From d364232d409ae8f73dda1f1f9199d6bea8dfcb3c Mon Sep 17 00:00:00 2001 From: Jing Xiangfeng Date: Tue, 6 Jul 2021 16:51:04 +0800 Subject: [PATCH] memcg: Add static key for memcg priority hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I3ZN3O CVE: NA -------------------------------------- This patch adds a default-false static key to disable memcg priority feature. If you want to enable it by writing 1: echo 1 > /proc/sys/vm/memcg_qos_enable Signed-off-by: Jing Xiangfeng Reviewed-by: Liu Shixin Signed-off-by: Zheng Zengkai --- include/linux/memcontrol.h | 7 +++++ kernel/sysctl.c | 11 ++++++++ mm/memcontrol.c | 52 ++++++++++++++++++++++++++++++++++++++ mm/oom_kill.c | 7 +++-- 4 files changed, 73 insertions(+), 4 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 5440fcb38e06..d29cb949568c 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -342,9 +342,16 @@ struct mem_cgroup { }; #ifdef CONFIG_MEMCG_QOS +#define ENABLE_MEMCG_QOS 1 +#define DISABLE_MEMCG_QOS 0 +extern int sysctl_memcg_qos_stat; +DECLARE_STATIC_KEY_FALSE(memcg_qos_stat_key); + bool memcg_low_priority_scan_tasks(int (*)(struct task_struct *, void *), void *); void memcg_print_bad_task(void *arg, int ret); +extern int sysctl_memcg_qos_handler(struct ctl_table *table, + int write, void __user *buffer, size_t *length, loff_t *ppos); #endif /* diff --git a/kernel/sysctl.c b/kernel/sysctl.c index b9306d2bb426..e2729e82bf9b 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2825,6 +2825,17 @@ static struct ctl_table vm_table[] = { .mode = 0644, .proc_handler = hugetlb_overcommit_handler, }, +#endif +#ifdef CONFIG_MEMCG_QOS + { + .procname = "memcg_qos_enable", + .data = &sysctl_memcg_qos_stat, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = sysctl_memcg_qos_handler, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, #endif { .procname = "lowmem_reserve_ratio", diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e1eb2ffbd131..2bdd40397e9f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3957,10 +3957,16 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, #endif #ifdef CONFIG_MEMCG_QOS +int sysctl_memcg_qos_stat = DISABLE_MEMCG_QOS; +DEFINE_STATIC_KEY_FALSE(memcg_qos_stat_key); + static void memcg_qos_init(struct mem_cgroup *memcg) { struct mem_cgroup *parent = parent_mem_cgroup(memcg); + if (!static_branch_likely(&memcg_qos_stat_key)) + return; + if (!parent) return; @@ -3971,6 +3977,9 @@ static void memcg_qos_init(struct mem_cgroup *memcg) static s64 memcg_qos_read(struct cgroup_subsys_state *css, struct cftype *cft) { + if (!static_branch_likely(&memcg_qos_stat_key)) + return 0; + return mem_cgroup_from_css(css)->memcg_priority; } @@ -3979,6 +3988,9 @@ static int memcg_qos_write(struct cgroup_subsys_state *css, { struct mem_cgroup *memcg = mem_cgroup_from_css(css); + if (!static_branch_likely(&memcg_qos_stat_key)) + return -EACCES; + if (val >= 0) memcg->memcg_priority = 0; else @@ -4022,6 +4034,8 @@ bool memcg_low_priority_scan_tasks(int (*fn)(struct task_struct *, void *), int ret = 0; bool retry = true; + if (!static_branch_likely(&memcg_qos_stat_key)) + return false; retry: max = memcg_find_max_usage(last); if (!max) @@ -4058,6 +4072,9 @@ void memcg_print_bad_task(void *arg, int ret) { struct oom_control *oc = arg; + if (!static_branch_likely(&memcg_qos_stat_key)) + return; + if (!ret && oc->chosen) { struct mem_cgroup *memcg; @@ -4067,6 +4084,41 @@ void memcg_print_bad_task(void *arg, int ret) oc->chosen->pid, oc->chosen->comm); } } + +static void memcg_qos_reset(void) +{ + struct mem_cgroup *iter; + struct cgroup_subsys_state *css; + + rcu_read_lock(); + css_for_each_descendant_pre(css, &root_mem_cgroup->css) { + iter = mem_cgroup_from_css(css); + iter->memcg_priority = 0; + } + rcu_read_unlock(); +} + +int sysctl_memcg_qos_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos) +{ + int ret; + + ret = proc_dointvec_minmax(table, write, buffer, length, ppos); + if (ret) + return ret; + if (write) { + if (sysctl_memcg_qos_stat == ENABLE_MEMCG_QOS) { + static_branch_enable(&memcg_qos_stat_key); + pr_info("enable memcg priority.\n"); + } else { + static_branch_disable(&memcg_qos_stat_key); + memcg_qos_reset(); + pr_info("disable memcg priority.\n"); + } + } + + return ret; +} #endif #ifdef CONFIG_NUMA diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 275c2bdb20d2..41668bd37f52 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -316,6 +316,8 @@ static bool oom_next_task(struct task_struct *task, struct oom_control *oc, struct mem_cgroup *cur_memcg; struct mem_cgroup *oc_memcg; + if (!static_branch_likely(&memcg_qos_stat_key)) + return !points || points < oc->chosen_points; if (!points) return true; @@ -341,10 +343,7 @@ static bool oom_next_task(struct task_struct *task, struct oom_control *oc, static inline bool oom_next_task(struct task_struct *task, struct oom_control *oc, unsigned long points) { - if (!points || points < oc->chosen_points) - return true; - - return false; + return !points || points < oc->chosen_points; } #endif -- GitLab