| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1308850515-15242-29-git-send-email-paul.gortmaker@windriver.com>
Date: Thu, 23 Jun 2011 13:32:36 -0400
From: Paul Gortmaker <paul.gortmaker@...driver.com>
To: stable@...nel.org, linux-kernel@...r.kernel.org
Cc: stable-review@...nel.org, Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...e.hu>,
Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [34-longterm 088/247] sched: Fix wake_affine() vs RT tasks
From: Peter Zijlstra <a.p.zijlstra@...llo.nl>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------
commit e51fd5e22e12b39f49b1bb60b37b300b17378a43 upstream.
Mike reports that since e9e9250b (sched: Scale down cpu_power due to RT
tasks), wake_affine() goes funny on RT tasks due to them still having a
!0 weight and wake_affine() still subtracts that from the rq weight.
Since nobody should be using se->weight for RT tasks, set the value to
zero. Also, since we now use ->cpu_power to normalize rq weights to
account for RT cpu usage, add that factor into the imbalance computation.
Reported-by: Mike Galbraith <efault@....de>
Tested-by: Mike Galbraith <efault@....de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
LKML-Reference: <1275316109.27810.22969.camel@...ns>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
kernel/sched.c | 24 ++++++------------------
kernel/sched_fair.c | 23 +++++++++++++++++------
2 files changed, 23 insertions(+), 24 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 39456fc..7e728cf 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -541,6 +541,8 @@ struct rq {
struct root_domain *rd;
struct sched_domain *sd;
+ unsigned long cpu_power;
+
unsigned char idle_at_tick;
/* For active balancing */
int post_schedule;
@@ -1496,24 +1498,9 @@ static unsigned long target_load(int cpu, int type)
return max(rq->cpu_load[type-1], total);
}
-static struct sched_group *group_of(int cpu)
-{
- struct sched_domain *sd = rcu_dereference_sched(cpu_rq(cpu)->sd);
-
- if (!sd)
- return NULL;
-
- return sd->groups;
-}
-
static unsigned long power_of(int cpu)
{
- struct sched_group *group = group_of(cpu);
-
- if (!group)
- return SCHED_LOAD_SCALE;
-
- return group->cpu_power;
+ return cpu_rq(cpu)->cpu_power;
}
static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
@@ -1850,8 +1837,8 @@ static void dec_nr_running(struct rq *rq)
static void set_load_weight(struct task_struct *p)
{
if (task_has_rt_policy(p)) {
- p->se.load.weight = prio_to_weight[0] * 2;
- p->se.load.inv_weight = prio_to_wmult[0] >> 1;
+ p->se.load.weight = 0;
+ p->se.load.inv_weight = WMULT_CONST;
return;
}
@@ -7793,6 +7780,7 @@ void __init sched_init(void)
#ifdef CONFIG_SMP
rq->sd = NULL;
rq->rd = NULL;
+ rq->cpu_power = SCHED_LOAD_SCALE;
rq->post_schedule = 0;
rq->active_balance = 0;
rq->next_balance = jiffies;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index f060583..85d9dd0 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1244,7 +1244,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
unsigned long this_load, load;
int idx, this_cpu, prev_cpu;
unsigned long tl_per_task;
- unsigned int imbalance;
struct task_group *tg;
unsigned long weight;
int balanced;
@@ -1284,8 +1283,6 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
tg = task_group(p);
weight = p->se.load.weight;
- imbalance = 100 + (sd->imbalance_pct - 100) / 2;
-
/*
* In low-load situations, where prev_cpu is idle and this_cpu is idle
* due to the sync cause above having dropped this_load to 0, we'll
@@ -1295,9 +1292,22 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
* Otherwise check if either cpus are near enough in load to allow this
* task to be woken on this_cpu.
*/
- balanced = !this_load ||
- 100*(this_load + effective_load(tg, this_cpu, weight, weight)) <=
- imbalance*(load + effective_load(tg, prev_cpu, 0, weight));
+ if (this_load) {
+ unsigned long this_eff_load, prev_eff_load;
+
+ this_eff_load = 100;
+ this_eff_load *= power_of(prev_cpu);
+ this_eff_load *= this_load +
+ effective_load(tg, this_cpu, weight, weight);
+
+ prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
+ prev_eff_load *= power_of(this_cpu);
+ prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
+
+ balanced = this_eff_load <= prev_eff_load;
+ } else
+ balanced = true;
+
rcu_read_unlock();
/*
@@ -2376,6 +2386,7 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
if (!power)
power = 1;
+ cpu_rq(cpu)->cpu_power = power;
sdg->cpu_power = power;
}
--
1.7.4.4
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists