9 files changed, 302 insertions, 1 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index dff9edfc7465..c3567727c13c 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -280,6 +280,17 @@ config FORCE_MAX_ZONEORDER
         default "17" if HUGETLB_PAGE
         default "11"
 
+config VIRT_CPU_ACCOUNTING
+        bool "Deterministic task and CPU time accounting"
+        default n
+        help
+          Select this option to enable more accurate task and CPU time
+          accounting.  This is done by reading a CPU counter on each
+          kernel entry and exit and on transitions within the kernel
+          between system, softirq and hardirq state, so there is a
+          small performance impact.
+          If in doubt, say N here.
+
 config SMP
         bool "Symmetric multi-processing support"
         help
diff --git a/arch/ia64/ia32/elfcore32.h b/arch/ia64/ia32/elfcore32.h
index 446c9aac924d..9a3abf58cea3 100644
--- a/arch/ia64/ia32/elfcore32.h
+++ b/arch/ia64/ia32/elfcore32.h
@@ -30,7 +30,19 @@ struct elf_siginfo
         int     si_errno;                       /* errno */
 };
 
-#define jiffies_to_timeval(a,b) do { (b)->tv_usec = 0; (b)->tv_sec = (a)/HZ; }while(0)
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+/*
+ * Hacks are here since types between compat_timeval (= pair of s32) and
+ * ia64-native timeval (= pair of s64) are not compatible, at least a file
+ * arch/ia64/ia32/../../../fs/binfmt_elf.c will get warnings from compiler on
+ * use of cputime_to_timeval(), which usually an alias of jiffies_to_timeval().
+ */
+#define cputime_to_timeval(a,b) \
+        do { (b)->tv_usec = 0; (b)->tv_sec = (a)/NSEC_PER_SEC; } while(0)
+#else
+#define jiffies_to_timeval(a,b) \
+        do { (b)->tv_usec = 0; (b)->tv_sec = (a)/HZ; } while(0)
+#endif
 
 struct elf_prstatus
 {
diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c
index 0aebc6f79e95..5865130b0a92 100644
--- a/arch/ia64/kernel/asm-offsets.c
+++ b/arch/ia64/kernel/asm-offsets.c
@@ -39,6 +39,12 @@ 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
+        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));
+        DEFINE(TI_AC_UTIME, offsetof(struct thread_info, ac_utime));
+#endif
 
         BLANK();
 
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 3c331c464b40..b0be4a280174 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -710,6 +710,16 @@ ENTRY(ia64_leave_syscall)
 (pUStk) cmp.eq.unc p6,p0=r0,r0          // p6 <- pUStk
 #endif
 .work_processed_syscall:
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+        adds r2=PT(LOADRS)+16,r12
+(pUStk) mov.m r22=ar.itc                        // fetch time at leave
+        adds r18=TI_FLAGS+IA64_TASK_SIZE,r13
+        ;;
+(p6)    ld4 r31=[r18]                           // load current_thread_info()->flags
+        ld8 r19=[r2],PT(B6)-PT(LOADRS)          // load ar.rsc value for "loadrs"
+        adds r3=PT(AR_BSPSTORE)+16,r12          // deferred
+        ;;
+#else
         adds r2=PT(LOADRS)+16,r12
         adds r3=PT(AR_BSPSTORE)+16,r12
         adds r18=TI_FLAGS+IA64_TASK_SIZE,r13
@@ -718,6 +728,7 @@ ENTRY(ia64_leave_syscall)
         ld8 r19=[r2],PT(B6)-PT(LOADRS)          // load ar.rsc value for "loadrs"
         nop.i 0
         ;;
+#endif
         mov r16=ar.bsp                          // M2  get existing backing store pointer
         ld8 r18=[r2],PT(R9)-PT(B6)              // load b6
 (p6)    and r15=TIF_WORK_MASK,r31               // any work other than TIF_SYSCALL_TRACE?
@@ -737,12 +748,21 @@ ENTRY(ia64_leave_syscall)
 
