diff options
| author | Davidlohr Bueso <dave@stgolabs.net> | 2015-02-01 22:16:24 -0800 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2016-08-26 20:20:24 +0200 |
| commit | 79b8b99415975bed29ac702184e9a3924c0ca8d1 (patch) | |
| tree | 66594472446e3f883571884255091622ac263d06 /kernel/rtmutex.c | |
| parent | c941b10f69f31a4fbbbaf99d8161062b65a911a0 (diff) | |
locking/rtmutex: Optimize setting task running after being blocked
We explicitly mark the task running after returning from
a __rt_mutex_slowlock() call, which does the actual sleeping
via wait-wake-trylocking. As such, this patch does two things:
(1) refactors the code so that setting current to TASK_RUNNING
is done by __rt_mutex_slowlock(), and not by the callers. The
downside to this is that it becomes a bit unclear when at what
point we block. As such I've added a comment that the task
blocks when calling __rt_mutex_slowlock() so readers can figure
out when it is running again.
(2) relaxes setting current's state through __set_current_state(),
instead of it's more expensive barrier alternative. There was no
need for the implied barrier as we're obviously not planning on
blocking.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422857784.18096.1.camel@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Stefan Guendhoer <stefan@guendhoer.com>
Diffstat (limited to 'kernel/rtmutex.c')
| -rw-r--r-- | kernel/rtmutex.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index d9ca207ce..e64a7b2af 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -744,6 +744,7 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state, set_current_state(state); } + __set_current_state(TASK_RUNNING); return ret; } @@ -800,10 +801,9 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state, ret = task_blocks_on_rt_mutex(lock, &waiter, current, detect_deadlock); if (likely(!ret)) + /* sleep on the mutex */ ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); - set_current_state(TASK_RUNNING); - if (unlikely(ret)) { remove_waiter(lock, &waiter); rt_mutex_handle_deadlock(ret, detect_deadlock, &waiter); @@ -1222,10 +1222,9 @@ int rt_mutex_finish_proxy_lock(struct rt_mutex *lock, set_current_state(TASK_INTERRUPTIBLE); + /* sleep on the mutex */ ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter); - set_current_state(TASK_RUNNING); - if (unlikely(ret)) remove_waiter(lock, waiter); |