11 files changed, 290 insertions, 52 deletions

diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index e84b8b68444a..ce9cc5aa2033 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -127,7 +127,7 @@ void vtime_account_user(struct task_struct *tsk)
  * Update process times based on virtual cpu times stored by entry.S
  * to the lowcore fields user_timer, system_timer & steal_clock.
  */
-void vtime_account(struct task_struct *tsk)
+void vtime_account_irq_enter(struct task_struct *tsk)
 {
         struct thread_info *ti = task_thread_info(tsk);
         u64 timer, system;
@@ -145,10 +145,10 @@ void vtime_account(struct task_struct *tsk)
 
         virt_timer_forward(system);
 }
-EXPORT_SYMBOL_GPL(vtime_account);
+EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
 
 void vtime_account_system(struct task_struct *tsk)
-__attribute__((alias("vtime_account")));
+__attribute__((alias("vtime_account_irq_enter")));
 EXPORT_SYMBOL_GPL(vtime_account_system);
 
 void __kprobes vtime_stop_cpu(void)
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 624ef3f45c8e..7105d5cbb762 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -153,7 +153,7 @@ extern void rcu_nmi_exit(void);
  */
 #define __irq_enter()                                   \
         do {                                            \
-                vtime_account_irq_enter(current);       \
+                account_irq_enter_time(current);        \
                 add_preempt_count(HARDIRQ_OFFSET);      \
                 trace_hardirq_enter();                  \
         } while (0)
@@ -169,7 +169,7 @@ extern void irq_enter(void);
 #define __irq_exit()                                    \
         do {                                            \
                 trace_hardirq_exit();                   \
-                vtime_account_irq_exit(current);        \
+                account_irq_exit_time(current);         \
                 sub_preempt_count(HARDIRQ_OFFSET);      \
         } while (0)
 
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 6d087c5f57f7..cc898b871cef 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -10,6 +10,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/user_namespace.h>
 #include <linux/securebits.h>
+#include <linux/seqlock.h>
 #include <net/net_namespace.h>
 
 #ifdef CONFIG_SMP
@@ -141,6 +142,15 @@ extern struct task_group root_task_group;
 # define INIT_PERF_EVENTS(tsk)
 #endif
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+# define INIT_VTIME(tsk)                                                \
+        .vtime_seqlock = __SEQLOCK_UNLOCKED(tsk.vtime_seqlock), \
+        .vtime_snap = 0,                                \
+        .vtime_snap_whence = VTIME_SYS,
+#else
+# define INIT_VTIME(tsk)
+#endif
+
 #define INIT_TASK_COMM "swapper"
 
 /*
@@ -210,6 +220,7 @@ extern struct task_group root_task_group;
         INIT_TRACE_RECURSION                                            \
         INIT_TASK_RCU_PREEMPT(tsk)                                      \
         INIT_CPUSET_SEQ                                                 \
+        INIT_VTIME(tsk)                                                 \
 }
 
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4fe2396401da..b7996a768eb2 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -741,7 +741,7 @@ static inline int kvm_deassign_device(struct kvm *kvm,
 }
 #endif /* CONFIG_IOMMU_API */
 
-static inline void guest_enter(void)
+static inline void __guest_enter(void)
 {
         /*
          * This is running in ioctl context so we can avoid
@@ -751,7 +751,7 @@ static inline void guest_enter(void)
         current->flags |= PF_VCPU;
 }
 
-static inline void guest_exit(void)
+static inline void __guest_exit(void)
 {
         /*
          * This is running in ioctl context so we can avoid
@@ -761,6 +761,22 @@ static inline void guest_exit(void)
         current->flags &= ~PF_VCPU;
 }
 
