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Message-ID: <20060928173202.GG8746@in.ibm.com>
Date: Thu, 28 Sep 2006 23:02:02 +0530
From: Srivatsa Vaddagiri <vatsa@...ibm.com>
To: Ingo Molnar <mingo@...e.hu>, Nick Piggin <nickpiggin@...oo.com.au>
Cc: linux-kernel@...r.kernel.org, Kirill Korotaev <dev@...nvz.org>,
Mike Galbraith <efault@....de>,
Balbir Singh <balbir@...ibm.com>, sekharan@...ibm.com,
Andrew Morton <akpm@...l.org>, nagar@...son.ibm.com,
matthltc@...ibm.com, dipankar@...ibm.com,
ckrm-tech@...ts.sourceforge.net
Subject: [RFC, PATCH 6/9] CPU Controller V2 - Handle dont care groups
Deal with task-groups whose bandwidth hasnt been explicitly set by the
administrator. Unallocated CPU bandwidth is equally distributed among such
"don't care" groups.
Signed-off-by : Srivatsa Vaddagiri <vatsa@...ibm.com>
---
linux-2.6.18-root/include/linux/sched.h | 2
linux-2.6.18-root/kernel/sched.c | 92 ++++++++++++++++++++++++++++++--
2 files changed, 88 insertions(+), 6 deletions(-)
diff -puN kernel/sched.c~cpu_ctlr_handle_dont_cares kernel/sched.c
--- linux-2.6.18/kernel/sched.c~cpu_ctlr_handle_dont_cares 2006-09-28 16:40:28.772666712 +0530
+++ linux-2.6.18-root/kernel/sched.c 2006-09-28 17:23:16.989238448 +0530
@@ -226,6 +226,12 @@ static DEFINE_PER_CPU(struct task_grp_rq
/* task-group object - maintains information about each task-group */
struct task_grp {
unsigned short ticks, long_ticks; /* bandwidth given to task-group */
+ int left_over_pct;
+ int total_dont_care_grps;
+ int dont_care; /* Does this group care for its bandwidth ? */
+ struct task_grp *parent;
+ struct list_head dont_care_list;
+ struct list_head list;
struct task_grp_rq *rq[NR_CPUS]; /* runqueue pointer for every cpu */
};
@@ -7031,6 +7037,12 @@ void __init sched_init(void)
init_task_grp.ticks = CPU_CONTROL_SHORT_WINDOW; /* 100% bandwidth */
init_task_grp.long_ticks = NUM_LONG_TICKS;
+ init_task_grp.left_over_pct = 100; /* 100% unallocated bandwidth */
+ init_task_grp.parent = NULL;
+ init_task_grp.total_dont_care_grps = 1; /* init_task_grp itself */
+ init_task_grp.dont_care = 1;
+ INIT_LIST_HEAD(&init_task_grp.dont_care_list);
+ list_add_tail(&init_task_grp.list, &init_task_grp.dont_care_list);
for_each_possible_cpu(i) {
struct rq *rq;
@@ -7195,8 +7207,31 @@ void set_curr_task(int cpu, struct task_
#ifdef CONFIG_CPUMETER
+/* Distribute left over bandwidth equally to all "dont care" task groups */
+static void recalc_dontcare(struct task_grp *tg_root)
+{
+ int ticks;
+ struct list_head *entry;
+
+ if (!tg_root->total_dont_care_grps)
+ return;
+
+ ticks = ((tg_root->left_over_pct / tg_root->total_dont_care_grps) *
+ CPU_CONTROL_SHORT_WINDOW) / 100;
+
+ list_for_each(entry, &tg_root->dont_care_list) {
+ struct task_grp *tg;
+ int i;
+
+ tg = list_entry(entry, struct task_grp, list);
+ tg->ticks = ticks;
+ for_each_possible_cpu(i)
+ tg->rq[i]->ticks = tg->ticks;
+ }
+}
+
/* Allocate runqueue structures for the new task-group */
