Merge tag 'full-dynticks-cputime-for-mingo' of...

Merge tag 'full-dynticks-cputime-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core

Pull full-dynticks (user-space execution is undisturbed and
receives no timer IRQs) preparation changes that convert the
cputime accounting code to be full-dynticks ready,
from Frederic Weisbecker:

 "This implements the cputime accounting on full dynticks CPUs.

  Typical cputime stats infrastructure relies on the timer tick and
  its periodic polling on the CPU to account the amount of time
  spent by the CPUs and the tasks per high level domains such as
  userspace, kernelspace, guest, ...

  Now we are preparing to implement full dynticks capability on
  Linux for Real Time and HPC users who want full CPU isolation.
  This feature requires a cputime accounting that doesn't depend
  on the timer tick.

  To implement it, this new cputime infrastructure plugs into
  kernel/user/guest boundaries to take snapshots of cputime and
  flush these to the stats when needed. This performs pretty
  much like CONFIG_VIRT_CPU_ACCOUNTING except that context location
  and cputime snaphots are synchronized between write and read
  side such that the latter can safely retrieve the pending tickless
  cputime of a task and add it to its latest cputime snapshot to
  return the correct result to the user."
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

arch/alpha/kernel/osf_sys.c

@@ -1139,6 +1139,7 @@ struct rusage32 {
 SYSCALL_DEFINE2(osf_getrusage, int, who, struct rusage32 __user *, ru)
 {
 	struct rusage32 r;
+	cputime_t utime, stime;
 
 	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
 		return -EINVAL;
@@ -1146,8 +1147,9 @@ SYSCALL_DEFINE2(osf_getrusage, int, who, struct rusage32 __user *, ru)
 	memset(&r, 0, sizeof(r));
 	switch (who) {
 	case RUSAGE_SELF:
-		jiffies_to_timeval32(current->utime, &r.ru_utime);
-		jiffies_to_timeval32(current->stime, &r.ru_stime);
+		task_cputime(current, &utime, &stime);
+		jiffies_to_timeval32(utime, &r.ru_utime);
+		jiffies_to_timeval32(stime, &r.ru_stime);
 		r.ru_minflt = current->min_flt;
 		r.ru_majflt = current->maj_flt;
 		break;

arch/ia64/include/asm/cputime.h

@@ -11,99 +11,19 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  *
- * If we have CONFIG_VIRT_CPU_ACCOUNTING, we measure cpu time in nsec.
+ * If we have CONFIG_VIRT_CPU_ACCOUNTING_NATIVE, we measure cpu time in nsec.
  * Otherwise we measure cpu time in jiffies using the generic definitions.
  */
 
 #ifndef __IA64_CPUTIME_H
 #define __IA64_CPUTIME_H
 
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
-#include <asm-generic/cputime.h>
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+# include <asm-generic/cputime.h>
 #else
-
-#include <linux/time.h>
-#include <linux/jiffies.h>
-#include <asm/processor.h>
-
-typedef u64 __nocast cputime_t;
-typedef u64 __nocast cputime64_t;
-
-#define cputime_one_jiffy		jiffies_to_cputime(1)
-
-/*
- * Convert cputime <-> jiffies (HZ)
- */
-#define cputime_to_jiffies(__ct)	\
-	((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
-#define jiffies_to_cputime(__jif)	\
-	(__force cputime_t)((__jif) * (NSEC_PER_SEC / HZ))
-#define cputime64_to_jiffies64(__ct)	\
-	((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
-#define jiffies64_to_cputime64(__jif)	\
-	(__force cputime64_t)((__jif) * (NSEC_PER_SEC / HZ))
-
-/*
- * Convert cputime <-> microseconds
- */
-#define cputime_to_usecs(__ct)		\
-	((__force u64)(__ct) / NSEC_PER_USEC)
-#define usecs_to_cputime(__usecs)	\
-	(__force cputime_t)((__usecs) * NSEC_PER_USEC)
-#define usecs_to_cputime64(__usecs)	\
-	(__force cputime64_t)((__usecs) * NSEC_PER_USEC)
-
-/*
- * Convert cputime <-> seconds
- */
-#define cputime_to_secs(__ct)		\
-	((__force u64)(__ct) / NSEC_PER_SEC)
-#define secs_to_cputime(__secs)		\
-	(__force cputime_t)((__secs) * NSEC_PER_SEC)
-
-/*
- * Convert cputime <-> timespec (nsec)
- */
-static inline cputime_t timespec_to_cputime(const struct timespec *val)
-{
-	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_nsec;
-	return (__force cputime_t) ret;
-}
-static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
-{
-	val->tv_sec  = (__force u64) ct / NSEC_PER_SEC;
-	val->tv_nsec = (__force u64) ct % NSEC_PER_SEC;
-}
-
-/*
- * Convert cputime <-> timeval (msec)
- */
-static inline cputime_t timeval_to_cputime(struct timeval *val)
-{
-	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_usec * NSEC_PER_USEC;
-	return (__force cputime_t) ret;
-}
-static inline void cputime_to_timeval(const cputime_t ct, struct timeval *val)
-{
-	val->tv_sec = (__force u64) ct / NSEC_PER_SEC;
-	val->tv_usec = ((__force u64) ct % NSEC_PER_SEC) / NSEC_PER_USEC;
-}
-
-/*
- * Convert cputime <-> clock (USER_HZ)
- */
-#define cputime_to_clock_t(__ct)	\
-	((__force u64)(__ct) / (NSEC_PER_SEC / USER_HZ))
-#define clock_t_to_cputime(__x)		\
-	(__force cputime_t)((__x) * (NSEC_PER_SEC / USER_HZ))
-
-/*
- * Convert cputime64 to clock.
- */
-#define cputime64_to_clock_t(__ct)	\
-	cputime_to_clock_t((__force cputime_t)__ct)
-
+# include <asm/processor.h>
+# include <asm-generic/cputime_nsecs.h>
 extern void arch_vtime_task_switch(struct task_struct *tsk);
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
 #endif /* __IA64_CPUTIME_H */

arch/ia64/include/asm/thread_info.h

@@ -31,7 +31,7 @@ struct thread_info {
 	mm_segment_t addr_limit;	/* user-level address space limit */
 	int preempt_count;		/* 0=premptable, <0=BUG; will also serve as bh-counter */
 	struct restart_block restart_block;
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	__u64 ac_stamp;
 	__u64 ac_leave;
 	__u64 ac_stime;
@@ -69,7 +69,7 @@ struct thread_info {
 #define task_stack_page(tsk)	((void *)(tsk))
 
