On Mon, Jun 04, 2018 at 12:39:11PM -0700, Linus Torvalds wrote:
> On Mon, Jun 4, 2018 at 12:37 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> >
> > Would it help if we did s/swake_up/swake_up_one/g ?
> >
> > Then there would not be an swake_up() to cause confusion.
>
> Yes, i think that would already be a big improvement, forcing people
> to be aware of the exclusive nature.
The below will of course conflict with the merge request under
discussion. Also completely untested.
---
Subject: sched/swait: Unconfuse swake_up() vs wake_up()
Linus hates on swait because swake_up() behaves distinctly different
from wake_up(). Where the latter will wake all !exclusive waiters and a
single exclusive waiter, the former will wake but one waiter (everything
is exclusive).
To avoid easy confusion, rename swake_up() to swake_up_one():
git grep -l "\<swake_up\>" | while read file;
do
sed -ie 's/\<swake_up\>/&_one/g' $file;
done
Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/mips/kvm/mips.c | 4 ++--
arch/powerpc/kvm/book3s_hv.c | 4 ++--
arch/s390/kvm/interrupt.c | 2 +-
arch/x86/kernel/kvm.c | 2 +-
arch/x86/kvm/lapic.c | 2 +-
include/linux/swait.h | 2 +-
kernel/rcu/srcutiny.c | 2 +-
kernel/rcu/tree.c | 2 +-
kernel/rcu/tree_exp.h | 2 +-
kernel/rcu/tree_plugin.h | 6 +++---
kernel/sched/swait.c | 4 ++--
virt/kvm/arm/arm.c | 2 +-
virt/kvm/arm/psci.c | 2 +-
virt/kvm/async_pf.c | 2 +-
virt/kvm/kvm_main.c | 2 +-
15 files changed, 20 insertions(+), 20 deletions(-)
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 0f725e9cee8f..612bc713c4a1 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -515,7 +515,7 @@ int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
dvcpu->arch.wait = 0;
if (swq_has_sleeper(&dvcpu->wq))
- swake_up(&dvcpu->wq);
+ swake_up_one(&dvcpu->wq);
return 0;
}
@@ -1204,7 +1204,7 @@ static void kvm_mips_comparecount_func(unsigned long data)
vcpu->arch.wait = 0;
if (swq_has_sleeper(&vcpu->wq))
- swake_up(&vcpu->wq);
+ swake_up_one(&vcpu->wq);
}
/* low level hrtimer wake routine */
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 4d07fca5121c..f1bcf1875171 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -190,7 +190,7 @@ static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu)
wqp = kvm_arch_vcpu_wq(vcpu);
if (swq_has_sleeper(wqp)) {
- swake_up(wqp);
+ swake_up_one(wqp);
++vcpu->stat.halt_wakeup;
}
@@ -3224,7 +3224,7 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
kvmppc_start_thread(vcpu, vc);
trace_kvm_guest_enter(vcpu);
} else if (vc->vcore_state == VCORE_SLEEPING) {
- swake_up(&vc->wq);
+ swake_up_one(&vc->wq);
}
}
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 37d06e022238..f58113cbee4d 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1145,7 +1145,7 @@ void kvm_s390_vcpu_wakeup(struct kvm_vcpu *vcpu)
* yield-candidate.
*/
vcpu->preempted = true;
- swake_up(&vcpu->wq);
+ swake_up_one(&vcpu->wq);
vcpu->stat.halt_wakeup++;
}
/*
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 5b2300b818af..db6ebe48d991 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -188,7 +188,7 @@ static void apf_task_wake_one(struct kvm_task_sleep_node *n)
if (n->halted)
smp_send_reschedule(n->cpu);
else if (swq_has_sleeper(&n->wq))
- swake_up(&n->wq);
+ swake_up_one(&n->wq);
}
static void apf_task_wake_all(void)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b74c9c1405b9..a2f8c4c76d33 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1379,7 +1379,7 @@ static void apic_timer_expired(struct kvm_lapic *apic)
* using swait_active() is safe.
