From: Leonardo Bras <leobras@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Joel Fernandes <joel@joelfernandes.org>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun.feng@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Cc: Leonardo Bras <leobras@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
rcu@vger.kernel.org
Subject: [RFC PATCH v1 1/2] kvm: Implement guest_exit_last_time()
Date: Thu, 28 Mar 2024 14:19:46 -0300 [thread overview]
Message-ID: <20240328171949.743211-2-leobras@redhat.com> (raw)
In-Reply-To: <20240328171949.743211-1-leobras@redhat.com>
Keep track of the last time a cpu ran guest_exit(), and provide a helper to
make this information available to other files.
Signed-off-by: Leonardo Bras <leobras@redhat.com>
---
include/linux/kvm_host.h | 13 +++++++++++++
virt/kvm/kvm_main.c | 3 +++
2 files changed, 16 insertions(+)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 48f31dcd318a..be90d83d631a 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -470,31 +470,44 @@ static __always_inline void guest_state_enter_irqoff(void)
{
instrumentation_begin();
trace_hardirqs_on_prepare();
lockdep_hardirqs_on_prepare();
instrumentation_end();
guest_context_enter_irqoff();
lockdep_hardirqs_on(CALLER_ADDR0);
}
+DECLARE_PER_CPU(unsigned long, kvm_last_guest_exit);
+
+/*
+ * Returns time (jiffies) for the last guest exit in current cpu
+ */
+static inline unsigned long guest_exit_last_time(void)
+{
+ return this_cpu_read(kvm_last_guest_exit);
+}
+
/*
* Exit guest context and exit an RCU extended quiescent state.
*
* Between guest_context_enter_irqoff() and guest_context_exit_irqoff() it is
* unsafe to use any code which may directly or indirectly use RCU, tracing
* (including IRQ flag tracing), or lockdep. All code in this period must be
* non-instrumentable.
*/
static __always_inline void guest_context_exit_irqoff(void)
{
context_tracking_guest_exit();
+
+ /* Keeps track of last guest exit */
+ this_cpu_write(kvm_last_guest_exit, jiffies);
}
/*
* Stop accounting time towards a guest.
* Must be called after exiting guest context.
*/
static __always_inline void guest_timing_exit_irqoff(void)
{
instrumentation_begin();
/* Flush the guest cputime we spent on the guest */
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index fb49c2a60200..732b1ab43ac9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -103,20 +103,23 @@ EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
*/
DEFINE_MUTEX(kvm_lock);
LIST_HEAD(vm_list);
static struct kmem_cache *kvm_vcpu_cache;
static __read_mostly struct preempt_ops kvm_preempt_ops;
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
+DEFINE_PER_CPU(unsigned long, kvm_last_guest_exit);
+EXPORT_SYMBOL_GPL(kvm_last_guest_exit);
+
struct dentry *kvm_debugfs_dir;
EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
static const struct file_operations stat_fops_per_vm;
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
--
2.44.0
next prev parent reply other threads:[~2024-03-28 17:20 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-28 17:19 [RFC PATCH v1 0/2] Avoid rcu_core() if CPU just left guest vcpu Leonardo Bras
2024-03-28 17:19 ` Leonardo Bras [this message]
2024-03-28 17:19 ` [RFC PATCH v1 2/2] rcu: Ignore RCU in nohz_full cpus if it was running a guest recently Leonardo Bras
2024-04-01 15:52 ` Paul E. McKenney
2024-04-01 20:21 ` [RFC PATCH v1 0/2] Avoid rcu_core() if CPU just left guest vcpu Sean Christopherson
2024-04-05 13:45 ` Marcelo Tosatti
2024-04-05 14:42 ` Sean Christopherson
2024-04-06 0:03 ` Paul E. McKenney
2024-04-08 17:16 ` Sean Christopherson
2024-04-08 18:42 ` Paul E. McKenney
2024-04-08 20:06 ` Sean Christopherson
2024-04-08 21:02 ` Paul E. McKenney
2024-04-08 21:56 ` Sean Christopherson
2024-04-08 22:35 ` Paul E. McKenney
2024-04-08 23:06 ` Sean Christopherson
2024-04-08 23:20 ` Paul E. McKenney
2024-04-10 2:39 ` Marcelo Tosatti
2024-04-15 19:47 ` Marcelo Tosatti
2024-04-15 21:29 ` Sean Christopherson
2024-04-16 12:36 ` Marcelo Tosatti
2024-04-16 14:07 ` Sean Christopherson
2024-04-17 16:14 ` Marcelo Tosatti
2024-04-17 17:22 ` Sean Christopherson
2024-05-03 20:44 ` Leonardo Bras
2024-05-06 18:47 ` Marcelo Tosatti
2024-05-07 18:05 ` Sean Christopherson
2024-05-07 22:36 ` Leonardo Bras
2024-05-03 18:42 ` Leonardo Bras
2024-05-03 19:09 ` Leonardo Bras
2024-05-03 21:29 ` Sean Christopherson
2024-05-03 22:00 ` Leonardo Bras
2024-05-03 22:00 ` Paul E. McKenney
2024-05-07 17:55 ` Sean Christopherson
2024-05-07 19:15 ` Paul E. McKenney
2024-05-07 21:00 ` Sean Christopherson
2024-05-07 21:37 ` Paul E. McKenney
2024-05-07 23:47 ` Sean Christopherson
2024-05-08 0:08 ` Sean Christopherson
2024-05-08 2:51 ` Leonardo Bras
2024-05-08 3:22 ` Paul E. McKenney
2024-05-08 6:19 ` Leonardo Bras
2024-05-08 14:01 ` Sean Christopherson
2024-05-09 3:32 ` Paul E. McKenney
2024-05-09 8:16 ` Leonardo Bras
2024-05-09 10:14 ` Leonardo Bras
2024-05-09 23:45 ` Paul E. McKenney
2024-05-10 16:06 ` Leonardo Bras
2024-05-10 16:21 ` Paul E. McKenney
2024-05-10 17:12 ` Leonardo Bras
2024-05-10 17:41 ` Paul E. McKenney
2024-05-10 19:50 ` Leonardo Bras
2024-05-10 21:15 ` Leonardo Bras
2024-05-10 21:38 ` Paul E. McKenney
2024-05-09 22:41 ` Paul E. McKenney
2024-05-09 23:07 ` Leonardo Bras Soares Passos
2024-05-11 2:08 ` Leonardo Bras
2024-05-08 3:20 ` Paul E. McKenney
2024-05-08 4:04 ` Paul E. McKenney
2024-05-08 14:36 ` Paul E. McKenney
2024-05-08 15:35 ` Sean Christopherson
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