 #define __HAVE_THREAD_FUNCTIONS
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 #define setup_thread_stack(p, org)			\
 	*task_thread_info(p) = *task_thread_info(org);	\
 	task_thread_info(p)->ac_stime = 0;		\

arch/ia64/include/asm/xen/minstate.h

 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 /* read ar.itc in advance, and use it before leaving bank 0 */
 #define XEN_ACCOUNT_GET_STAMP		\
 	MOV_FROM_ITC(pUStk, p6, r20, r2);

arch/ia64/kernel/asm-offsets.c

@@ -41,7 +41,7 @@ void foo(void)
 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
 	DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
 	DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count));
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	DEFINE(TI_AC_STAMP, offsetof(struct thread_info, ac_stamp));
 	DEFINE(TI_AC_LEAVE, offsetof(struct thread_info, ac_leave));
 	DEFINE(TI_AC_STIME, offsetof(struct thread_info, ac_stime));

arch/ia64/kernel/entry.S

@@ -724,7 +724,7 @@ GLOBAL_ENTRY(__paravirt_leave_syscall)
 #endif
 .global __paravirt_work_processed_syscall;
 __paravirt_work_processed_syscall:
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	adds r2=PT(LOADRS)+16,r12
 	MOV_FROM_ITC(pUStk, p9, r22, r19)	// fetch time at leave
 	adds r18=TI_FLAGS+IA64_TASK_SIZE,r13
@@ -762,7 +762,7 @@ __paravirt_work_processed_syscall:
 
 	ld8 r29=[r2],16		// M0|1 load cr.ipsr
 	ld8 r28=[r3],16		// M0|1 load cr.iip
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 (pUStk) add r14=TI_AC_LEAVE+IA64_TASK_SIZE,r13
 	;;
 	ld8 r30=[r2],16		// M0|1 load cr.ifs
@@ -793,7 +793,7 @@ __paravirt_work_processed_syscall:
 	ld8.fill r1=[r3],16			// M0|1 load r1
 (pUStk) mov r17=1				// A
 	;;
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 (pUStk) st1 [r15]=r17				// M2|3
 #else
 (pUStk) st1 [r14]=r17				// M2|3
@@ -813,7 +813,7 @@ __paravirt_work_processed_syscall:
 	shr.u r18=r19,16		// I0|1 get byte size of existing "dirty" partition
 	COVER				// B    add current frame into dirty partition & set cr.ifs
 	;;
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	mov r19=ar.bsp			// M2   get new backing store pointer
 	st8 [r14]=r22			// M	save time at leave
 	mov f10=f0			// F    clear f10
@@ -948,7 +948,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel)
 	adds r16=PT(CR_IPSR)+16,r12
 	adds r17=PT(CR_IIP)+16,r12
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	.pred.rel.mutex pUStk,pKStk
 	MOV_FROM_PSR(pKStk, r22, r29)	// M2 read PSR now that interrupts are disabled
 	MOV_FROM_ITC(pUStk, p9, r22, r29)	// M  fetch time at leave
@@ -981,7 +981,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel)
 	;;
 	ld8.fill r12=[r16],16
 	ld8.fill r13=[r17],16
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 (pUStk)	adds r3=TI_AC_LEAVE+IA64_TASK_SIZE,r18
 #else
 (pUStk)	adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18
@@ -989,7 +989,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel)
 	;;
 	ld8 r20=[r16],16	// ar.fpsr
 	ld8.fill r15=[r17],16
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 (pUStk)	adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18	// deferred
 #endif
 	;;
@@ -997,7 +997,7 @@ GLOBAL_ENTRY(__paravirt_leave_kernel)
 	ld8.fill r2=[r17]
 (pUStk)	mov r17=1
 	;;
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	//  mmi_ :  ld8 st1 shr;;         mmi_ : st8 st1 shr;;
 	//  mib  :  mov add br        ->  mib  : ld8 add br
 	//  bbb_ :  br  nop cover;;       mbb_ : mov br  cover;;

arch/ia64/kernel/fsys.S

@@ -529,7 +529,7 @@ GLOBAL_ENTRY(paravirt_fsys_bubble_down)
 	nop.i 0
 	;;
 	mov ar.rsc=0				// M2   set enforced lazy mode, pl 0, LE, loadrs=0
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	MOV_FROM_ITC(p0, p6, r30, r23)		// M    get cycle for accounting
 #else
 	nop.m 0
@@ -555,7 +555,7 @@ GLOBAL_ENTRY(paravirt_fsys_bubble_down)
 	cmp.ne pKStk,pUStk=r0,r0		// A    set pKStk <- 0, pUStk <- 1
 	br.call.sptk.many b7=ia64_syscall_setup	// B
 	;;
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	// mov.m r30=ar.itc is called in advance
 	add r16=TI_AC_STAMP+IA64_TASK_SIZE,r2
 	add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r2

arch/ia64/kernel/head.S

@@ -1073,7 +1073,7 @@ END(ia64_native_sched_clock)
 sched_clock = ia64_native_sched_clock
 #endif
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 GLOBAL_ENTRY(cycle_to_cputime)
 	alloc r16=ar.pfs,1,0,0,0
 	addl r8=THIS_CPU(ia64_cpu_info) + IA64_CPUINFO_NSEC_PER_CYC_OFFSET,r0
@@ -1091,7 +1091,7 @@ GLOBAL_ENTRY(cycle_to_cputime)
 	shrp r8=r9,r8,IA64_NSEC_PER_CYC_SHIFT
 	br.ret.sptk.many rp
 END(cycle_to_cputime)
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 #ifdef CONFIG_IA64_BRL_EMU
 

arch/ia64/kernel/ivt.S

@@ -784,7 +784,7 @@ ENTRY(break_fault)
 
 (p8)	adds r28=16,r28				// A    switch cr.iip to next bundle
 (p9)	adds r8=1,r8				// A    increment ei to next slot
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	;;
 	mov b6=r30				// I0   setup syscall handler branch reg early
 #else
@@ -801,7 +801,7 @@ ENTRY(break_fault)
 	//
 ///////////////////////////////////////////////////////////////////////
 	st1 [r16]=r0				// M2|3 clear current->thread.on_ustack flag
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	MOV_FROM_ITC(p0, p14, r30, r18)		// M    get cycle for accounting
 #else
 	mov b6=r30				// I0   setup syscall handler branch reg early
@@ -817,7 +817,7 @@ ENTRY(break_fault)
 	cmp.eq p14,p0=r9,r0			// A    are syscalls being traced/audited?
 	br.call.sptk.many b7=ia64_syscall_setup	// B
 1:
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	// mov.m r30=ar.itc is called in advance, and r13 is current
 	add r16=TI_AC_STAMP+IA64_TASK_SIZE,r13	// A
 	add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r13	// A
@@ -1043,7 +1043,7 @@ END(ia64_syscall_setup)
 	DBG_FAULT(16)
 	FAULT(16)
 
-#if defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(__IA64_ASM_PARAVIRTUALIZED_NATIVE)
+#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(__IA64_ASM_PARAVIRTUALIZED_NATIVE)
 	/*
 	 * There is no particular reason for this code to be here, other than
 	 * that there happens to be space here that would go unused otherwise.

arch/ia64/kernel/minstate.h

@@ -4,7 +4,7 @@
 #include "entry.h"
 #include "paravirt_inst.h"
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 /* read ar.itc in advance, and use it before leaving bank 0 */
 #define ACCOUNT_GET_STAMP				\
 (pUStk) mov.m r20=ar.itc;

arch/ia64/kernel/time.c

@@ -77,7 +77,7 @@ static struct clocksource clocksource_itc = {
 };
 static struct clocksource *itc_clocksource;
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 
 #include <linux/kernel_stat.h>
 
@@ -136,13 +136,14 @@ void vtime_account_system(struct task_struct *tsk)
 
 	account_system_time(tsk, 0, delta, delta);
 }
+EXPORT_SYMBOL_GPL(vtime_account_system);
 
 void vtime_account_idle(struct task_struct *tsk)
 {
 	account_idle_time(vtime_delta(tsk));
 }
 
