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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-06-12 22:30:25 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-07-09 18:15:01 +0200 |
| commit | abaa93d9e1de2c29297e69ddba8ddd38f15064cf (patch) | |
| tree | 127f64c80be6f30fed7265d42cbfc5b449853618 /kernel/rcu/tree.h | |
| parent | rcu: Check both root and current rcu_node when setting up future grace period (diff) | |
| download | linux-abaa93d9e1de2c29297e69ddba8ddd38f15064cf.tar.xz linux-abaa93d9e1de2c29297e69ddba8ddd38f15064cf.zip | |
rcu: Simplify priority boosting by putting rt_mutex in rcu_node
RCU priority boosting currently checks for boosting via a pointer in
task_struct. However, this is not needed: As Oleg noted, if the
rt_mutex is placed in the rcu_node instead of on the booster's stack,
the boostee can simply check it see if it owns the lock. This commit
makes this change, shrinking task_struct by one pointer and the kernel
by thirteen lines.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 3eeb919e26a2..60fb0eaa2d16 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -177,6 +177,9 @@ struct rcu_node { /* to carry out the boosting is fully */ /* released with no future boostee accesses */ /* before that rt_mutex is re-initialized. */ + struct rt_mutex boost_mtx; + /* Used only for the priority-boosting */ + /* side effect, not as a lock. */ unsigned long boost_time; /* When to start boosting (jiffies). */ struct task_struct *boost_kthread_task; |