+#ifdef CONFIG_CONTEXT_TRACKING
+extern void guest_enter(void);
+extern void guest_exit(void);
+
+#else /* !CONFIG_CONTEXT_TRACKING */
+static inline void guest_enter(void)
+{
+        __guest_enter();
+}
+
+static inline void guest_exit(void)
+{
+        __guest_exit();
+}
+#endif /* !CONFIG_CONTEXT_TRACKING */
+
 static inline void kvm_guest_enter(void)
 {
         unsigned long flags;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a9c608b6154e..a9fa5145e1a7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1368,6 +1368,15 @@ struct task_struct {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
         struct cputime prev_cputime;
 #endif
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+        seqlock_t vtime_seqlock;
+        unsigned long long vtime_snap;
+        enum {
+                VTIME_SLEEPING = 0,
+                VTIME_USER,
+                VTIME_SYS,
+        } vtime_snap_whence;
+#endif
         unsigned long nvcsw, nivcsw; /* context switch counts */
         struct timespec start_time;             /* monotonic time */
         struct timespec real_start_time;        /* boot based time */
@@ -1792,11 +1801,13 @@ static inline void put_task_struct(struct task_struct *t)
                 __put_task_struct(t);
 }
 
-static inline cputime_t task_gtime(struct task_struct *t)
-{
-        return t->gtime;
-}
-
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+extern void task_cputime(struct task_struct *t,
+                         cputime_t *utime, cputime_t *stime);
+extern void task_cputime_scaled(struct task_struct *t,
+                                cputime_t *utimescaled, cputime_t *stimescaled);
+extern cputime_t task_gtime(struct task_struct *t);
+#else
 static inline void task_cputime(struct task_struct *t,
                                 cputime_t *utime, cputime_t *stime)
 {
@@ -1815,6 +1826,12 @@ static inline void task_cputime_scaled(struct task_struct *t,
         if (stimescaled)
                 *stimescaled = t->stimescaled;
 }
+
+static inline cputime_t task_gtime(struct task_struct *t)
+{
+        return t->gtime;
+}
+#endif
 extern void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
 extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st);
 
diff --git a/include/linux/vtime.h b/include/linux/vtime.h
index bb50c3ca0d79..71a5782d8c59 100644
--- a/include/linux/vtime.h
+++ b/include/linux/vtime.h
@@ -8,35 +8,44 @@ extern void vtime_task_switch(struct task_struct *prev);
 extern void vtime_account_system(struct task_struct *tsk);
 extern void vtime_account_idle(struct task_struct *tsk);
 extern void vtime_account_user(struct task_struct *tsk);
-extern void vtime_account(struct task_struct *tsk);
+extern void vtime_account_irq_enter(struct task_struct *tsk);
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-extern bool vtime_accounting_enabled(void);
-#else
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 static inline bool vtime_accounting_enabled(void) { return true; }
 #endif
 
 #else /* !CONFIG_VIRT_CPU_ACCOUNTING */
+
 static inline void vtime_task_switch(struct task_struct *prev) { }
 static inline void vtime_account_system(struct task_struct *tsk) { }
 static inline void vtime_account_user(struct task_struct *tsk) { }
-static inline void vtime_account(struct task_struct *tsk) { }
+static inline void vtime_account_irq_enter(struct task_struct *tsk) { }
 static inline bool vtime_accounting_enabled(void) { return false; }
 #endif
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-static inline void arch_vtime_task_switch(struct task_struct *tsk) { }
-static inline void vtime_user_enter(struct task_struct *tsk)
-{
-        vtime_account_system(tsk);
-}
+extern void arch_vtime_task_switch(struct task_struct *tsk);
+extern void vtime_account_irq_exit(struct task_struct *tsk);
+extern bool vtime_accounting_enabled(void);
+extern void vtime_user_enter(struct task_struct *tsk);
 static inline void vtime_user_exit(struct task_struct *tsk)
 {
         vtime_account_user(tsk);
 }
+extern void vtime_guest_enter(struct task_struct *tsk);
+extern void vtime_guest_exit(struct task_struct *tsk);
+extern void vtime_init_idle(struct task_struct *tsk);
 #else
+static inline void vtime_account_irq_exit(struct task_struct *tsk)
+{
+        /* On hard|softirq exit we always account to hard|softirq cputime */
+        vtime_account_system(tsk);
+}
 static inline void vtime_user_enter(struct task_struct *tsk) { }
 static inline void vtime_user_exit(struct task_struct *tsk) { }
+static inline void vtime_guest_enter(struct task_struct *tsk) { }
+static inline void vtime_guest_exit(struct task_struct *tsk) { }
+static inline void vtime_init_idle(struct task_struct *tsk) { }
 #endif
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
@@ -45,25 +54,15 @@ extern void irqtime_account_irq(struct task_struct *tsk);
 static inline void irqtime_account_irq(struct task_struct *tsk) { }
 #endif
 
