From 051a1d1afa47206e23ae03f781c6795ce870e3d5 Mon Sep 17 00:00:00 2001
From: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Date: Tue, 18 Dec 2007 15:21:13 +0100
Subject: [PATCH] sched: fix crash on ia64, introduce task_current()
Some services (e.g. sched_setscheduler(), rt_mutex_setprio() and
sched_move_task()) must handle a given task differently in case it's the
'rq->curr' task on its run-queue. The task_running() interface is not
suitable for determining such tasks for platforms with one of the
following options:
#define __ARCH_WANT_UNLOCKED_CTXSW
#define __ARCH_WANT_INTERRUPTS_ON_CTXSW
Due to the fact that it makes use of 'p->oncpu == 1' as a criterion but
such a task is not necessarily 'rq->curr'.
The detailed explanation is available here:
https://lists.linux-foundation.org/pipermail/containers/2007-December/009262.html
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
kernel/sched.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index c6e551de795..5ae0d4296e7 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -508,10 +508,15 @@ EXPORT_SYMBOL_GPL(cpu_clock);
# define finish_arch_switch(prev) do { } while (0)
#endif
+static inline int task_current(struct rq *rq, struct task_struct *p)
+{
+ return rq->curr == p;
+}
+
#ifndef __ARCH_WANT_UNLOCKED_CTXSW
static inline int task_running(struct rq *rq, struct task_struct *p)
{
- return rq->curr == p;
+ return task_current(rq, p);
}
static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
@@ -540,7 +545,7 @@ static inline int task_running(struct rq *rq, struct task_struct *p)
#ifdef CONFIG_SMP
return p->oncpu;
#else
- return rq->curr == p;
+ return task_current(rq, p);
#endif
}
@@ -3334,7 +3339,7 @@ unsigned long long task_sched_runtime(struct task_struct *p)
rq = task_rq_lock(p, &flags);
ns = p->se.sum_exec_runtime;
- if (rq->curr == p) {
+ if (task_current(rq, p)) {
update_rq_clock(rq);
delta_exec = rq->clock - p->se.exec_start;
if ((s64)delta_exec > 0)
@@ -4021,7 +4026,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
oldprio = p->prio;
on_rq = p->se.on_rq;
- running = task_running(rq, p);
+ running = task_current(rq, p);
if (on_rq) {
dequeue_task(rq, p, 0);
if (running)
@@ -4332,7 +4337,7 @@ recheck:
}
update_rq_clock(rq);
on_rq = p->se.on_rq;
- running = task_running(rq, p);
+ running = task_current(rq, p);
if (on_rq) {
deactivate_task(rq, p, 0);
if (running)
@@ -7101,7 +7106,7 @@ void sched_move_task(struct task_struct *tsk)
update_rq_clock(rq);
- running = task_running(rq, tsk);
+ running = task_current(rq, tsk);
on_rq = tsk->se.on_rq;
if (on_rq) {
--
2.20.1