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 static irqreturn_t
 timer_interrupt (int irq, void *dev_id)

arch/powerpc/configs/chroma_defconfig

 CONFIG_PPC64=y
 CONFIG_PPC_BOOK3E_64=y
-# CONFIG_VIRT_CPU_ACCOUNTING is not set
+# CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set
 CONFIG_SMP=y
 CONFIG_NR_CPUS=256
 CONFIG_EXPERIMENTAL=y

arch/powerpc/configs/corenet64_smp_defconfig

 CONFIG_PPC64=y
 CONFIG_PPC_BOOK3E_64=y
-# CONFIG_VIRT_CPU_ACCOUNTING is not set
+# CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set
 CONFIG_SMP=y
 CONFIG_NR_CPUS=2
 CONFIG_EXPERIMENTAL=y

arch/powerpc/configs/pasemi_defconfig

 CONFIG_PPC64=y
 CONFIG_ALTIVEC=y
-# CONFIG_VIRT_CPU_ACCOUNTING is not set
+# CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set
 CONFIG_SMP=y
 CONFIG_NR_CPUS=2
 CONFIG_EXPERIMENTAL=y

arch/powerpc/include/asm/cputime.h

@@ -8,7 +8,7 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  *
- * If we have CONFIG_VIRT_CPU_ACCOUNTING, we measure cpu time in
+ * If we have CONFIG_VIRT_CPU_ACCOUNTING_NATIVE, we measure cpu time in
  * the same units as the timebase.  Otherwise we measure cpu time
  * in jiffies using the generic definitions.
  */
@@ -16,7 +16,7 @@
 #ifndef __POWERPC_CPUTIME_H
 #define __POWERPC_CPUTIME_H
 
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 #include <asm-generic/cputime.h>
 #ifdef __KERNEL__
 static inline void setup_cputime_one_jiffy(void) { }
@@ -231,5 +231,5 @@ static inline cputime_t clock_t_to_cputime(const unsigned long clk)
 static inline void arch_vtime_task_switch(struct task_struct *tsk) { }
 
 #endif /* __KERNEL__ */
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 #endif /* __POWERPC_CPUTIME_H */

arch/powerpc/include/asm/lppaca.h

@@ -145,7 +145,7 @@ struct dtl_entry {
 extern struct kmem_cache *dtl_cache;
 
 /*
- * When CONFIG_VIRT_CPU_ACCOUNTING = y, the cpu accounting code controls
+ * When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE = y, the cpu accounting code controls
  * reading from the dispatch trace log.  If other code wants to consume
  * DTL entries, it can set this pointer to a function that will get
  * called once for each DTL entry that gets processed.

arch/powerpc/include/asm/ppc_asm.h

@@ -24,7 +24,7 @@
  * user_time and system_time fields in the paca.
  */
 
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 #define ACCOUNT_CPU_USER_ENTRY(ra, rb)
 #define ACCOUNT_CPU_USER_EXIT(ra, rb)
 #define ACCOUNT_STOLEN_TIME
@@ -70,7 +70,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
 
 #endif /* CONFIG_PPC_SPLPAR */
 
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 /*
  * Macros for storing registers into and loading registers from

arch/powerpc/kernel/entry_64.S

@@ -94,7 +94,7 @@ system_call_common:
 	addi	r9,r1,STACK_FRAME_OVERHEAD
 	ld	r11,exception_marker@toc(r2)
 	std	r11,-16(r9)		/* "regshere" marker */
-#if defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)
+#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC_SPLPAR)
 BEGIN_FW_FTR_SECTION
 	beq	33f
 	/* if from user, see if there are any DTL entries to process */
@@ -110,7 +110,7 @@ BEGIN_FW_FTR_SECTION
 	addi	r9,r1,STACK_FRAME_OVERHEAD
 33:
 END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING && CONFIG_PPC_SPLPAR */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE && CONFIG_PPC_SPLPAR */
 
 	/*
 	 * A syscall should always be called with interrupts enabled

arch/powerpc/kernel/time.c

@@ -143,7 +143,7 @@ EXPORT_SYMBOL_GPL(ppc_proc_freq);
 unsigned long ppc_tb_freq;
 EXPORT_SYMBOL_GPL(ppc_tb_freq);
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 /*
  * Factors for converting from cputime_t (timebase ticks) to
  * jiffies, microseconds, seconds, and clock_t (1/USER_HZ seconds).
@@ -347,6 +347,7 @@ void vtime_account_system(struct task_struct *tsk)
 	if (stolen)
 		account_steal_time(stolen);
 }
+EXPORT_SYMBOL_GPL(vtime_account_system);
 
 void vtime_account_idle(struct task_struct *tsk)
 {
@@ -377,7 +378,7 @@ void vtime_account_user(struct task_struct *tsk)
 	account_user_time(tsk, utime, utimescaled);
 }
 
-#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
+#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 #define calc_cputime_factors()
 #endif
 

arch/powerpc/platforms/pseries/dtl.c

@@ -57,7 +57,7 @@ static u8 dtl_event_mask = 0x7;
  */
 static int dtl_buf_entries = N_DISPATCH_LOG;
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 struct dtl_ring {
 	u64	write_index;
 	struct dtl_entry *write_ptr;
@@ -142,7 +142,7 @@ static u64 dtl_current_index(struct dtl *dtl)
 	return per_cpu(dtl_rings, dtl->cpu).write_index;
 }
 
-#else /* CONFIG_VIRT_CPU_ACCOUNTING */
+#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 static int dtl_start(struct dtl *dtl)
 {
@@ -188,7 +188,7 @@ static u64 dtl_current_index(struct dtl *dtl)
 {
 	return lppaca_of(dtl->cpu).dtl_idx;
 }
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 static int dtl_enable(struct dtl *dtl)
 {

arch/powerpc/platforms/pseries/setup.c

@@ -281,7 +281,7 @@ static struct notifier_block pci_dn_reconfig_nb = {
 
 struct kmem_cache *dtl_cache;
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 /*
  * Allocate space for the dispatch trace log for all possible cpus
  * and register the buffers with the hypervisor.  This is used for
@@ -332,12 +332,12 @@ static int alloc_dispatch_logs(void)
 
 	return 0;
 }
-#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
+#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 static inline int alloc_dispatch_logs(void)
 {
 	return 0;
 }
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 static int alloc_dispatch_log_kmem_cache(void)
 {

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)

arch/x86/kernel/apm_32.c

@@ -899,6 +899,7 @@ static void apm_cpu_idle(void)
 	static int use_apm_idle; /* = 0 */
 	static unsigned int last_jiffies; /* = 0 */
 	static unsigned int last_stime; /* = 0 */
+	cputime_t stime;
 
 	int apm_idle_done = 0;
 	unsigned int jiffies_since_last_check = jiffies - last_jiffies;
@@ -906,23 +907,23 @@ static void apm_cpu_idle(void)
 
 	WARN_ONCE(1, "deprecated apm_cpu_idle will be deleted in 2012");
 recalc:
+	task_cputime(current, NULL, &stime);
 	if (jiffies_since_last_check > IDLE_CALC_LIMIT) {
 		use_apm_idle = 0;
-		last_jiffies = jiffies;
-		last_stime = current->stime;
 	} else if (jiffies_since_last_check > idle_period) {
 		unsigned int idle_percentage;
 
-		idle_percentage = current->stime - last_stime;
+		idle_percentage = stime - last_stime;
 		idle_percentage *= 100;
 		idle_percentage /= jiffies_since_last_check;
 		use_apm_idle = (idle_percentage > idle_threshold);
 		if (apm_info.forbid_idle)
 			use_apm_idle = 0;
-		last_jiffies = jiffies;
-		last_stime = current->stime;
 	}
 