-static inline void vtime_account_irq_enter(struct task_struct *tsk)
+static inline void account_irq_enter_time(struct task_struct *tsk)
 {
-        /*
-         * Hardirq can interrupt idle task anytime. So we need vtime_account()
-         * that performs the idle check in CONFIG_VIRT_CPU_ACCOUNTING.
-         * Softirq can also interrupt idle task directly if it calls
-         * local_bh_enable(). Such case probably don't exist but we never know.
-         * Ksoftirqd is not concerned because idle time is flushed on context
-         * switch. Softirqs in the end of hardirqs are also not a problem because
-         * the idle time is flushed on hardirq time already.
-         */
-        vtime_account(tsk);
+        vtime_account_irq_enter(tsk);
         irqtime_account_irq(tsk);
 }
 
-static inline void vtime_account_irq_exit(struct task_struct *tsk)
+static inline void account_irq_exit_time(struct task_struct *tsk)
 {
-        /* On hard|softirq exit we always account to hard|softirq cputime */
-        vtime_account_system(tsk);
+        vtime_account_irq_exit(tsk);
         irqtime_account_irq(tsk);
 }
 
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 9002e92e6372..74f68f4dc6c2 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -1,8 +1,9 @@
 #include <linux/context_tracking.h>
+#include <linux/kvm_host.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
 #include <linux/hardirq.h>
-
+#include <linux/export.h>
 
 DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
 #ifdef CONFIG_CONTEXT_TRACKING_FORCE
@@ -61,6 +62,24 @@ void user_exit(void)
         local_irq_restore(flags);
 }
 
+void guest_enter(void)
+{
+        if (vtime_accounting_enabled())
+                vtime_guest_enter(current);
+        else
+                __guest_enter();
+}
+EXPORT_SYMBOL_GPL(guest_enter);
+
+void guest_exit(void)
+{
+        if (vtime_accounting_enabled())
+                vtime_guest_exit(current);
+        else
+                __guest_exit();
+}
+EXPORT_SYMBOL_GPL(guest_exit);
+
 void context_tracking_task_switch(struct task_struct *prev,
                              struct task_struct *next)
 {
diff --git a/kernel/fork.c b/kernel/fork.c
index 65ca6d27f24e..e68a95b4cf26 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1233,6 +1233,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
         p->prev_cputime.utime = p->prev_cputime.stime = 0;
 #endif
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+        seqlock_init(&p->vtime_seqlock);
+        p->vtime_snap = 0;
+        p->vtime_snap_whence = VTIME_SLEEPING;
+#endif
+
 #if defined(SPLIT_RSS_COUNTING)
         memset(&p->rss_stat, 0, sizeof(p->rss_stat));
 #endif
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 257002c13bb0..261022d7e79d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4666,6 +4666,7 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
          */
         idle->sched_class = &idle_sched_class;
         ftrace_graph_init_idle_task(idle, cpu);
+        vtime_init_idle(idle);
 #if defined(CONFIG_SMP)
         sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
 #endif
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index a44ecdf809a1..082e05d915b4 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -492,7 +492,7 @@ void vtime_task_switch(struct task_struct *prev)
  * vtime_account().
  */
 #ifndef __ARCH_HAS_VTIME_ACCOUNT
-void vtime_account(struct task_struct *tsk)
+void vtime_account_irq_enter(struct task_struct *tsk)
 {
         if (!vtime_accounting_enabled())
                 return;
@@ -516,7 +516,7 @@ void vtime_account(struct task_struct *tsk)
         }
         vtime_account_system(tsk);
 }
-EXPORT_SYMBOL_GPL(vtime_account);
+EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
 #endif /* __ARCH_HAS_VTIME_ACCOUNT */
 
 #else /* !CONFIG_VIRT_CPU_ACCOUNTING */
@@ -600,28 +600,55 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime
 #endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
 
