diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-09 15:24:03 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-09 15:24:03 -0800 |
commit | 8308756f45a12e2ff4f7749c2694fc83cdef0be9 (patch) | |
tree | 618c8f955d22927ebe73d94305d19b37c6ab65c9 /Documentation | |
parent | 23e8fe2e16587494268510c1bc9f6952f50f0311 (diff) | |
parent | afffc6c1805d98e08e778cddb644a666e78cfcfd (diff) |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core locking updates from Ingo Molnar:
"The main changes are:
- mutex, completions and rtmutex micro-optimizations
- lock debugging fix
- various cleanups in the MCS and the futex code"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Optimize setting task running after being blocked
locking/rwsem: Use task->state helpers
sched/completion: Add lock-free checking of the blocking case
sched/completion: Remove unnecessary ->wait.lock serialization when reading completion state
locking/mutex: Explicitly mark task as running after wakeup
futex: Fix argument handling in futex_lock_pi() calls
doc: Fix misnamed FUTEX_CMP_REQUEUE_PI op constants
locking/Documentation: Update code path
softirq/preempt: Add missing current->preempt_disable_ip update
locking/osq: No need for load/acquire when acquire-polling
locking/mcs: Better differentiate between MCS variants
locking/mutex: Introduce ww_mutex_set_context_slowpath()
locking/mutex: Move MCS related comments to proper location
locking/mutex: Checking the stamp is WW only
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/futex-requeue-pi.txt | 8 | ||||
-rw-r--r-- | Documentation/locking/lockdep-design.txt | 2 |
2 files changed, 5 insertions, 5 deletions
diff --git a/Documentation/futex-requeue-pi.txt b/Documentation/futex-requeue-pi.txt index 31b16610c416..77b36f59d16b 100644 --- a/Documentation/futex-requeue-pi.txt +++ b/Documentation/futex-requeue-pi.txt @@ -98,7 +98,7 @@ rt_mutex_start_proxy_lock() and rt_mutex_finish_proxy_lock(), which allow the requeue code to acquire an uncontended rt_mutex on behalf of the waiter and to enqueue the waiter on a contended rt_mutex. Two new system calls provide the kernel<->user interface to -requeue_pi: FUTEX_WAIT_REQUEUE_PI and FUTEX_REQUEUE_CMP_PI. +requeue_pi: FUTEX_WAIT_REQUEUE_PI and FUTEX_CMP_REQUEUE_PI. FUTEX_WAIT_REQUEUE_PI is called by the waiter (pthread_cond_wait() and pthread_cond_timedwait()) to block on the initial futex and wait @@ -107,7 +107,7 @@ result of a high-speed collision between futex_wait() and futex_lock_pi(), with some extra logic to check for the additional wake-up scenarios. -FUTEX_REQUEUE_CMP_PI is called by the waker +FUTEX_CMP_REQUEUE_PI is called by the waker (pthread_cond_broadcast() and pthread_cond_signal()) to requeue and possibly wake the waiting tasks. Internally, this system call is still handled by futex_requeue (by passing requeue_pi=1). Before @@ -120,12 +120,12 @@ task as a waiter on the underlying rt_mutex. It is possible that the lock can be acquired at this stage as well, if so, the next waiter is woken to finish the acquisition of the lock. -FUTEX_REQUEUE_PI accepts nr_wake and nr_requeue as arguments, but +FUTEX_CMP_REQUEUE_PI accepts nr_wake and nr_requeue as arguments, but their sum is all that really matters. futex_requeue() will wake or requeue up to nr_wake + nr_requeue tasks. It will wake only as many tasks as it can acquire the lock for, which in the majority of cases should be 0 as good programming practice dictates that the caller of either pthread_cond_broadcast() or pthread_cond_signal() acquire the -mutex prior to making the call. FUTEX_REQUEUE_PI requires that +mutex prior to making the call. FUTEX_CMP_REQUEUE_PI requires that nr_wake=1. nr_requeue should be INT_MAX for broadcast and 0 for signal. diff --git a/Documentation/locking/lockdep-design.txt b/Documentation/locking/lockdep-design.txt index 5dbc99c04f6e..5001280e9d82 100644 --- a/Documentation/locking/lockdep-design.txt +++ b/Documentation/locking/lockdep-design.txt @@ -34,7 +34,7 @@ The validator tracks lock-class usage history into 4n + 1 separate state bits: - 'ever held with STATE enabled' - 'ever held as readlock with STATE enabled' -Where STATE can be either one of (kernel/lockdep_states.h) +Where STATE can be either one of (kernel/locking/lockdep_states.h) - hardirq - softirq - reclaim_fs |