+	last_jiffies = jiffies;
+	last_stime = stime;
+
 	bucket = IDLE_LEAKY_MAX;
 
 	while (!need_resched()) {

drivers/isdn/mISDN/stack.c

@@ -18,6 +18,7 @@
 #include <linux/slab.h>
 #include <linux/mISDNif.h>
 #include <linux/kthread.h>
+#include <linux/sched.h>
 #include "core.h"
 
 static u_int	*debug;
@@ -202,6 +203,9 @@ static int
 mISDNStackd(void *data)
 {
 	struct mISDNstack *st = data;
+#ifdef MISDN_MSG_STATS
+	cputime_t utime, stime;
+#endif
 	int err = 0;
 
 	sigfillset(&current->blocked);
@@ -303,9 +307,10 @@ mISDNStackd(void *data)
 	       "msg %d sleep %d stopped\n",
 	       dev_name(&st->dev->dev), st->msg_cnt, st->sleep_cnt,
 	       st->stopped_cnt);
+	task_cputime(st->thread, &utime, &stime);
 	printk(KERN_DEBUG
 	       "mISDNStackd daemon for %s utime(%ld) stime(%ld)\n",
-	       dev_name(&st->dev->dev), st->thread->utime, st->thread->stime);
+	       dev_name(&st->dev->dev), utime, stime);
 	printk(KERN_DEBUG
 	       "mISDNStackd daemon for %s nvcsw(%ld) nivcsw(%ld)\n",
 	       dev_name(&st->dev->dev), st->thread->nvcsw, st->thread->nivcsw);

fs/binfmt_elf.c

@@ -33,6 +33,7 @@
 #include <linux/elf.h>
 #include <linux/utsname.h>
 #include <linux/coredump.h>
+#include <linux/sched.h>
 #include <asm/uaccess.h>
 #include <asm/param.h>
 #include <asm/page.h>
@@ -1320,8 +1321,11 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
 		cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
 		cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
 	} else {
-		cputime_to_timeval(p->utime, &prstatus->pr_utime);
-		cputime_to_timeval(p->stime, &prstatus->pr_stime);
+		cputime_t utime, stime;
+
+		task_cputime(p, &utime, &stime);
+		cputime_to_timeval(utime, &prstatus->pr_utime);
+		cputime_to_timeval(stime, &prstatus->pr_stime);
 	}
 	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
 	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);

fs/binfmt_elf_fdpic.c

@@ -1375,8 +1375,11 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
 		cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
 		cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
 	} else {
-		cputime_to_timeval(p->utime, &prstatus->pr_utime);
-		cputime_to_timeval(p->stime, &prstatus->pr_stime);
+		cputime_t utime, stime;
+
+		task_cputime(p, &utime, &stime);
+		cputime_to_timeval(utime, &prstatus->pr_utime);
+		cputime_to_timeval(stime, &prstatus->pr_stime);
 	}
 	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
 	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);

fs/proc/array.c

@@ -449,7 +449,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 			do {
 				min_flt += t->min_flt;
 				maj_flt += t->maj_flt;
-				gtime += t->gtime;
+				gtime += task_gtime(t);
 				t = next_thread(t);
 			} while (t != task);
 
@@ -472,7 +472,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 		min_flt = task->min_flt;
 		maj_flt = task->maj_flt;
 		task_cputime_adjusted(task, &utime, &stime);
-		gtime = task->gtime;
+		gtime = task_gtime(task);
 	}
 
 	/* scale priority and nice values from timeslices to -20..20 */

include/asm-generic/cputime.h

@@ -4,66 +4,12 @@
 #include <linux/time.h>
 #include <linux/jiffies.h>
 
-typedef unsigned long __nocast cputime_t;
-
-#define cputime_one_jiffy		jiffies_to_cputime(1)
-#define cputime_to_jiffies(__ct)	(__force unsigned long)(__ct)
-#define cputime_to_scaled(__ct)		(__ct)
-#define jiffies_to_cputime(__hz)	(__force cputime_t)(__hz)
-
-typedef u64 __nocast cputime64_t;
-
-#define cputime64_to_jiffies64(__ct)	(__force u64)(__ct)
-#define jiffies64_to_cputime64(__jif)	(__force cputime64_t)(__jif)
-
-#define nsecs_to_cputime64(__ct)	\
-	jiffies64_to_cputime64(nsecs_to_jiffies64(__ct))
-
-
-/*
- * Convert cputime to microseconds and back.
- */
-#define cputime_to_usecs(__ct)		\
-	jiffies_to_usecs(cputime_to_jiffies(__ct))
-#define usecs_to_cputime(__usec)	\
-	jiffies_to_cputime(usecs_to_jiffies(__usec))
-#define usecs_to_cputime64(__usec)	\
-	jiffies64_to_cputime64(nsecs_to_jiffies64((__usec) * 1000))
-
-/*
- * Convert cputime to seconds and back.
- */
-#define cputime_to_secs(jif)		(cputime_to_jiffies(jif) / HZ)
-#define secs_to_cputime(sec)		jiffies_to_cputime((sec) * HZ)
-
-/*
- * Convert cputime to timespec and back.
- */
-#define timespec_to_cputime(__val)	\
-	jiffies_to_cputime(timespec_to_jiffies(__val))
-#define cputime_to_timespec(__ct,__val)	\
-	jiffies_to_timespec(cputime_to_jiffies(__ct),__val)
-
-/*
- * Convert cputime to timeval and back.
- */
-#define timeval_to_cputime(__val)	\
-	jiffies_to_cputime(timeval_to_jiffies(__val))
-#define cputime_to_timeval(__ct,__val)	\
-	jiffies_to_timeval(cputime_to_jiffies(__ct),__val)
-
-/*
- * Convert cputime to clock and back.
- */
-#define cputime_to_clock_t(__ct)	\
-	jiffies_to_clock_t(cputime_to_jiffies(__ct))
-#define clock_t_to_cputime(__x)		\
-	jiffies_to_cputime(clock_t_to_jiffies(__x))
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+# include <asm-generic/cputime_jiffies.h>
+#endif
 
-/*
- * Convert cputime64 to clock.
- */
-#define cputime64_to_clock_t(__ct)	\
-	jiffies_64_to_clock_t(cputime64_to_jiffies64(__ct))
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+# include <asm-generic/cputime_nsecs.h>
+#endif
 
 #endif

include/asm-generic/cputime_jiffies.h

+#ifndef _ASM_GENERIC_CPUTIME_JIFFIES_H
+#define _ASM_GENERIC_CPUTIME_JIFFIES_H
+
+typedef unsigned long __nocast cputime_t;
+
+#define cputime_one_jiffy		jiffies_to_cputime(1)
+#define cputime_to_jiffies(__ct)	(__force unsigned long)(__ct)
+#define cputime_to_scaled(__ct)		(__ct)
+#define jiffies_to_cputime(__hz)	(__force cputime_t)(__hz)
+
+typedef u64 __nocast cputime64_t;
+
+#define cputime64_to_jiffies64(__ct)	(__force u64)(__ct)
+#define jiffies64_to_cputime64(__jif)	(__force cputime64_t)(__jif)
+
+
+/*
+ * Convert nanoseconds to cputime
+ */
+#define nsecs_to_cputime64(__nsec)	\
+	jiffies64_to_cputime64(nsecs_to_jiffies64(__nsec))
+#define nsecs_to_cputime(__nsec)	\
+	jiffies_to_cputime(nsecs_to_jiffies(__nsec))
+
+
+/*
+ * Convert cputime to microseconds and back.
+ */
+#define cputime_to_usecs(__ct)		\
+	jiffies_to_usecs(cputime_to_jiffies(__ct))
+#define usecs_to_cputime(__usec)	\
+	jiffies_to_cputime(usecs_to_jiffies(__usec))
+#define usecs_to_cputime64(__usec)	\
+	jiffies64_to_cputime64(nsecs_to_jiffies64((__usec) * 1000))
+
+/*
+ * Convert cputime to seconds and back.
+ */
+#define cputime_to_secs(jif)		(cputime_to_jiffies(jif) / HZ)
+#define secs_to_cputime(sec)		jiffies_to_cputime((sec) * HZ)
+
+/*
+ * Convert cputime to timespec and back.
+ */
+#define timespec_to_cputime(__val)	\
+	jiffies_to_cputime(timespec_to_jiffies(__val))
+#define cputime_to_timespec(__ct,__val)	\
+	jiffies_to_timespec(cputime_to_jiffies(__ct),__val)
+
+/*
+ * Convert cputime to timeval and back.
+ */
+#define timeval_to_cputime(__val)	\
+	jiffies_to_cputime(timeval_to_jiffies(__val))
+#define cputime_to_timeval(__ct,__val)	\
+	jiffies_to_timeval(cputime_to_jiffies(__ct),__val)
+
+/*
+ * Convert cputime to clock and back.
+ */
+#define cputime_to_clock_t(__ct)	\
+	jiffies_to_clock_t(cputime_to_jiffies(__ct))
+#define clock_t_to_cputime(__x)		\
+	jiffies_to_cputime(clock_t_to_jiffies(__x))
+
+/*
+ * Convert cputime64 to clock.
+ */
+#define cputime64_to_clock_t(__ct)	\
+	jiffies_64_to_clock_t(cputime64_to_jiffies64(__ct))
+
+#endif