         ld8 r29=[r2],16         // M0|1 load cr.ipsr
         ld8 r28=[r3],16         // M0|1 load cr.iip
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+(pUStk) add r14=TI_AC_LEAVE+IA64_TASK_SIZE,r13
+        ;;
+        ld8 r30=[r2],16         // M0|1 load cr.ifs
+        ld8 r25=[r3],16         // M0|1 load ar.unat
+(pUStk) add r15=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13
+        ;;
+#else
         mov r22=r0              // A    clear r22
         ;;
         ld8 r30=[r2],16         // M0|1 load cr.ifs
         ld8 r25=[r3],16         // M0|1 load ar.unat
 (pUStk) add r14=IA64_TASK_THREAD_ON_USTACK_OFFSET,r13
         ;;
+#endif
         ld8 r26=[r2],PT(B0)-PT(AR_PFS)  // M0|1 load ar.pfs
 (pKStk) mov r22=psr                     // M2   read PSR now that interrupts are disabled
         nop 0
@@ -759,7 +779,11 @@ ENTRY(ia64_leave_syscall)
         ld8.fill r1=[r3],16                     // M0|1 load r1
 (pUStk) mov r17=1                               // A
         ;;
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+(pUStk) st1 [r15]=r17                           // M2|3
+#else
 (pUStk) st1 [r14]=r17                           // M2|3
+#endif
         ld8.fill r13=[r3],16                    // M0|1
         mov f8=f0                               // F    clear f8
         ;;
@@ -775,12 +799,22 @@ ENTRY(ia64_leave_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
+        mov r19=ar.bsp                  // M2   get new backing store pointer
+        st8 [r14]=r22                   // M    save time at leave
+        mov f10=f0                      // F    clear f10
+
+        mov r22=r0                      // A    clear r22
+        movl r14=__kernel_syscall_via_epc // X
+        ;;
+#else
         mov r19=ar.bsp                  // M2   get new backing store pointer
         mov f10=f0                      // F    clear f10
 
         nop.m 0
         movl r14=__kernel_syscall_via_epc // X
         ;;
+#endif
         mov.m ar.csd=r0                 // M2   clear ar.csd
         mov.m ar.ccv=r0                 // M2   clear ar.ccv
         mov b7=r14                      // I0   clear b7 (hint with __kernel_syscall_via_epc)
@@ -913,10 +947,18 @@ GLOBAL_ENTRY(ia64_leave_kernel)
         adds r16=PT(CR_IPSR)+16,r12
         adds r17=PT(CR_IIP)+16,r12
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+        .pred.rel.mutex pUStk,pKStk
+(pKStk) mov r22=psr             // M2 read PSR now that interrupts are disabled
+(pUStk) mov.m r22=ar.itc        // M  fetch time at leave
+        nop.i 0
+        ;;
+#else
 (pKStk) mov r22=psr             // M2 read PSR now that interrupts are disabled
         nop.i 0
         nop.i 0
         ;;
+#endif
         ld8 r29=[r16],16        // load cr.ipsr
         ld8 r28=[r17],16        // load cr.iip
         ;;
@@ -938,15 +980,37 @@ GLOBAL_ENTRY(ia64_leave_kernel)
         ;;
         ld8.fill r12=[r16],16
         ld8.fill r13=[r17],16
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+(pUStk) adds r3=TI_AC_LEAVE+IA64_TASK_SIZE,r18
+#else
 (pUStk) adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18
+#endif
         ;;
         ld8 r20=[r16],16        // ar.fpsr
         ld8.fill r15=[r17],16
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+(pUStk) adds r18=IA64_TASK_THREAD_ON_USTACK_OFFSET,r18  // deferred
+#endif
         ;;
         ld8.fill r14=[r16],16
         ld8.fill r2=[r17]
 (pUStk) mov r17=1
         ;;
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+        //  mmi_ :  ld8 st1 shr;;         mmi_ : st8 st1 shr;;
+        //  mib  :  mov add br        ->  mib  : ld8 add br
+        //  bbb_ :  br  nop cover;;       mbb_ : mov br  cover;;
+        //
+        //  no one require bsp in r16 if (pKStk) branch is selected.
+(pUStk) st8 [r3]=r22            // save time at leave
+(pUStk) st1 [r18]=r17           // restore current->thread.on_ustack
+        shr.u r18=r19,16        // get byte size of existing "dirty" partition
+        ;;
+        ld8.fill r3=[r16]       // deferred
+        LOAD_PHYS_STACK_REG_SIZE(r17)
+(pKStk) br.cond.dpnt skip_rbs_switch
+        mov r16=ar.bsp          // get existing backing store pointer
+#else
         ld8.fill r3=[r16]
 (pUStk) st1 [r18]=r17           // restore current->thread.on_ustack
         shr.u r18=r19,16        // get byte size of existing "dirty" partition
@@ -954,6 +1018,7 @@ GLOBAL_ENTRY(ia64_leave_kernel)
         mov r16=ar.bsp          // get existing backing store pointer
         LOAD_PHYS_STACK_REG_SIZE(r17)
 (pKStk) br.cond.dpnt skip_rbs_switch
+#endif
 
