korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-14 15:54:15 +08:00
Code Issues Packages Projects Releases Wiki Activity

rcu: Suppress lockdep false-positive ->boost_mtx complaints

Browse Source 
RCU priority boosting uses rt_mutex_init_proxy_locked() to initialize an
rt_mutex structure in locked state held by some other task.  When that
other task releases it, lockdep complains (quite accurately, but a bit
uselessly) that the other task never acquired it.  This complaint can
suppress other, more helpful, lockdep complaints, and in any case it is
a false positive.

This commit therefore switches from rt_mutex_unlock() to
rt_mutex_futex_unlock(), thereby avoiding the lockdep annotations.
Of course, if lockdep ever learns about rt_mutex_init_proxy_locked(),
addtional adjustments will be required.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2017-09-19 15:36:42 -07:00
parent b88697810d
commit 02a7c234e5
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/rcu/tree_plugin.h
View File

@ -531,7 +531,7 @@ void rcu_read_unlock_special(struct task_struct *t)
/* Unboost if we were boosted. */
if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex)
rt_mutex_unlock(&rnp->boost_mtx);
rt_mutex_futex_unlock(&rnp->boost_mtx);
/*
* If this was the last task on the expedited lists,