include/asm-generic/cputime_nsecs.h

+/*
+ * Definitions for measuring cputime in nsecs resolution.
+ *
+ * Based on <arch/ia64/include/asm/cputime.h>
+ *
+ * Copyright (C) 2007 FUJITSU LIMITED
+ * Copyright (C) 2007 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#ifndef _ASM_GENERIC_CPUTIME_NSECS_H
+#define _ASM_GENERIC_CPUTIME_NSECS_H
+
+typedef u64 __nocast cputime_t;
+typedef u64 __nocast cputime64_t;
+
+#define cputime_one_jiffy		jiffies_to_cputime(1)
+
+/*
+ * Convert cputime <-> jiffies (HZ)
+ */
+#define cputime_to_jiffies(__ct)	\
+	((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
+#define cputime_to_scaled(__ct)		(__ct)
+#define jiffies_to_cputime(__jif)	\
+	(__force cputime_t)((__jif) * (NSEC_PER_SEC / HZ))
+#define cputime64_to_jiffies64(__ct)	\
+	((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
+#define jiffies64_to_cputime64(__jif)	\
+	(__force cputime64_t)((__jif) * (NSEC_PER_SEC / HZ))
+
+
+/*
+ * Convert cputime <-> nanoseconds
+ */
+#define nsecs_to_cputime(__nsecs)	((__force u64)(__nsecs))
+
+
+/*
+ * Convert cputime <-> microseconds
+ */
+#define cputime_to_usecs(__ct)		\
+	((__force u64)(__ct) / NSEC_PER_USEC)
+#define usecs_to_cputime(__usecs)	\
+	(__force cputime_t)((__usecs) * NSEC_PER_USEC)
+#define usecs_to_cputime64(__usecs)	\
+	(__force cputime64_t)((__usecs) * NSEC_PER_USEC)
+
+/*
+ * Convert cputime <-> seconds
+ */
+#define cputime_to_secs(__ct)		\
+	((__force u64)(__ct) / NSEC_PER_SEC)
+#define secs_to_cputime(__secs)		\
+	(__force cputime_t)((__secs) * NSEC_PER_SEC)
+
+/*
+ * Convert cputime <-> timespec (nsec)
+ */
+static inline cputime_t timespec_to_cputime(const struct timespec *val)
+{
+	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_nsec;
+	return (__force cputime_t) ret;
+}
+static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
+{
+	val->tv_sec  = (__force u64) ct / NSEC_PER_SEC;
+	val->tv_nsec = (__force u64) ct % NSEC_PER_SEC;
+}
+
+/*
+ * Convert cputime <-> timeval (msec)
+ */
+static inline cputime_t timeval_to_cputime(struct timeval *val)
+{
+	u64 ret = val->tv_sec * NSEC_PER_SEC + val->tv_usec * NSEC_PER_USEC;
+	return (__force cputime_t) ret;
+}
+static inline void cputime_to_timeval(const cputime_t ct, struct timeval *val)
+{
+	val->tv_sec = (__force u64) ct / NSEC_PER_SEC;
+	val->tv_usec = ((__force u64) ct % NSEC_PER_SEC) / NSEC_PER_USEC;
+}
+
+/*
+ * Convert cputime <-> clock (USER_HZ)
+ */
+#define cputime_to_clock_t(__ct)	\
+	((__force u64)(__ct) / (NSEC_PER_SEC / USER_HZ))
+#define clock_t_to_cputime(__x)		\
+	(__force cputime_t)((__x) * (NSEC_PER_SEC / USER_HZ))
+
+/*
+ * Convert cputime64 to clock.
+ */
+#define cputime64_to_clock_t(__ct)	\
+	cputime_to_clock_t((__force cputime_t)__ct)
+
+#endif

include/linux/context_tracking.h

@@ -3,12 +3,40 @@
 
 #ifdef CONFIG_CONTEXT_TRACKING
 #include <linux/sched.h>
+#include <linux/percpu.h>
+
+struct context_tracking {
+	/*
+	 * When active is false, probes are unset in order
+	 * to minimize overhead: TIF flags are cleared
+	 * and calls to user_enter/exit are ignored. This
+	 * may be further optimized using static keys.
+	 */
+	bool active;
+	enum {
+		IN_KERNEL = 0,
+		IN_USER,
+	} state;
+};
+
+DECLARE_PER_CPU(struct context_tracking, context_tracking);
+
+static inline bool context_tracking_in_user(void)
+{
+	return __this_cpu_read(context_tracking.state) == IN_USER;
+}
+
+static inline bool context_tracking_active(void)
+{
+	return __this_cpu_read(context_tracking.active);
+}
 
 extern void user_enter(void);
 extern void user_exit(void);
 extern void context_tracking_task_switch(struct task_struct *prev,
 					 struct task_struct *next);
 #else
+static inline bool context_tracking_in_user(void) { return false; }
 static inline void user_enter(void) { }
 static inline void user_exit(void) { }
 static inline void context_tracking_task_switch(struct task_struct *prev,

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)
 

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)							\
 }
 
 

include/linux/kernel_stat.h

@@ -127,7 +127,7 @@ extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t)
 extern void account_steal_time(cputime_t);
 extern void account_idle_time(cputime_t);
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 static inline void account_process_tick(struct task_struct *tsk, int user)
 {
 	vtime_account_user(tsk);

include/linux/kvm_host.h

@@ -22,6 +22,7 @@
 #include <linux/rcupdate.h>
 #include <linux/ratelimit.h>
 #include <linux/err.h>
+#include <linux/irqflags.h>
 #include <asm/signal.h>
 
 #include <linux/kvm.h>
@@ -740,15 +741,52 @@ static inline int kvm_deassign_device(struct kvm *kvm,
 }
 #endif /* CONFIG_IOMMU_API */
 
-static inline void kvm_guest_enter(void)
+static inline void __guest_enter(void)
 {
-	BUG_ON(preemptible());
 	/*
 	 * This is running in ioctl context so we can avoid
 	 * the call to vtime_account() with its unnecessary idle check.
 	 */
-	vtime_account_system_irqsafe(current);
+	vtime_account_system(current);
 	current->flags |= PF_VCPU;
+}
+
+static inline void __guest_exit(void)
+{
+	/*
+	 * This is running in ioctl context so we can avoid
+	 * the call to vtime_account() with its unnecessary idle check.
+	 */
+	vtime_account_system(current);
+	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;
+
+	BUG_ON(preemptible());
+
+	local_irq_save(flags);
+	guest_enter();
+	local_irq_restore(flags);
+
 	/* KVM does not hold any references to rcu protected data when it
 	 * switches CPU into a guest mode. In fact switching to a guest mode
 	 * is very similar to exiting to userspase from rcu point of view. In
@@ -761,12 +799,11 @@ static inline void kvm_guest_enter(void)
 
 static inline void kvm_guest_exit(void)
 {
-	/*
-	 * This is running in ioctl context so we can avoid
-	 * the call to vtime_account() with its unnecessary idle check.
-	 */
-	vtime_account_system_irqsafe(current);
-	current->flags &= ~PF_VCPU;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	guest_exit();
+	local_irq_restore(flags);
 }
 
