be invalid

Valid change:
0 => 1 (enable swap qos, SWAP_TYPE_ALL)
0 => 2 (enable swap qos, SWAP_TYPE_NONE)
1 => 0 (disable swap qos)
2 => 0 (disable swap qos)

Invalid change:
1 => 2 (SWAP_TYPE_ALL => SWAP_TYPE_NONE)
2 => 1 (SWAP_TYPE_NONE => SWAP_TYPE_ALL)
and write operation will return -EINVAL

Signed-off-by: default avatarzhaoxiaoqiang11 <zhaoxiaoqiang11@jd.com>
Reviewed-by: default avatarzhangwei123171 <zhangwei123171@jd.com>
parent 3e491e57

include/linux/memcontrol.h

+5 −0
Original line number Diff line number Diff line
@@ -437,6 +437,11 @@ void memcg_print_bad_task(struct oom_control *oc); 


#ifdef CONFIG_MEMCG_SWAP_QOS

DECLARE_STATIC_KEY_FALSE(memcg_swap_qos_key);



#define MEMCG_SWAP_STAT_DISABLE		0

#define MEMCG_SWAP_STAT_ALL		1

#define MEMCG_SWAP_STAT_NONE		2

#define MAX_MEMCG_SWAP_TYPE		MEMCG_SWAP_STAT_NONE

#endif



/*

mm/memcontrol.c

+28 −9
Original line number Diff line number Diff line
@@ -4064,14 +4064,15 @@ DEFINE_STATIC_KEY_FALSE(memcg_swap_qos_key); 


#ifdef CONFIG_SYSCTL

static int sysctl_memcg_swap_qos_stat;

static int swap_qos_type_max = MAX_MEMCG_SWAP_TYPE;



static void memcg_swap_qos_reset(void)

static void memcg_swap_qos_reset(int type)

{

	struct mem_cgroup *memcg;



	for_each_mem_cgroup(memcg) {

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

		WRITE_ONCE(memcg->swap_dev->type, SWAP_TYPE_ALL);

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

	}

}
@@ -4079,21 +4080,39 @@ static int sysctl_memcg_swap_qos_handler(struct ctl_table *table, int write, 
			void __user *buffer, size_t *length, loff_t *ppos)

{

	int ret;

	int qos_stat_old = sysctl_memcg_swap_qos_stat;

	int swap_type;



	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);

	if (ret)

		return ret;



	if (qos_stat_old == sysctl_memcg_swap_qos_stat)

		return 0;



	if (write) {

		if (sysctl_memcg_swap_qos_stat &&

				!static_branch_likely(&memcg_swap_qos_key)) {

			memcg_swap_qos_reset();



		switch (sysctl_memcg_swap_qos_stat) {

		case MEMCG_SWAP_STAT_DISABLE:

			static_branch_disable(&memcg_swap_qos_key);

			return 0;

		case MEMCG_SWAP_STAT_ALL:

			swap_type = SWAP_TYPE_ALL;

			break;

		case MEMCG_SWAP_STAT_NONE:

			swap_type = SWAP_TYPE_NONE;

			break;

		}



		if (!qos_stat_old) {

			memcg_swap_qos_reset(swap_type);

			static_branch_enable(&memcg_swap_qos_key);

			enable_swap_slots_cache_max();

		} else if (!sysctl_memcg_swap_qos_stat &&

				static_branch_likely(&memcg_swap_qos_key)) {

			static_branch_disable(&memcg_swap_qos_key);

		} else {

			return -EINVAL;

		}

	}



	return 0;

}
@@ -4105,7 +4124,7 @@ static struct ctl_table memcg_swap_qos_sysctls[] = { 
		.mode		= 0644,

		.proc_handler	= sysctl_memcg_swap_qos_handler,

		.extra1		= SYSCTL_ZERO,

		.extra2		= SYSCTL_ONE,

		.extra2		= &swap_qos_type_max,

	},

	{ }

};