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Date: Wed, 19 May 2010 20:58:59 +0200
From: Thomas Renninger <trenn@...e.de>
To: trenn@...e.de, peterz@...radead.org
Cc: mike@...roid.com, linux-kernel@...r.kernel.org,
lizf@...fujitsu.com, menage@...gle.com,
containers@...ts.linux-foundation.org, mingo@...e.hu
Subject: [PATCH 2/2] scheduler: cgroups cpuaccouting: Make cpuusage atomic
and avoid locking on 32 bit.
This resolves an ugly dependency in cgroups_cpuaccount.c
to per_cpu runqueues lock variable.
Signed-off-by: Thomas Renninger <trenn@...e.de>
CC: linux-kernel@...r.kernel.org
CC: mike@...roid.com
CC: menage@...gle.com
CC: lizf@...fujitsu.com
CC: containers@...ts.linux-foundation.org
CC: mingo@...e.hu
CC: peterz@...radead.org
---
kernel/cgroup_cpuaccount.c | 39 +++++++++------------------------------
kernel/sched.c | 11 -----------
kernel/sched.h | 7 -------
3 files changed, 9 insertions(+), 48 deletions(-)
delete mode 100644 kernel/sched.h
diff --git a/kernel/cgroup_cpuaccount.c b/kernel/cgroup_cpuaccount.c
index 0ad356a..0a53487 100644
--- a/kernel/cgroup_cpuaccount.c
+++ b/kernel/cgroup_cpuaccount.c
@@ -10,8 +10,6 @@
#include <asm/cputime.h>
-#include "sched.h"
-
/*
* CPU accounting code for task groups.
*
@@ -23,7 +21,7 @@
struct cpuacct {
struct cgroup_subsys_state css;
/* cpuusage holds pointer to a u64-type object on every cpu */
- u64 __percpu *cpuusage;
+ atomic64_t __percpu *cpuusage;
struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
struct cpuacct *parent;
};
@@ -54,7 +52,7 @@ static struct cgroup_subsys_state *cpuacct_create(
if (!ca)
goto out;
- ca->cpuusage = alloc_percpu(u64);
+ ca->cpuusage = alloc_percpu(atomic64_t);
if (!ca->cpuusage)
goto out_free_ca;
@@ -92,37 +90,18 @@ cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
{
- u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+ atomic64_t *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
u64 data;
-#ifndef CONFIG_64BIT
- /*
- * Take rq->lock to make 64-bit read safe on 32-bit platforms.
- */
- lock_runqueue(cpu);
- data = *cpuusage;
- unlock_runqueue(cpu);
-#else
- data = *cpuusage;
-#endif
-
+ data = atomic64_read(cpuusage);
return data;
}
static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
{
- u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
-
-#ifndef CONFIG_64BIT
- /*
- * Take rq->lock to make 64-bit write safe on 32-bit platforms.
- */
- lock_runqueue(cpu);
- *cpuusage = val;
- unlock_runqueue(cpu);
-#else
- *cpuusage = val;
-#endif
+ atomic64_t *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+
+ atomic64_set(cpuusage, val);
}
/* return total cpu usage (in nanoseconds) of a group */
@@ -232,8 +211,8 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime)
ca = task_ca(tsk);
for (; ca; ca = ca->parent) {
- u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
- *cpuusage += cputime;
+ atomic64_t *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+ atomic64_add(cputime, cpuusage);
}
rcu_read_unlock();
diff --git a/kernel/sched.c b/kernel/sched.c
index fc93cbd..e1caba2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -78,7 +78,6 @@
#include <asm/irq_regs.h>
#include "sched_cpupri.h"
-#include "sched.h"
#define CREATE_TRACE_POINTS
#include <trace/events/sched.h>
@@ -642,16 +641,6 @@ static inline int cpu_of(struct rq *rq)
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
#define raw_rq() (&__raw_get_cpu_var(runqueues))
-void lock_runqueue(unsigned int cpu)
-{
- raw_spin_lock_irq(&cpu_rq(cpu)->lock);
-}
-
-void unlock_runqueue(unsigned int cpu)
-{
- raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
-}
-
inline void update_rq_clock(struct rq *rq)
{
if (!rq->skip_clock_update)
diff --git a/kernel/sched.h b/kernel/sched.h
deleted file mode 100644
index 2fc20e0..0000000
--- a/kernel/sched.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#ifndef _LINUX_SCHED_LOCAL_H
-#define _LINUX_SCHED_LOCAL_H
-
-void lock_runqueue(unsigned int cpu);
-void unlock_runqueue(unsigned int cpu);
-
-#endif
--
1.6.3
--
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