 /*

include/linux/sched.h

@@ -1368,6 +1368,15 @@ struct task_struct {
 	cputime_t gtime;
 #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 */
@@ -1793,6 +1802,37 @@ static inline void put_task_struct(struct task_struct *t)
 		__put_task_struct(t);
 }
 
+#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)
+{
+	if (utime)
+		*utime = t->utime;
+	if (stime)
+		*stime = t->stime;
+}
+
+static inline void task_cputime_scaled(struct task_struct *t,
+				       cputime_t *utimescaled,
+				       cputime_t *stimescaled)
+{
+	if (utimescaled)
+		*utimescaled = t->utimescaled;
+	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);
 

include/linux/tsacct_kern.h

@@ -23,12 +23,15 @@ static inline void bacct_add_tsk(struct user_namespace *user_ns,
 #ifdef CONFIG_TASK_XACCT
 extern void xacct_add_tsk(struct taskstats *stats, struct task_struct *p);
 extern void acct_update_integrals(struct task_struct *tsk);
+extern void acct_account_cputime(struct task_struct *tsk);
 extern void acct_clear_integrals(struct task_struct *tsk);
 #else
 static inline void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
 {}
 static inline void acct_update_integrals(struct task_struct *tsk)
 {}
+static inline void acct_account_cputime(struct task_struct *tsk)
+{}
 static inline void acct_clear_integrals(struct task_struct *tsk)
 {}
 #endif /* CONFIG_TASK_XACCT */

include/linux/vtime.h

@@ -6,15 +6,46 @@ struct task_struct;
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 extern void vtime_task_switch(struct task_struct *prev);
 extern void vtime_account_system(struct task_struct *tsk);
-extern void vtime_account_system_irqsafe(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);
-#else
+extern void vtime_account_irq_enter(struct task_struct *tsk);
+
+#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_system_irqsafe(struct task_struct *tsk) { }
-static inline void vtime_account(struct task_struct *tsk) { }
+static inline void vtime_account_user(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
+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
@@ -23,25 +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);
 }
 

init/Kconfig

@@ -326,6 +326,9 @@ source "kernel/time/Kconfig"
 
 menu "CPU/Task time and stats accounting"
 
+config VIRT_CPU_ACCOUNTING
+	bool
+
 choice
 	prompt "Cputime accounting"
 	default TICK_CPU_ACCOUNTING if !PPC64
@@ -342,9 +345,10 @@ config TICK_CPU_ACCOUNTING
 
 	  If unsure, say Y.
 
-config VIRT_CPU_ACCOUNTING
+config VIRT_CPU_ACCOUNTING_NATIVE
 	bool "Deterministic task and CPU time accounting"
 	depends on HAVE_VIRT_CPU_ACCOUNTING
+	select VIRT_CPU_ACCOUNTING
 	help
 	  Select this option to enable more accurate task and CPU time
 	  accounting.  This is done by reading a CPU counter on each
@@ -354,6 +358,23 @@ config VIRT_CPU_ACCOUNTING
 	  this also enables accounting of stolen time on logically-partitioned
 	  systems.
 
+config VIRT_CPU_ACCOUNTING_GEN
+	bool "Full dynticks CPU time accounting"
+	depends on HAVE_CONTEXT_TRACKING && 64BIT
+	select VIRT_CPU_ACCOUNTING
+	select CONTEXT_TRACKING
+	help
+	  Select this option to enable task and CPU time accounting on full
+	  dynticks systems. This accounting is implemented by watching every
+	  kernel-user boundaries using the context tracking subsystem.
+	  The accounting is thus performed at the expense of some significant
+	  overhead.
+
+	  For now this is only useful if you are working on the full
+	  dynticks subsystem development.
+
+	  If unsure, say N.
+
 config IRQ_TIME_ACCOUNTING
 	bool "Fine granularity task level IRQ time accounting"
 	depends on HAVE_IRQ_TIME_ACCOUNTING

kernel/acct.c

@@ -566,6 +566,7 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 void acct_collect(long exitcode, int group_dead)
 {
 	struct pacct_struct *pacct = &current->signal->pacct;
+	cputime_t utime, stime;
 	unsigned long vsize = 0;
 
 	if (group_dead && current->mm) {
@@ -593,8 +594,9 @@ void acct_collect(long exitcode, int group_dead)
 		pacct->ac_flag |= ACORE;
 	if (current->flags & PF_SIGNALED)
 		pacct->ac_flag |= AXSIG;
-	pacct->ac_utime += current->utime;
-	pacct->ac_stime += current->stime;
+	task_cputime(current, &utime, &stime);
+	pacct->ac_utime += utime;
+	pacct->ac_stime += stime;
 	pacct->ac_minflt += current->min_flt;
 	pacct->ac_majflt += current->maj_flt;
 	spin_unlock_irq(&current->sighand->siglock);

kernel/context_tracking.c

 #include <linux/context_tracking.h>
+#include <linux/kvm_host.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
-#include <linux/percpu.h>
 #include <linux/hardirq.h>
+#include <linux/export.h>
 
-struct context_tracking {
-	/*
-	 * When active is false, hooks are not set to
-	 * minimize overhead: TIF flags are cleared
-	 * and calls to user_enter/exit are ignored. This
-	 * may be further optimized using static keys.
-	 */
-	bool active;
-	enum {
-		IN_KERNEL = 0,
-		IN_USER,
-	} state;
-};
-
-static DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
+DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
 #ifdef CONFIG_CONTEXT_TRACKING_FORCE
 	.active = true,
 #endif
@@ -44,8 +31,9 @@ void user_enter(void)
 	local_irq_save(flags);
 	if (__this_cpu_read(context_tracking.active) &&
 	    __this_cpu_read(context_tracking.state) != IN_USER) {
-		__this_cpu_write(context_tracking.state, IN_USER);
+		vtime_user_enter(current);
 		rcu_user_enter();
+		__this_cpu_write(context_tracking.state, IN_USER);
 	}
 	local_irq_restore(flags);
 }
@@ -67,12 +55,31 @@ void user_exit(void)
 
 	local_irq_save(flags);
 	if (__this_cpu_read(context_tracking.state) == IN_USER) {
-		__this_cpu_write(context_tracking.state, IN_KERNEL);
 		rcu_user_exit();
+		vtime_user_exit(current);
+		__this_cpu_write(context_tracking.state, IN_KERNEL);
 	}
 	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)
 {

kernel/cpu.c

@@ -224,11 +224,13 @@ void clear_tasks_mm_cpumask(int cpu)
 static inline void check_for_tasks(int cpu)
 {
 	struct task_struct *p;
+	cputime_t utime, stime;
 
 	write_lock_irq(&tasklist_lock);
 	for_each_process(p) {
+		task_cputime(p, &utime, &stime);
 		if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
-		    (p->utime || p->stime))
+		    (utime || stime))
 			printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d "
 				"(state = %ld, flags = %x)\n",
 				p->comm, task_pid_nr(p), cpu,

kernel/delayacct.c

@@ -106,6 +106,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 	unsigned long long t2, t3;
 	unsigned long flags;
 	struct timespec ts;
+	cputime_t utime, stime, stimescaled, utimescaled;
 
