Add Cgroup interface for latency-nice. Each CPU Cgroup adds a new file "latency-nice" which is shared by all the threads in that Cgroup.
Signed-off-by: subhra mazumdar <subhra.mazum...@oracle.com> --- include/linux/sched.h | 1 + kernel/sched/core.c | 40 ++++++++++++++++++++++++++++++++++++++++ kernel/sched/fair.c | 1 + kernel/sched/sched.h | 8 ++++++++ 4 files changed, 50 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index 1183741..b4a79c3 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -631,6 +631,7 @@ struct task_struct { int static_prio; int normal_prio; unsigned int rt_priority; + u64 latency_nice; const struct sched_class *sched_class; struct sched_entity se; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 874c427..47969bc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5976,6 +5976,7 @@ void __init sched_init(void) init_dl_rq(&rq->dl); #ifdef CONFIG_FAIR_GROUP_SCHED root_task_group.shares = ROOT_TASK_GROUP_LOAD; + root_task_group.latency_nice = LATENCY_NICE_DEFAULT; INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; /* @@ -6345,6 +6346,7 @@ static void sched_change_group(struct task_struct *tsk, int type) */ tg = container_of(task_css_check(tsk, cpu_cgrp_id, true), struct task_group, css); + tsk->latency_nice = tg->latency_nice; tg = autogroup_task_group(tsk, tg); tsk->sched_task_group = tg; @@ -6812,6 +6814,34 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, } #endif /* CONFIG_RT_GROUP_SCHED */ +static u64 cpu_latency_nice_read_u64(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct task_group *tg = css_tg(css); + + return tg->latency_nice; +} + +static int cpu_latency_nice_write_u64(struct cgroup_subsys_state *css, + struct cftype *cft, u64 latency_nice) +{ + struct task_group *tg = css_tg(css); + struct css_task_iter it; + struct task_struct *p; + + if (latency_nice < LATENCY_NICE_MIN || latency_nice > LATENCY_NICE_MAX) + return -ERANGE; + + tg->latency_nice = latency_nice; + + css_task_iter_start(css, 0, &it); + while ((p = css_task_iter_next(&it))) + p->latency_nice = latency_nice; + css_task_iter_end(&it); + + return 0; +} + static struct cftype cpu_legacy_files[] = { #ifdef CONFIG_FAIR_GROUP_SCHED { @@ -6848,6 +6878,11 @@ static struct cftype cpu_legacy_files[] = { .write_u64 = cpu_rt_period_write_uint, }, #endif + { + .name = "latency-nice", + .read_u64 = cpu_latency_nice_read_u64, + .write_u64 = cpu_latency_nice_write_u64, + }, { } /* Terminate */ }; @@ -7015,6 +7050,11 @@ static struct cftype cpu_files[] = { .write = cpu_max_write, }, #endif + { + .name = "latency-nice", + .read_u64 = cpu_latency_nice_read_u64, + .write_u64 = cpu_latency_nice_write_u64, + }, { } /* terminate */ }; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f35930f..b08d00c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10479,6 +10479,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) goto err; tg->shares = NICE_0_LOAD; + tg->latency_nice = LATENCY_NICE_DEFAULT; init_cfs_bandwidth(tg_cfs_bandwidth(tg)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index b52ed1a..365c928 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -143,6 +143,13 @@ static inline void cpu_load_update_active(struct rq *this_rq) { } #define NICE_0_LOAD (1L << NICE_0_LOAD_SHIFT) /* + * Latency-nice default value + */ +#define LATENCY_NICE_DEFAULT 5 +#define LATENCY_NICE_MIN 1 +#define LATENCY_NICE_MAX 100 + +/* * Single value that decides SCHED_DEADLINE internal math precision. * 10 -> just above 1us * 9 -> just above 0.5us @@ -362,6 +369,7 @@ struct cfs_bandwidth { /* Task group related information */ struct task_group { struct cgroup_subsys_state css; + u64 latency_nice; #ifdef CONFIG_FAIR_GROUP_SCHED /* schedulable entities of this group on each CPU */ -- 2.9.3