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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-06-12 13:30:25 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-07-09 09:15:01 -0700
commitabaa93d9e1de2c29297e69ddba8ddd38f15064cf (patch)
tree127f64c80be6f30fed7265d42cbfc5b449853618 /include/linux/init_task.h
parentrcu: Check both root and current rcu_node when setting up future grace period (diff)
downloadwireguard-linux-abaa93d9e1de2c29297e69ddba8ddd38f15064cf.tar.xz
wireguard-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 'include/linux/init_task.h')
-rw-r--r--include/linux/init_task.h9
1 files changed, 1 insertions, 8 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 6df7f9fe0d01..2bb4c4f3531a 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -102,12 +102,6 @@ extern struct group_info init_groups;
#define INIT_IDS
#endif
-#ifdef CONFIG_RCU_BOOST
-#define INIT_TASK_RCU_BOOST() \
- .rcu_boost_mutex = NULL,
-#else
-#define INIT_TASK_RCU_BOOST()
-#endif
#ifdef CONFIG_TREE_PREEMPT_RCU
#define INIT_TASK_RCU_TREE_PREEMPT() \
.rcu_blocked_node = NULL,
@@ -119,8 +113,7 @@ extern struct group_info init_groups;
.rcu_read_lock_nesting = 0, \
.rcu_read_unlock_special = 0, \
.rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry), \
- INIT_TASK_RCU_TREE_PREEMPT() \
- INIT_TASK_RCU_BOOST()
+ INIT_TASK_RCU_TREE_PREEMPT()
#else
#define INIT_TASK_RCU_PREEMPT(tsk)
#endif