-void *sched_alloc_group(void)
+void *sched_alloc_group(struct task_grp *tg_parent)
{
struct task_grp *tg;
struct task_grp_rq *tgrq;
@@ -7208,6 +7243,10 @@ void *sched_alloc_group(void)
tg->ticks = CPU_CONTROL_SHORT_WINDOW;
tg->long_ticks = NUM_LONG_TICKS;
+ tg->parent = tg_parent;
+ tg->dont_care = 1;
+ tg->left_over_pct = 100;
+ INIT_LIST_HEAD(&tg->dont_care_list);
for_each_possible_cpu(i) {
tgrq = kzalloc(sizeof(*tgrq), GFP_KERNEL);
@@ -7217,6 +7256,15 @@ void *sched_alloc_group(void)
task_grp_rq_init(tgrq, tg);
}
+ if (tg->parent) {
+ tg->parent->total_dont_care_grps++;
+ list_add_tail(&tg->list, &tg->parent->dont_care_list);
+ recalc_dontcare(tg->parent);
+ } else {
+ tg->total_dont_care_grps = 1;
+ list_add_tail(&tg->list, &tg->dont_care_list);
+ }
+
return tg;
oom:
while (i--)
@@ -7230,6 +7278,16 @@ oom:
void sched_dealloc_group(struct task_grp *tg)
{
int i;
+ struct task_grp *tg_root = tg->parent;
+
+ if (!tg_root)
+ tg_root = tg;
+
+ if (tg->dont_care) {
+ tg_root->total_dont_care_grps--;
+ list_del(&tg->list);
+ recalc_dontcare(tg_root);
+ }
for_each_possible_cpu(i)
kfree(tg->rq[i]);
@@ -7240,12 +7298,33 @@ void sched_dealloc_group(struct task_grp
/* Assign quota to this group */
int sched_assign_quota(struct task_grp *tg, int quota)
{
- int i;
+ int i, old_quota = 0;
+ struct task_grp *tg_root = tg->parent;
+
+ if (!tg_root)
+ tg_root = tg;
+
+ if (!tg->dont_care)
+ old_quota = (tg->ticks * 100) / CPU_CONTROL_SHORT_WINDOW;
+
+ if (quota > (tg_root->left_over_pct - old_quota))
+ return -EINVAL;
+
+ if (tg->dont_care) {
+ tg->dont_care = 0;
+ tg_root->total_dont_care_grps--;
+ list_del(&tg->list);
+ }
tg->ticks = (quota * CPU_CONTROL_SHORT_WINDOW) / 100;
+ for_each_possible_cpu(i) {
+ tg->rq[i]->ticks = tg->ticks;
+ tg->rq[i]->long_ticks = tg->long_ticks;
+ }
- for_each_possible_cpu(i)
- tg->rq[i]->ticks = tg->ticks;
+ /* xxx: needs some locking */
+ tg_root->left_over_pct -= (quota - old_quota);
+ recalc_dontcare(tg_root);
return 0;
}
@@ -7258,7 +7337,10 @@ static inline int cpu_quota(struct task_
/* Return assigned quota for this group */
int sched_get_quota(struct task_grp *tg)
{
- return cpu_quota(tg);
+ if (tg->dont_care)
+ return 0;
+ else
+ return cpu_quota(tg);
}
/*
diff -puN include/linux/sched.h~cpu_ctlr_handle_dont_cares include/linux/sched.h
--- linux-2.6.18/include/linux/sched.h~cpu_ctlr_handle_dont_cares 2006-09-28 16:40:28.777665952 +0530
+++ linux-2.6.18-root/include/linux/sched.h 2006-09-28 16:40:28.801662304 +0530
@@ -1615,7 +1615,7 @@ static inline int try_to_freeze(void) {
#ifdef CONFIG_CPUMETER
struct task_grp;
struct task_grp_ops {
- void *(*alloc_group)(void);
+ void *(*alloc_group)(struct task_grp *grp_parent);
void (*dealloc_group)(struct task_grp *grp);
int (*assign_quota)(struct task_grp *grp, int quota);
int (*pre_move_task)(struct task_struct *tsk, unsigned long *,
_
--
Regards,
vatsa
-
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