 	/* Though tsk->delays accessed later, early exit avoids
 	 * unnecessary returning of other data
@@ -114,12 +115,14 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 		goto done;
 
 	tmp = (s64)d->cpu_run_real_total;
-	cputime_to_timespec(tsk->utime + tsk->stime, &ts);
+	task_cputime(tsk, &utime, &stime);
+	cputime_to_timespec(utime + stime, &ts);
 	tmp += timespec_to_ns(&ts);
 	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
 
 	tmp = (s64)d->cpu_scaled_run_real_total;
-	cputime_to_timespec(tsk->utimescaled + tsk->stimescaled, &ts);
+	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
+	cputime_to_timespec(utimescaled + stimescaled, &ts);
 	tmp += timespec_to_ns(&ts);
 	d->cpu_scaled_run_real_total =
 		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;

kernel/exit.c

@@ -85,6 +85,7 @@ static void __exit_signal(struct task_struct *tsk)
 	bool group_dead = thread_group_leader(tsk);
 	struct sighand_struct *sighand;
 	struct tty_struct *uninitialized_var(tty);
+	cputime_t utime, stime;
 
 	sighand = rcu_dereference_check(tsk->sighand,
 					lockdep_tasklist_lock_is_held());
@@ -123,9 +124,10 @@ static void __exit_signal(struct task_struct *tsk)
 		 * We won't ever get here for the group leader, since it
 		 * will have been the last reference on the signal_struct.
 		 */
-		sig->utime += tsk->utime;
-		sig->stime += tsk->stime;
-		sig->gtime += tsk->gtime;
+		task_cputime(tsk, &utime, &stime);
+		sig->utime += utime;
+		sig->stime += stime;
+		sig->gtime += task_gtime(tsk);
 		sig->min_flt += tsk->min_flt;
 		sig->maj_flt += tsk->maj_flt;
 		sig->nvcsw += tsk->nvcsw;
@@ -1092,7 +1094,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 		sig = p->signal;
 		psig->cutime += tgutime + sig->cutime;
 		psig->cstime += tgstime + sig->cstime;
-		psig->cgtime += p->gtime + sig->gtime + sig->cgtime;
+		psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
 		psig->cmin_flt +=
 			p->min_flt + sig->min_flt + sig->cmin_flt;
 		psig->cmaj_flt +=

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

kernel/posix-cpu-timers.c

@@ -155,11 +155,19 @@ static void bump_cpu_timer(struct k_itimer *timer,
 
 static inline cputime_t prof_ticks(struct task_struct *p)
 {
-	return p->utime + p->stime;
+	cputime_t utime, stime;
+
+	task_cputime(p, &utime, &stime);
+
+	return utime + stime;
 }
 static inline cputime_t virt_ticks(struct task_struct *p)
 {
-	return p->utime;
+	cputime_t utime;
+
+	task_cputime(p, &utime, NULL);
+
+	return utime;
 }
 
 static int
@@ -471,18 +479,23 @@ static void cleanup_timers(struct list_head *head,
  */
 void posix_cpu_timers_exit(struct task_struct *tsk)
 {
+	cputime_t utime, stime;
+
 	add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
 						sizeof(unsigned long long));
+	task_cputime(tsk, &utime, &stime);
 	cleanup_timers(tsk->cpu_timers,
-		       tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
+		       utime, stime, tsk->se.sum_exec_runtime);
 
 }
 void posix_cpu_timers_exit_group(struct task_struct *tsk)
 {
 	struct signal_struct *const sig = tsk->signal;
+	cputime_t utime, stime;
 
+	task_cputime(tsk, &utime, &stime);
 	cleanup_timers(tsk->signal->cpu_timers,
-		       tsk->utime + sig->utime, tsk->stime + sig->stime,
+		       utime + sig->utime, stime + sig->stime,
 		       tsk->se.sum_exec_runtime + sig->sum_sched_runtime);
 }
 
@@ -1226,11 +1239,14 @@ static inline int task_cputime_expired(const struct task_cputime *sample,
 static inline int fastpath_timer_check(struct task_struct *tsk)
 {
 	struct signal_struct *sig;
+	cputime_t utime, stime;
+
+	task_cputime(tsk, &utime, &stime);
 
 	if (!task_cputime_zero(&tsk->cputime_expires)) {
 		struct task_cputime task_sample = {
-			.utime = tsk->utime,
-			.stime = tsk->stime,
+			.utime = utime,
+			.stime = stime,
 			.sum_exec_runtime = tsk->se.sum_exec_runtime
 		};
 

kernel/sched/core.c

@@ -4667,6 +4667,7 @@ 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

kernel/sched/cputime.c

@@ -3,6 +3,7 @@
 #include <linux/tsacct_kern.h>
 #include <linux/kernel_stat.h>
 #include <linux/static_key.h>
+#include <linux/context_tracking.h>
 #include "sched.h"
 
 
@@ -163,7 +164,7 @@ void account_user_time(struct task_struct *p, cputime_t cputime,
 	task_group_account_field(p, index, (__force u64) cputime);
 
 	/* Account for user time used */
-	acct_update_integrals(p);
+	acct_account_cputime(p);
 }
 
 /*
@@ -213,7 +214,7 @@ void __account_system_time(struct task_struct *p, cputime_t cputime,
 	task_group_account_field(p, index, (__force u64) cputime);
 
 	/* Account for system time used */
-	acct_update_integrals(p);
+	acct_account_cputime(p);
 }
 
 /*
@@ -295,6 +296,7 @@ static __always_inline bool steal_account_process_tick(void)
 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
 {
 	struct signal_struct *sig = tsk->signal;
+	cputime_t utime, stime;
 	struct task_struct *t;
 
 	times->utime = sig->utime;
@@ -308,16 +310,15 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
 
 	t = tsk;
 	do {
-		times->utime += t->utime;
-		times->stime += t->stime;
+		task_cputime(tsk, &utime, &stime);
+		times->utime += utime;
+		times->stime += stime;
 		times->sum_exec_runtime += task_sched_runtime(t);
 	} while_each_thread(tsk, t);
 out:
 	rcu_read_unlock();
 }
 
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
-
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 /*
  * Account a tick to a process and cpustat
@@ -382,11 +383,12 @@ static void irqtime_account_idle_ticks(int ticks)
 		irqtime_account_process_tick(current, 0, rq);
 }
 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
-static void irqtime_account_idle_ticks(int ticks) {}
-static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+static inline void irqtime_account_idle_ticks(int ticks) {}
+static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
 						struct rq *rq) {}
 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
 
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 /*
  * Account a single tick of cpu time.
  * @p: the process that the cpu time gets accounted to
@@ -397,6 +399,9 @@ void account_process_tick(struct task_struct *p, int user_tick)
 	cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
 	struct rq *rq = this_rq();
 
+	if (vtime_accounting_enabled())
+		return;
+
 	if (sched_clock_irqtime) {
 		irqtime_account_process_tick(p, user_tick, rq);
 		return;
@@ -438,8 +443,7 @@ void account_idle_ticks(unsigned long ticks)
 
 	account_idle_time(jiffies_to_cputime(ticks));
 }
-
-#endif
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
 
 /*
  * Use precise platform statistics if available:
@@ -461,25 +465,20 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime
 	*st = cputime.stime;
 }
 
