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authorKefeng Wang <wangkefeng.wang@huawei.com>2021-12-03 15:59:34 +0800
committerPeter Zijlstra <peterz@infradead.org>2021-12-04 10:56:25 +0100
commitc0bed69daf4b67809b58cc7cd81a8fa4f45bc161 (patch)
tree2e5eac02c318c1145dace9791e1e53b74ca0dc49
parent9a75bd0c52df6cff44735f73dfb9d00e67969fc5 (diff)
locking: Make owner_on_cpu() into <linux/sched.h>
Move the owner_on_cpu() from kernel/locking/rwsem.c into include/linux/sched.h with under CONFIG_SMP, then use it in the mutex/rwsem/rtmutex to simplify the code. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211203075935.136808-2-wangkefeng.wang@huawei.com
-rw-r--r--include/linux/sched.h9
-rw-r--r--kernel/locking/mutex.c11
-rw-r--r--kernel/locking/rtmutex.c5
-rw-r--r--kernel/locking/rwsem.c9
4 files changed, 13 insertions, 21 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 78c351e35fec..ff609d9c2f21 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2171,6 +2171,15 @@ extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
#endif
#ifdef CONFIG_SMP
+static inline bool owner_on_cpu(struct task_struct *owner)
+{
+ /*
+ * As lock holder preemption issue, we both skip spinning if
+ * task is not on cpu or its cpu is preempted
+ */
+ return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
+}
+
/* Returns effective CPU energy utilization, as seen by the scheduler */
unsigned long sched_cpu_util(int cpu, unsigned long max);
#endif /* CONFIG_SMP */
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index db1913611192..5e3585950ec8 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -367,8 +367,7 @@ bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner,
/*
* Use vcpu_is_preempted to detect lock holder preemption issue.
*/
- if (!owner->on_cpu || need_resched() ||
- vcpu_is_preempted(task_cpu(owner))) {
+ if (!owner_on_cpu(owner) || need_resched()) {
ret = false;
break;
}
@@ -403,14 +402,8 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
* structure won't go away during the spinning period.
*/
owner = __mutex_owner(lock);
-
- /*
- * As lock holder preemption issue, we both skip spinning if task is not
- * on cpu or its cpu is preempted
- */
-
if (owner)
- retval = owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
+ retval = owner_on_cpu(owner);
/*
* If lock->owner is not set, the mutex has been released. Return true
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index f89620852774..0c1f2e3f019a 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1382,9 +1382,8 @@ static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock,
* for CONFIG_PREEMPT_RCU=y)
* - the VCPU on which owner runs is preempted
*/
- if (!owner->on_cpu || need_resched() ||
- rt_mutex_waiter_is_top_waiter(lock, waiter) ||
- vcpu_is_preempted(task_cpu(owner))) {
+ if (!owner_on_cpu(owner) || need_resched() ||
+ rt_mutex_waiter_is_top_waiter(lock, waiter)) {
res = false;
break;
}
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index c51387a43265..b92d0a830568 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -613,15 +613,6 @@ static inline bool rwsem_try_write_lock_unqueued(struct rw_semaphore *sem)
return false;
}
-static inline bool owner_on_cpu(struct task_struct *owner)
-{
- /*
- * As lock holder preemption issue, we both skip spinning if
- * task is not on cpu or its cpu is preempted
- */
- return owner->on_cpu && !vcpu_is_preempted(task_cpu(owner));
-}
-
static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
{
struct task_struct *owner;