*/
if (swait_active(q))
- swake_up(q);
+ swake_up_one(q);
if (apic_lvtt_tscdeadline(apic))
ktimer->expired_tscdeadline = ktimer->tscdeadline;
diff --git a/include/linux/swait.h b/include/linux/swait.h
index 84f9745365ff..6224bbb08cf5 100644
--- a/include/linux/swait.h
+++ b/include/linux/swait.h
@@ -145,7 +145,7 @@ static inline bool swq_has_sleeper(struct swait_queue_head *wq)
return swait_active(wq);
}
-extern void swake_up(struct swait_queue_head *q);
+extern void swake_up_one(struct swait_queue_head *q);
extern void swake_up_all(struct swait_queue_head *q);
extern void swake_up_locked(struct swait_queue_head *q);
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index 622792abe41a..790876228824 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -110,7 +110,7 @@ void __srcu_read_unlock(struct srcu_struct *sp, int idx)
WRITE_ONCE(sp->srcu_lock_nesting[idx], newval);
if (!newval && READ_ONCE(sp->srcu_gp_waiting))
- swake_up(&sp->srcu_wq);
+ swake_up_one(&sp->srcu_wq);
}
EXPORT_SYMBOL_GPL(__srcu_read_unlock);
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 4fccdfa25716..c5fbd74c8af0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1727,7 +1727,7 @@ static void rcu_gp_kthread_wake(struct rcu_state *rsp)
!READ_ONCE(rsp->gp_flags) ||
!rsp->gp_kthread)
return;
- swake_up(&rsp->gp_wq);
+ swake_up_one(&rsp->gp_wq);
}
/*
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index d40708e8c5d6..027a432a167d 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -212,7 +212,7 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (wake) {
smp_mb(); /* EGP done before wake_up(). */
- swake_up(&rsp->expedited_wq);
+ swake_up_one(&rsp->expedited_wq);
}
break;
}
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 7fd12039e512..1245610f689d 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1854,8 +1854,8 @@ static void __wake_nocb_leader(struct rcu_data *rdp, bool force,
WRITE_ONCE(rdp_leader->nocb_leader_sleep, false);
del_timer(&rdp->nocb_timer);
raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
- smp_mb(); /* ->nocb_leader_sleep before swake_up(). */
- swake_up(&rdp_leader->nocb_wq);
+ smp_mb(); /* ->nocb_leader_sleep before swake_up_one(). */
+ swake_up_one(&rdp_leader->nocb_wq);
} else {
raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
}
@@ -2176,7 +2176,7 @@ static void nocb_leader_wait(struct rcu_data *my_rdp)
raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags);
if (rdp != my_rdp && tail == &rdp->nocb_follower_head) {
/* List was empty, so wake up the follower. */
- swake_up(&rdp->nocb_wq);
+ swake_up_one(&rdp->nocb_wq);
}
}
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index b6fb2c3b3ff7..e471a58f565c 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -32,7 +32,7 @@ void swake_up_locked(struct swait_queue_head *q)
}
EXPORT_SYMBOL(swake_up_locked);
-void swake_up(struct swait_queue_head *q)
+void swake_up_one(struct swait_queue_head *q)
{
unsigned long flags;
@@ -40,7 +40,7 @@ void swake_up(struct swait_queue_head *q)
swake_up_locked(q);
raw_spin_unlock_irqrestore(&q->lock, flags);
}
-EXPORT_SYMBOL(swake_up);
+EXPORT_SYMBOL(swake_up_one);
/*
* Does not allow usage from IRQ disabled, since we must be able to
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index a4c1b76240df..172e82b75e3f 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -586,7 +586,7 @@ void kvm_arm_resume_guest(struct kvm *kvm)
kvm_for_each_vcpu(i, vcpu, kvm) {
vcpu->arch.pause = false;
- swake_up(kvm_arch_vcpu_wq(vcpu));
+ swake_up_one(kvm_arch_vcpu_wq(vcpu));
}
}
diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
index c4762bef13c6..18effcb166ad 100644
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -155,7 +155,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
smp_mb(); /* Make sure the above is visible */
wq = kvm_arch_vcpu_wq(vcpu);
- swake_up(wq);
+ swake_up_one(wq);
return PSCI_RET_SUCCESS;
}
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 57bcb27dcf30..23c2519c5b32 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -107,7 +107,7 @@ static void async_pf_execute(struct work_struct *work)
trace_kvm_async_pf_completed(addr, gva);
if (swq_has_sleeper(&vcpu->wq))
- swake_up(&vcpu->wq);
+ swake_up_one(&vcpu->wq);
mmput(mm);
kvm_put_kvm(vcpu->kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c7b2e927f699..8cbf1276ed2e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2197,7 +2197,7 @@ bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
wqp = kvm_arch_vcpu_wq(vcpu);
if (swq_has_sleeper(wqp)) {
- swake_up(wqp);
+ swake_up_one(wqp);
++vcpu->stat.halt_wakeup;
return true;
}
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
