[3/4] kvm: Replace vcpu->swait with rcuwait

Message ID	20200324044453.15733-4-dave@stgolabs.net (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=keX+=5J=vger.kernel.org=kvm-owner@kernel.org> From: Davidlohr Bueso <dave@stgolabs.net> To: tglx@linutronix.de, pbonzini@redhat.com Cc: bigeasy@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, torvalds@linux-foundation.org, will@kernel.org, joel@joelfernandes.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, dave@stgolabs.net, Paul Mackerras <paulus@ozlabs.org>, kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org, Davidlohr Bueso <dbueso@suse.de> Subject: [PATCH 3/4] kvm: Replace vcpu->swait with rcuwait Date: Mon, 23 Mar 2020 21:44:52 -0700 Message-Id: <20200324044453.15733-4-dave@stgolabs.net> In-Reply-To: <20200324044453.15733-1-dave@stgolabs.net> References: <20200324044453.15733-1-dave@stgolabs.net> Sender: kvm-owner@vger.kernel.org Precedence: bulk
Series	kvm: Use rcuwait for vcpu blocking \| expand [-tip,0/4] kvm: Use rcuwait for vcpu blocking [1/4] rcuwait: Fix stale wake call name in comment [2/4] rcuwait: Let rcuwait_wake_up() return whether or not a task was awoken [3/4] kvm: Replace vcpu->swait with rcuwait [4/4] sched/swait: Reword some of the main description

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 71244bf87c3a..e049fcb3dffb 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -290,8 +290,7 @@ static enum hrtimer_restart kvm_mips_comparecount_wakeup(struct hrtimer *timer) kvm_mips_callbacks->queue_timer_int(vcpu); vcpu->arch.wait = 0; - if (swq_has_sleeper(&vcpu->wq)) - swake_up_one(&vcpu->wq); + rcuwait_wake_up(&vcpu->wait) return kvm_mips_count_timeout(vcpu); } @@ -517,8 +516,7 @@ int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, dvcpu->arch.wait = 0; - if (swq_has_sleeper(&dvcpu->wq)) - swake_up_one(&dvcpu->wq); + rcuwait_wake_up(&dvcpu->wait); return 0; } diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 506e4df2d730..6e5d85ba588d 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -78,7 +78,7 @@ struct kvmppc_vcore { struct kvm_vcpu *runnable_threads[MAX_SMT_THREADS]; struct list_head preempt_list; spinlock_t lock; - struct swait_queue_head wq; + struct rcuwait wait; spinlock_t stoltb_lock; /* protects stolen_tb and preempt_tb */ u64 stolen_tb; u64 preempt_tb; diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 6e8b8ffd06ad..e2b4a1e3fb7d 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -752,7 +752,7 @@ struct kvm_vcpu_arch { u8 irq_pending; /* Used by XIVE to signal pending guest irqs */ u32 last_inst; - struct swait_queue_head *wqp; + struct rcuwait *waitp; struct kvmppc_vcore *vcore; int ret; int trap; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 2cefd071b848..1a7a22122211 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -231,13 +231,11 @@ static bool kvmppc_ipi_thread(int cpu) static void kvmppc_fast_vcpu_kick_hv(struct kvm_vcpu *vcpu) { int cpu; - struct swait_queue_head *wqp; + struct rcuwait *wait; - wqp = kvm_arch_vcpu_wq(vcpu); - if (swq_has_sleeper(wqp)) { - swake_up_one(wqp); + wait = kvm_arch_vcpu_get_wait(vcpu); + if (rcuwait_wake_up(wait)) ++vcpu->stat.halt_wakeup; - } cpu = READ_ONCE(vcpu->arch.thread_cpu); if (cpu >= 0 && kvmppc_ipi_thread(cpu)) @@ -2116,7 +2114,7 @@ static struct kvmppc_vcore *kvmppc_vcore_create(struct kvm *kvm, int id) spin_lock_init(&vcore->lock); spin_lock_init(&vcore->stoltb_lock); - init_swait_queue_head(&vcore->wq); + rcuwait_init(&vcore->wait); vcore->preempt_tb = TB_NIL; vcore->lpcr = kvm->arch.lpcr; vcore->first_vcpuid = id; @@ -3779,7 +3777,6 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc) ktime_t cur, start_poll, start_wait; int do_sleep = 1; u64 block_ns; - DECLARE_SWAITQUEUE(wait); /* Poll for pending exceptions and ceded state */ cur = start_poll = ktime_get(); @@ -3807,10 +3804,7 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc) } } - prepare_to_swait_exclusive(&vc->wq, &wait, TASK_INTERRUPTIBLE); - if (kvmppc_vcore_check_block(vc)) { - finish_swait(&vc->wq, &wait); do_sleep = 0; /* If we polled, count this as a successful poll */ if (vc->halt_poll_ns) @@ -3823,8 +3817,8 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc) vc->vcore_state = VCORE_SLEEPING; trace_kvmppc_vcore_blocked(vc, 0); spin_unlock(&vc->lock); - schedule(); - finish_swait(&vc->wq, &wait); + rcuwait_wait_event(&vc->wait, + kvmppc_vcore_check_block(vc), TASK_IDLE); spin_lock(&vc->lock); vc->vcore_state = VCORE_INACTIVE; trace_kvmppc_vcore_blocked(vc, 1); @@ -3935,7 +3929,7 @@ 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_one(&vc->wq); + rcuwait_wake_up(&vc->wait); } } @@ -4274,7 +4268,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) } user_vrsave = mfspr(SPRN_VRSAVE); - vcpu->arch.wqp = &vcpu->arch.vcore->wq; + vcpu->arch.waitp = &vcpu->arch.vcore->wait; vcpu->arch.pgdir = kvm->mm->pgd; vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST; diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 302e9dccdd6d..32a0fab53fc9 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -754,7 +754,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (err) goto out_vcpu_uninit; - vcpu->arch.wqp = &vcpu->wq; + vcpu->arch.waitp = &vcpu->wait; kvmppc_create_vcpu_debugfs(vcpu, vcpu->vcpu_id); return 0; diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index e3099c642fec..a4420c26dfbc 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1815,7 +1815,7 @@ void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu) /* If the preempt notifier has already run, it also called apic_timer_expired */ if (!apic->lapic_timer.hv_timer_in_use) goto out; - WARN_ON(swait_active(&vcpu->wq)); + WARN_ON(rcu_dereference(vcpu->wait.task)); cancel_hv_timer(apic); apic_timer_expired(apic); diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index bcb9b2ac0791..93ab0ab66de5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -23,7 +23,7 @@ #include <linux/irqflags.h> #include <linux/context_tracking.h> #include <linux/irqbypass.h> -#include <linux/swait.h> +#include <linux/rcuwait.h> #include <linux/refcount.h> #include <linux/nospec.h> #include <asm/signal.h> @@ -277,7 +277,7 @@ struct kvm_vcpu { struct mutex mutex; struct kvm_run *run; - struct swait_queue_head wq; + struct rcuwait wait; struct pid __rcu *pid; int sigset_active; sigset_t sigset; @@ -952,12 +952,12 @@ static inline bool kvm_arch_has_assigned_device(struct kvm *kvm) } #endif -static inline struct swait_queue_head *kvm_arch_vcpu_wq(struct kvm_vcpu *vcpu) +static inline struct rcuwait *kvm_arch_vcpu_get_wait(struct kvm_vcpu *vcpu) { #ifdef __KVM_HAVE_ARCH_WQP - return vcpu->arch.wqp; + return vcpu->arch.waitp; #else - return &vcpu->wq; + return &vcpu->wait; #endif } diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index 0d9438e9de2a..4be71cb58691 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -593,7 +593,7 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu) if (map.emul_ptimer) soft_timer_cancel(&map.emul_ptimer->hrtimer); - if (swait_active(kvm_arch_vcpu_wq(vcpu))) + if (rcu_dereference(kvm_arch_vpu_get_wait(vcpu)) != NULL) kvm_timer_blocking(vcpu); /* diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index eda7b624eab8..98740a5b8c9b 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -579,16 +579,17 @@ void kvm_arm_resume_guest(struct kvm *kvm) kvm_for_each_vcpu(i, vcpu, kvm) { vcpu->arch.pause = false; - swake_up_one(kvm_arch_vcpu_wq(vcpu)); + rcuwait_wake_up(kvm_arch_vcpu_get_wait(vcpu)); } } static void vcpu_req_sleep(struct kvm_vcpu *vcpu) { - struct swait_queue_head *wq = kvm_arch_vcpu_wq(vcpu); + struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu); - swait_event_interruptible_exclusive(*wq, ((!vcpu->arch.power_off) && - (!vcpu->arch.pause))); + rcuwait_wait_event(*wait, + (!vcpu->arch.power_off) &&(!vcpu->arch.pause), + TASK_IDLE); if (vcpu->arch.power_off || vcpu->arch.pause) { /* Awaken to handle a signal, request we sleep again later. */ diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 15e5b037f92d..10b533f641a6 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -80,8 +80,7 @@ static void async_pf_execute(struct work_struct *work) trace_kvm_async_pf_completed(addr, cr2_or_gpa); - if (swq_has_sleeper(&vcpu->wq)) - swake_up_one(&vcpu->wq); + rcuwait_wake_up(&vcpu->wait); mmput(mm); kvm_put_kvm(vcpu->kvm); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 70f03ce0e5c1..887efb39fb1a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -343,7 +343,7 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) vcpu->kvm = kvm; vcpu->vcpu_id = id; vcpu->pid = NULL; - init_swait_queue_head(&vcpu->wq); + rcuwait_init(&vcpu->wait); kvm_async_pf_vcpu_init(vcpu); vcpu->pre_pcpu = -1; @@ -2465,9 +2465,8 @@ static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu) void kvm_vcpu_block(struct kvm_vcpu *vcpu) { ktime_t start, cur; - DECLARE_SWAITQUEUE(wait); - bool waited = false; u64 block_ns; + int block_check = -EINTR; kvm_arch_vcpu_blocking(vcpu); @@ -2491,17 +2490,9 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) } while (single_task_running() && ktime_before(cur, stop)); } - for (;;) { - prepare_to_swait_exclusive(&vcpu->wq, &wait, TASK_INTERRUPTIBLE); - - if (kvm_vcpu_check_block(vcpu) < 0) - break; - - waited = true; - schedule(); - } - - finish_swait(&vcpu->wq, &wait); + rcuwait_wait_event(&vcpu->wait, + (block_check = kvm_vcpu_check_block(vcpu)) < 0, + TASK_IDLE); cur = ktime_get(); out: kvm_arch_vcpu_unblocking(vcpu); @@ -2525,18 +2516,17 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu) } } - trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu)); + trace_kvm_vcpu_wakeup(block_ns, !block_check, vcpu_valid_wakeup(vcpu)); kvm_arch_vcpu_block_finish(vcpu); } EXPORT_SYMBOL_GPL(kvm_vcpu_block); bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu) { - struct swait_queue_head *wqp; + struct rcuwait *wait; - wqp = kvm_arch_vcpu_wq(vcpu); - if (swq_has_sleeper(wqp)) { - swake_up_one(wqp); + wait = kvm_arch_vcpu_get_wait(vcpu); + if (rcuwait_wake_up(wait)) { WRITE_ONCE(vcpu->ready, true); ++vcpu->stat.halt_wakeup; return true; @@ -2678,7 +2668,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode) continue; if (vcpu == me) continue; - if (swait_active(&vcpu->wq) && !vcpu_dy_runnable(vcpu)) + if (rcu_dereference(vcpu->wait.task) && + !vcpu_dy_runnable(vcpu)) continue; if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode && !kvm_arch_vcpu_in_kernel(vcpu))

[3/4] kvm: Replace vcpu->swait with rcuwait

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