-void vtime_account_system_irqsafe(struct task_struct *tsk)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	vtime_account_system(tsk);
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(vtime_account_system_irqsafe);
-
 #ifndef __ARCH_HAS_VTIME_TASK_SWITCH
 void vtime_task_switch(struct task_struct *prev)
 {
+	if (!vtime_accounting_enabled())
+		return;
+
 	if (is_idle_task(prev))
 		vtime_account_idle(prev);
 	else
 		vtime_account_system(prev);
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	vtime_account_user(prev);
+#endif
 	arch_vtime_task_switch(prev);
 }
 #endif
@@ -493,21 +492,34 @@ 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 (in_interrupt() || !is_idle_task(tsk))
-		vtime_account_system(tsk);
-	else
-		vtime_account_idle(tsk);
+	if (!vtime_accounting_enabled())
+		return;
+
+	if (!in_interrupt()) {
+		/*
+		 * If we interrupted user, context_tracking_in_user()
+		 * is 1 because the context tracking don't hook
+		 * on irq entry/exit. This way we know if
+		 * we need to flush user time on kernel entry.
+		 */
+		if (context_tracking_in_user()) {
+			vtime_account_user(tsk);
+			return;
+		}
+
+		if (is_idle_task(tsk)) {
+			vtime_account_idle(tsk);
+			return;
+		}
+	}
+	vtime_account_system(tsk);
 }
-EXPORT_SYMBOL_GPL(vtime_account);
+EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
 #endif /* __ARCH_HAS_VTIME_ACCOUNT */
 
-#else
-
-#ifndef nsecs_to_cputime
-# define nsecs_to_cputime(__nsecs)	nsecs_to_jiffies(__nsecs)
-#endif
+#else /* !CONFIG_VIRT_CPU_ACCOUNTING */
 
 static cputime_t scale_stime(cputime_t stime, cputime_t rtime, cputime_t total)
 {
@@ -568,11 +580,10 @@ static void cputime_adjust(struct task_cputime *curr,
 void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
 {
 	struct task_cputime cputime = {
-		.utime = p->utime,
-		.stime = p->stime,
 		.sum_exec_runtime = p->se.sum_exec_runtime,
 	};
 
+	task_cputime(p, &cputime.utime, &cputime.stime);
 	cputime_adjust(&cputime, &p->prev_cputime, ut, st);
 }
 
@@ -586,4 +597,223 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime
 	thread_group_cputime(p, &cputime);
 	cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
 }
-#endif
+#endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
+static unsigned long long vtime_delta(struct task_struct *tsk)
+{
+	unsigned long long clock;
+
+	clock = sched_clock();
+	if (clock < tsk->vtime_snap)
+		return 0;
+
+	return clock - tsk->vtime_snap;
+}
+
+static cputime_t get_vtime_delta(struct task_struct *tsk)
+{
+	unsigned long long delta = vtime_delta(tsk);
+
+	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)
+{
+	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;
+
+	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)
+{
+	cputime_t delta_cpu;
+
+	if (!vtime_accounting_enabled())
+		return;
+
+	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(tsk);
+
+	account_idle_time(delta_cpu);
+}
+
+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 */

kernel/signal.c

@@ -1632,6 +1632,7 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
 	unsigned long flags;
 	struct sighand_struct *psig;
 	bool autoreap = false;
+	cputime_t utime, stime;
 
 	BUG_ON(sig == -1);
 
@@ -1669,8 +1670,9 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
 				       task_uid(tsk));
 	rcu_read_unlock();
 
-	info.si_utime = cputime_to_clock_t(tsk->utime + tsk->signal->utime);
-	info.si_stime = cputime_to_clock_t(tsk->stime + tsk->signal->stime);
+	task_cputime(tsk, &utime, &stime);
+	info.si_utime = cputime_to_clock_t(utime + tsk->signal->utime);
+	info.si_stime = cputime_to_clock_t(stime + tsk->signal->stime);
 
 	info.si_status = tsk->exit_code & 0x7f;
 	if (tsk->exit_code & 0x80)
@@ -1734,6 +1736,7 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
 	unsigned long flags;
 	struct task_struct *parent;
 	struct sighand_struct *sighand;
+	cputime_t utime, stime;
 
 	if (for_ptracer) {
 		parent = tsk->parent;
@@ -1752,8 +1755,9 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
 	info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
 	rcu_read_unlock();
 
-	info.si_utime = cputime_to_clock_t(tsk->utime);
-	info.si_stime = cputime_to_clock_t(tsk->stime);
+	task_cputime(tsk, &utime, &stime);
+	info.si_utime = cputime_to_clock_t(utime);
+	info.si_stime = cputime_to_clock_t(stime);
 
  	info.si_code = why;
  	switch (why) {

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 @@ asmlinkage void __do_softirq(void)
 
 	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())

kernel/time/tick-sched.c

@@ -631,8 +631,11 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
 
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
-#ifndef CONFIG_VIRT_CPU_ACCOUNTING
+#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	unsigned long ticks;
+
+	if (vtime_accounting_enabled())
+		return;
 	/*
 	 * We stopped the tick in idle. Update process times would miss the
 	 * time we slept as update_process_times does only a 1 tick

kernel/tsacct.c

@@ -32,6 +32,7 @@ void bacct_add_tsk(struct user_namespace *user_ns,
 {
 	const struct cred *tcred;
 	struct timespec uptime, ts;
+	cputime_t utime, stime, utimescaled, stimescaled;
 	u64 ac_etime;
 
 	BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
@@ -65,10 +66,15 @@ void bacct_add_tsk(struct user_namespace *user_ns,
 	stats->ac_ppid	 = pid_alive(tsk) ?
 		task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;
 	rcu_read_unlock();
-	stats->ac_utime = cputime_to_usecs(tsk->utime);
-	stats->ac_stime = cputime_to_usecs(tsk->stime);
-	stats->ac_utimescaled = cputime_to_usecs(tsk->utimescaled);
-	stats->ac_stimescaled = cputime_to_usecs(tsk->stimescaled);
+
+	task_cputime(tsk, &utime, &stime);
+	stats->ac_utime = cputime_to_usecs(utime);
+	stats->ac_stime = cputime_to_usecs(stime);
+
+	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
+	stats->ac_utimescaled = cputime_to_usecs(utimescaled);
+	stats->ac_stimescaled = cputime_to_usecs(stimescaled);
+
 	stats->ac_minflt = tsk->min_flt;
 	stats->ac_majflt = tsk->maj_flt;
 
@@ -115,11 +121,8 @@ void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
 #undef KB
 #undef MB
 
-/**
- * acct_update_integrals - update mm integral fields in task_struct
- * @tsk: task_struct for accounting
- */
-void acct_update_integrals(struct task_struct *tsk)
+static void __acct_update_integrals(struct task_struct *tsk,
+				    cputime_t utime, cputime_t stime)
 {
 	if (likely(tsk->mm)) {
 		cputime_t time, dtime;
@@ -128,7 +131,7 @@ void acct_update_integrals(struct task_struct *tsk)
 		u64 delta;
 
 		local_irq_save(flags);
-		time = tsk->stime + tsk->utime;
+		time = stime + utime;
 		dtime = time - tsk->acct_timexpd;
 		jiffies_to_timeval(cputime_to_jiffies(dtime), &value);
 		delta = value.tv_sec;
@@ -144,6 +147,27 @@ void acct_update_integrals(struct task_struct *tsk)
 	}
 }
 
+/**
+ * acct_update_integrals - update mm integral fields in task_struct
+ * @tsk: task_struct for accounting
+ */
+void acct_update_integrals(struct task_struct *tsk)
+{
+	cputime_t utime, stime;
+
+	task_cputime(tsk, &utime, &stime);
+	__acct_update_integrals(tsk, utime, stime);
+}
+
+/**
+ * acct_account_cputime - update mm integral after cputime update
+ * @tsk: task_struct for accounting
+ */
+void acct_account_cputime(struct task_struct *tsk)
+{
+	__acct_update_integrals(tsk, tsk->utime, tsk->stime);
+}
+
 /**
  * acct_clear_integrals - clear the mm integral fields in task_struct
  * @tsk: task_struct whose accounting fields are cleared