From: Christian Borntraeger Date: Tue, 25 Oct 2016 09:03:14 +0000 (+0200) Subject: locking/core: Remove cpu_relax_lowlatency() users X-Git-Tag: v4.10-rc1~192^2~24 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f2f09a4cee3507dba0e24b87ba2961a5c377d3a7;p=karo-tx-linux.git locking/core: Remove cpu_relax_lowlatency() users With the s390 special case of a yielding cpu_relax() implementation gone, we can now remove all users of cpu_relax_lowlatency() and replace them with cpu_relax(). Signed-off-by: Christian Borntraeger Signed-off-by: Peter Zijlstra (Intel) Cc: Catalin Marinas Cc: Heiko Carstens Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Nicholas Piggin Cc: Noam Camus Cc: Peter Zijlstra Cc: Russell King Cc: Thomas Gleixner Cc: Will Deacon Cc: linuxppc-dev@lists.ozlabs.org Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1477386195-32736-5-git-send-email-borntraeger@de.ibm.com Signed-off-by: Ingo Molnar --- diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c index 8832f8ec1583..383d13416442 100644 --- a/drivers/gpu/drm/i915/i915_gem_request.c +++ b/drivers/gpu/drm/i915/i915_gem_request.c @@ -723,7 +723,7 @@ bool __i915_spin_request(const struct drm_i915_gem_request *req, if (busywait_stop(timeout_us, cpu)) break; - cpu_relax_lowlatency(); + cpu_relax(); } while (!need_resched()); return false; diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 5dc128a8da83..5dc34653274a 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -342,7 +342,7 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net, endtime = busy_clock() + vq->busyloop_timeout; while (vhost_can_busy_poll(vq->dev, endtime) && vhost_vq_avail_empty(vq->dev, vq)) - cpu_relax_lowlatency(); + cpu_relax(); preempt_enable(); r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), out_num, in_num, NULL, NULL); @@ -533,7 +533,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk) while (vhost_can_busy_poll(&net->dev, endtime) && !sk_has_rx_data(sk) && vhost_vq_avail_empty(&net->dev, vq)) - cpu_relax_lowlatency(); + cpu_relax(); preempt_enable(); diff --git a/kernel/locking/mcs_spinlock.h b/kernel/locking/mcs_spinlock.h index c835270f0c2f..6a385aabcce7 100644 --- a/kernel/locking/mcs_spinlock.h +++ b/kernel/locking/mcs_spinlock.h @@ -28,7 +28,7 @@ struct mcs_spinlock { #define arch_mcs_spin_lock_contended(l) \ do { \ while (!(smp_load_acquire(l))) \ - cpu_relax_lowlatency(); \ + cpu_relax(); \ } while (0) #endif @@ -108,7 +108,7 @@ void mcs_spin_unlock(struct mcs_spinlock **lock, struct mcs_spinlock *node) return; /* Wait until the next pointer is set */ while (!(next = READ_ONCE(node->next))) - cpu_relax_lowlatency(); + cpu_relax(); } /* Pass lock to next waiter. */ diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 17a88e929e6a..a65e09a046ac 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -369,7 +369,7 @@ bool mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner) break; } - cpu_relax_lowlatency(); + cpu_relax(); } rcu_read_unlock(); @@ -492,7 +492,7 @@ static bool mutex_optimistic_spin(struct mutex *lock, * memory barriers as we'll eventually observe the right * values at the cost of a few extra spins. */ - cpu_relax_lowlatency(); + cpu_relax(); } if (!waiter) diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c index 05a37857ab55..4ea2710b9d6c 100644 --- a/kernel/locking/osq_lock.c +++ b/kernel/locking/osq_lock.c @@ -75,7 +75,7 @@ osq_wait_next(struct optimistic_spin_queue *lock, break; } - cpu_relax_lowlatency(); + cpu_relax(); } return next; @@ -122,7 +122,7 @@ bool osq_lock(struct optimistic_spin_queue *lock) if (need_resched()) goto unqueue; - cpu_relax_lowlatency(); + cpu_relax(); } return true; @@ -148,7 +148,7 @@ unqueue: if (smp_load_acquire(&node->locked)) return true; - cpu_relax_lowlatency(); + cpu_relax(); /* * Or we race against a concurrent unqueue()'s step-B, in which diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c index 19248ddf37ce..cc3ed0ccdfa2 100644 --- a/kernel/locking/qrwlock.c +++ b/kernel/locking/qrwlock.c @@ -54,7 +54,7 @@ static __always_inline void rspin_until_writer_unlock(struct qrwlock *lock, u32 cnts) { while ((cnts & _QW_WMASK) == _QW_LOCKED) { - cpu_relax_lowlatency(); + cpu_relax(); cnts = atomic_read_acquire(&lock->cnts); } } @@ -130,7 +130,7 @@ void queued_write_lock_slowpath(struct qrwlock *lock) (cmpxchg_relaxed(&l->wmode, 0, _QW_WAITING) == 0)) break; - cpu_relax_lowlatency(); + cpu_relax(); } /* When no more readers, set the locked flag */ @@ -141,7 +141,7 @@ void queued_write_lock_slowpath(struct qrwlock *lock) _QW_LOCKED) == _QW_WAITING)) break; - cpu_relax_lowlatency(); + cpu_relax(); } unlock: arch_spin_unlock(&lock->wait_lock); diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 2337b4bb2366..2fa2e2e64950 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -368,7 +368,7 @@ static noinline bool rwsem_spin_on_owner(struct rw_semaphore *sem) return false; } - cpu_relax_lowlatency(); + cpu_relax(); } rcu_read_unlock(); out: @@ -423,7 +423,7 @@ static bool rwsem_optimistic_spin(struct rw_semaphore *sem) * memory barriers as we'll eventually observe the right * values at the cost of a few extra spins. */ - cpu_relax_lowlatency(); + cpu_relax(); } osq_unlock(&sem->osq); done: diff --git a/lib/lockref.c b/lib/lockref.c index 5a92189ad711..c4bfcb8836cd 100644 --- a/lib/lockref.c +++ b/lib/lockref.c @@ -20,7 +20,7 @@ if (likely(old.lock_count == prev.lock_count)) { \ SUCCESS; \ } \ - cpu_relax_lowlatency(); \ + cpu_relax(); \ } \ } while (0)