diff options
Diffstat (limited to 'meta-eas/recipes-kernel/linux/linux-renesas/0082-sched-Add-group_misfit_task-load-balance-type.patch')
| -rw-r--r-- | meta-eas/recipes-kernel/linux/linux-renesas/0082-sched-Add-group_misfit_task-load-balance-type.patch | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/meta-eas/recipes-kernel/linux/linux-renesas/0082-sched-Add-group_misfit_task-load-balance-type.patch b/meta-eas/recipes-kernel/linux/linux-renesas/0082-sched-Add-group_misfit_task-load-balance-type.patch new file mode 100644 index 0000000..d020473 --- /dev/null +++ b/meta-eas/recipes-kernel/linux/linux-renesas/0082-sched-Add-group_misfit_task-load-balance-type.patch @@ -0,0 +1,141 @@ +From b58a2c49fdbb556dcc51f750f77424063d92db3c Mon Sep 17 00:00:00 2001 +From: Morten Rasmussen <morten.rasmussen@arm.com> +Date: Thu, 25 Feb 2016 12:47:54 +0000 +Subject: [PATCH 82/92] sched: Add group_misfit_task load-balance type + +To maximize throughput in systems with reduced capacity cpus (e.g. +high RT/IRQ load and/or ARM big.LITTLE) load-balancing has to consider +task and cpu utilization as well as per-cpu compute capacity when +load-balancing in addition to the current average load based +load-balancing policy. Tasks that are scheduled on a reduced capacity +cpu need to be identified and migrated to a higher capacity cpu if +possible. + +To implement this additional policy an additional group_type +(load-balance scenario) is added: group_misfit_task. This represents +scenarios where a sched_group has tasks that are not suitable for its +per-cpu capacity. group_misfit_task is only considered if the system is +not overloaded in any other way (group_imbalanced or group_overloaded). + +Identifying misfit tasks requires the rq lock to be held. To avoid +taking remote rq locks to examine source sched_groups for misfit tasks, +each cpu is responsible for tracking misfit tasks themselves and update +the rq->misfit_task flag. This means checking task utilization when +tasks are scheduled and on sched_tick. + +Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> +(cherry picked from commit a1a42660d90a077df8412b6ca763ba76506da8e6) +Signed-off-by: Gaku Inami <gaku.inami.xw@bp.renesas.com> +--- + kernel/sched/fair.c | 29 ++++++++++++++++++++++------- + kernel/sched/sched.h | 1 + + 2 files changed, 23 insertions(+), 7 deletions(-) + +diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c +index cf60d93..e7fd15e 100644 +--- a/kernel/sched/fair.c ++++ b/kernel/sched/fair.c +@@ -6627,6 +6627,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ + if (hrtick_enabled(rq)) + hrtick_start_fair(rq, p); + ++ rq->misfit_task = !task_fits_max(p, rq->cpu); ++ + return p; + simple: + cfs_rq = &rq->cfs; +@@ -6648,9 +6650,12 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ + if (hrtick_enabled(rq)) + hrtick_start_fair(rq, p); + ++ rq->misfit_task = !task_fits_max(p, rq->cpu); ++ + return p; + + idle: ++ rq->misfit_task = 0; + /* + * This is OK, because current is on_cpu, which avoids it being picked + * for load-balance and preemption/IRQs are still disabled avoiding +@@ -6863,6 +6868,13 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp + + enum fbq_type { regular, remote, all }; + ++enum group_type { ++ group_other = 0, ++ group_misfit_task, ++ group_imbalanced, ++ group_overloaded, ++}; ++ + #define LBF_ALL_PINNED 0x01 + #define LBF_NEED_BREAK 0x02 + #define LBF_DST_PINNED 0x04 +@@ -7338,12 +7350,6 @@ static unsigned long task_h_load(struct task_struct *p) + + /********** Helpers for find_busiest_group ************************/ + +-enum group_type { +- group_other = 0, +- group_imbalanced, +- group_overloaded, +-}; +- + /* + * sg_lb_stats - stats of a sched_group required for load_balancing + */ +@@ -7359,6 +7365,7 @@ struct sg_lb_stats { + unsigned int group_weight; + enum group_type group_type; + int group_no_capacity; ++ int group_misfit_task; /* A cpu has a task too big for its capacity */ + #ifdef CONFIG_NUMA_BALANCING + unsigned int nr_numa_running; + unsigned int nr_preferred_running; +@@ -7656,6 +7663,9 @@ group_type group_classify(struct sched_group *group, + if (sg_imbalanced(group)) + return group_imbalanced; + ++ if (sgs->group_misfit_task) ++ return group_misfit_task; ++ + return group_other; + } + +@@ -7707,8 +7717,11 @@ static inline void update_sg_lb_stats(struct lb_env *env, + if (!nr_running && idle_cpu(i)) + sgs->idle_cpus++; + +- if (cpu_overutilized(i)) ++ if (cpu_overutilized(i)) { + *overutilized = true; ++ if (!sgs->group_misfit_task && rq->misfit_task) ++ sgs->group_misfit_task = capacity_of(i); ++ } + } + + /* Adjust by relative CPU capacity of the group */ +@@ -9307,6 +9320,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) + + if (!rq->rd->overutilized && cpu_overutilized(task_cpu(curr))) + rq->rd->overutilized = true; ++ ++ rq->misfit_task = !task_fits_max(curr, rq->cpu); + } + + /* +diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h +index fa98ab3..704d8a4 100644 +--- a/kernel/sched/sched.h ++++ b/kernel/sched/sched.h +@@ -611,6 +611,7 @@ struct rq { + #endif + #define CPU_LOAD_IDX_MAX 5 + unsigned long cpu_load[CPU_LOAD_IDX_MAX]; ++ unsigned int misfit_task; + #ifdef CONFIG_NO_HZ_COMMON + #ifdef CONFIG_SMP + unsigned long last_load_update_tick; +-- +1.9.1 + |