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-static DEFINE_PER_CPU(unsigned long long, cputime_snap);
+static unsigned long long vtime_delta(struct task_struct *tsk)
+{
+        unsigned long long clock;
+
+        clock = sched_clock();
+        if (clock < tsk->vtime_snap)
+                return 0;
 
-static cputime_t get_vtime_delta(void)
+        return clock - tsk->vtime_snap;
+}
+
+static cputime_t get_vtime_delta(struct task_struct *tsk)
 {
-        unsigned long long delta;
+        unsigned long long delta = vtime_delta(tsk);
 
-        delta = sched_clock() - __this_cpu_read(cputime_snap);
-        __this_cpu_add(cputime_snap, delta);
+        WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_SLEEPING);
+        tsk->vtime_snap += delta;
 
         /* CHECKME: always safe to convert nsecs to cputime? */
         return nsecs_to_cputime(delta);
 }
 
+static void __vtime_account_system(struct task_struct *tsk)
+{
+        cputime_t delta_cpu = get_vtime_delta(tsk);
+
+        account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
+}
+
 void vtime_account_system(struct task_struct *tsk)
 {
-        cputime_t delta_cpu;
+        if (!vtime_accounting_enabled())
+                return;
+
+        write_seqlock(&tsk->vtime_seqlock);
+        __vtime_account_system(tsk);
+        write_sequnlock(&tsk->vtime_seqlock);
+}
 
+void vtime_account_irq_exit(struct task_struct *tsk)
+{
         if (!vtime_accounting_enabled())
                 return;
 
-        delta_cpu = get_vtime_delta();
-        account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
+        write_seqlock(&tsk->vtime_seqlock);
+        if (context_tracking_in_user())
+                tsk->vtime_snap_whence = VTIME_USER;
+        __vtime_account_system(tsk);
+        write_sequnlock(&tsk->vtime_seqlock);
 }
 
 void vtime_account_user(struct task_struct *tsk)
@@ -631,14 +658,44 @@ void vtime_account_user(struct task_struct *tsk)
         if (!vtime_accounting_enabled())
                 return;
 
-        delta_cpu = get_vtime_delta();
+        delta_cpu = get_vtime_delta(tsk);
 
+        write_seqlock(&tsk->vtime_seqlock);
+        tsk->vtime_snap_whence = VTIME_SYS;
         account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
+        write_sequnlock(&tsk->vtime_seqlock);
+}
+
+void vtime_user_enter(struct task_struct *tsk)
+{
+        if (!vtime_accounting_enabled())
+                return;
+
+        write_seqlock(&tsk->vtime_seqlock);
+        tsk->vtime_snap_whence = VTIME_USER;
+        __vtime_account_system(tsk);
+        write_sequnlock(&tsk->vtime_seqlock);
+}
+
+void vtime_guest_enter(struct task_struct *tsk)
+{
+        write_seqlock(&tsk->vtime_seqlock);
+        __vtime_account_system(tsk);
+        current->flags |= PF_VCPU;
+        write_sequnlock(&tsk->vtime_seqlock);
+}
+
+void vtime_guest_exit(struct task_struct *tsk)
+{
+        write_seqlock(&tsk->vtime_seqlock);
+        __vtime_account_system(tsk);
+        current->flags &= ~PF_VCPU;
+        write_sequnlock(&tsk->vtime_seqlock);
 }
 
 void vtime_account_idle(struct task_struct *tsk)
 {
-        cputime_t delta_cpu = get_vtime_delta();
+        cputime_t delta_cpu = get_vtime_delta(tsk);
 
         account_idle_time(delta_cpu);
 }
@@ -647,4 +704,116 @@ bool vtime_accounting_enabled(void)
 {
         return context_tracking_active();
 }
+
+void arch_vtime_task_switch(struct task_struct *prev)
+{
+        write_seqlock(&prev->vtime_seqlock);
+        prev->vtime_snap_whence = VTIME_SLEEPING;
+        write_sequnlock(&prev->vtime_seqlock);
+
+        write_seqlock(&current->vtime_seqlock);
+        current->vtime_snap_whence = VTIME_SYS;
+        current->vtime_snap = sched_clock();
+        write_sequnlock(&current->vtime_seqlock);
+}
+
+void vtime_init_idle(struct task_struct *t)
+{
+        unsigned long flags;
+
+        write_seqlock_irqsave(&t->vtime_seqlock, flags);
+        t->vtime_snap_whence = VTIME_SYS;
+        t->vtime_snap = sched_clock();
+        write_sequnlock_irqrestore(&t->vtime_seqlock, flags);
+}
+
+cputime_t task_gtime(struct task_struct *t)
+{
+        unsigned long flags;
+        unsigned int seq;
+        cputime_t gtime;
+
+        do {
+                seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags);
+
+                gtime = t->gtime;
+                if (t->flags & PF_VCPU)
+                        gtime += vtime_delta(t);
+
+        } while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags));
+
+        return gtime;
+}
+
+/*
+ * Fetch cputime raw values from fields of task_struct and
+ * add up the pending nohz execution time since the last
+ * cputime snapshot.
+ */
+static void
+fetch_task_cputime(struct task_struct *t,
+                   cputime_t *u_dst, cputime_t *s_dst,
+                   cputime_t *u_src, cputime_t *s_src,
+                   cputime_t *udelta, cputime_t *sdelta)
+{
+        unsigned long flags;
+        unsigned int seq;
+        unsigned long long delta;
+
+        do {
+                *udelta = 0;
+                *sdelta = 0;
+
+                seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags);
+
+                if (u_dst)
+                        *u_dst = *u_src;
+                if (s_dst)
+                        *s_dst = *s_src;
+
+                /* Task is sleeping, nothing to add */
+                if (t->vtime_snap_whence == VTIME_SLEEPING ||
+                    is_idle_task(t))
+                        continue;
+
+                delta = vtime_delta(t);
+
+                /*
+                 * Task runs either in user or kernel space, add pending nohz time to
+                 * the right place.
+                 */
+                if (t->vtime_snap_whence == VTIME_USER || t->flags & PF_VCPU) {
+                        *udelta = delta;
+                } else {
+                        if (t->vtime_snap_whence == VTIME_SYS)
+                                *sdelta = delta;
+                }
+        } while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags));
+}
+
+
+void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime)
+{
+        cputime_t udelta, sdelta;
+
+        fetch_task_cputime(t, utime, stime, &t->utime,
+                           &t->stime, &udelta, &sdelta);
+        if (utime)
+                *utime += udelta;
+        if (stime)
+                *stime += sdelta;
+}
+
+void task_cputime_scaled(struct task_struct *t,
+                         cputime_t *utimescaled, cputime_t *stimescaled)
+{
+        cputime_t udelta, sdelta;
+
+        fetch_task_cputime(t, utimescaled, stimescaled,
+                           &t->utimescaled, &t->stimescaled, &udelta, &sdelta);
+        if (utimescaled)
+                *utimescaled += cputime_to_scaled(udelta);
+        if (stimescaled)
+                *stimescaled += cputime_to_scaled(sdelta);
+}
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
diff --git a/kernel/softirq.c b/kernel/softirq.c
index ed567babe789..f5cc25f147a6 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -221,7 +221,7 @@ asmlinkage void __do_softirq(void)
         current->flags &= ~PF_MEMALLOC;
 
         pending = local_softirq_pending();
-        vtime_account_irq_enter(current);
+        account_irq_enter_time(current);
 
         __local_bh_disable((unsigned long)__builtin_return_address(0),
                                 SOFTIRQ_OFFSET);
@@ -272,7 +272,7 @@ restart:
 
         lockdep_softirq_exit();
 
-        vtime_account_irq_exit(current);
+        account_irq_exit_time(current);
         __local_bh_enable(SOFTIRQ_OFFSET);
         tsk_restore_flags(current, old_flags, PF_MEMALLOC);
 }
@@ -341,7 +341,7 @@ static inline void invoke_softirq(void)
  */
 void irq_exit(void)
 {
-        vtime_account_irq_exit(current);
+        account_irq_exit_time(current);
         trace_hardirq_exit();
         sub_preempt_count(IRQ_EXIT_OFFSET);
         if (!in_interrupt() && local_softirq_pending())