         /*
          * Restore user backing store.
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S
index 44841971f077..c932d86e2d81 100644
--- a/arch/ia64/kernel/fsys.S
+++ b/arch/ia64/kernel/fsys.S
@@ -660,7 +660,11 @@ GLOBAL_ENTRY(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
+        mov.m r30=ar.itc                        // M    get cycle for accounting
+#else
         nop.m 0
+#endif
         nop.i 0
         ;;
         mov r23=ar.bspstore                     // M2 (12 cyc) save ar.bspstore
@@ -682,6 +686,28 @@ GLOBAL_ENTRY(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
+        // 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
+        ;;
+        ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP   // time at last check in kernel
+        ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE   // time at leave kernel
+        ;;
+        ld8 r20=[r16],TI_AC_STAMP-TI_AC_STIME   // cumulated stime
+        ld8 r21=[r17]                           // cumulated utime
+        sub r22=r19,r18                         // stime before leave kernel
+        ;;
+        st8 [r16]=r30,TI_AC_STIME-TI_AC_STAMP   // update stamp
+        sub r18=r30,r19                         // elapsed time in user mode
+        ;;
+        add r20=r20,r22                         // sum stime
+        add r21=r21,r18                         // sum utime
+        ;;
+        st8 [r16]=r20                           // update stime
+        st8 [r17]=r21                           // update utime
+        ;;
+#endif
         mov ar.rsc=0x3                          // M2   set eager mode, pl 0, LE, loadrs=0
         mov rp=r14                              // I0   set the real return addr
         and r3=_TIF_SYSCALL_TRACEAUDIT,r3       // A
diff --git a/arch/ia64/kernel/head.S b/arch/ia64/kernel/head.S
index d3a41d5f8d12..ddeab4e36fd5 100644
--- a/arch/ia64/kernel/head.S
+++ b/arch/ia64/kernel/head.S
@@ -1002,6 +1002,26 @@ GLOBAL_ENTRY(sched_clock)
         br.ret.sptk.many rp
 END(sched_clock)
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+GLOBAL_ENTRY(cycle_to_cputime)
+        alloc r16=ar.pfs,1,0,0,0
+        addl r8=THIS_CPU(cpu_info) + IA64_CPUINFO_NSEC_PER_CYC_OFFSET,r0
+        ;;
+        ldf8 f8=[r8]
+        ;;
+        setf.sig f9=r32
+        ;;
+        xmpy.lu f10=f9,f8       // calculate low 64 bits of 128-bit product     (4 cyc)
+        xmpy.hu f11=f9,f8       // calculate high 64 bits of 128-bit product
+        ;;
+        getf.sig r8=f10         //                                              (5 cyc)
+        getf.sig r9=f11
+        ;;
+        shrp r8=r9,r8,IA64_NSEC_PER_CYC_SHIFT
+        br.ret.sptk.many rp
+END(cycle_to_cputime)
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+
 GLOBAL_ENTRY(start_kernel_thread)
         .prologue
         .save rp, r0                            // this is the end of the call-chain
diff --git a/arch/ia64/kernel/ivt.S b/arch/ia64/kernel/ivt.S
index 34f44d8be00d..6678c49daba3 100644
--- a/arch/ia64/kernel/ivt.S
+++ b/arch/ia64/kernel/ivt.S
@@ -805,8 +805,13 @@ 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
+        ;;
+        mov b6=r30                              // I0   setup syscall handler branch reg early
+#else
         nop.i 0
         ;;
+#endif
 
         mov.m r25=ar.unat                       // M2 (5 cyc)
         dep r29=r8,r29,41,2                     // I0   insert new ei into cr.ipsr
@@ -817,7 +822,11 @@ ENTRY(break_fault)
         //
 ///////////////////////////////////////////////////////////////////////
         st1 [r16]=r0                            // M2|3 clear current->thread.on_ustack flag
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+        mov.m r30=ar.itc                        // M    get cycle for accounting
+#else
         mov b6=r30                              // I0   setup syscall handler branch reg early
+#endif
         cmp.eq pKStk,pUStk=r0,r17               // A    were we on kernel stacks already?
 
         and r9=_TIF_SYSCALL_TRACEAUDIT,r9       // A    mask trace or audit
@@ -829,6 +838,30 @@ 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
+        // 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
+(pKStk) br.cond.spnt .skip_accounting           // B    unlikely skip
+        ;;
+        ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP   // M  get last stamp
+        ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE   // M  time at leave
+        ;;
+        ld8 r20=[r16],TI_AC_STAMP-TI_AC_STIME   // M  cumulated stime
+        ld8 r21=[r17]                           // M  cumulated utime
+        sub r22=r19,r18                         // A  stime before leave
+        ;;
+        st8 [r16]=r30,TI_AC_STIME-TI_AC_STAMP   // M  update stamp
+        sub r18=r30,r19                         // A  elapsed time in user
+        ;;
+        add r20=r20,r22                         // A  sum stime
+        add r21=r21,r18                         // A  sum utime
+        ;;
+        st8 [r16]=r20                           // M  update stime
+        st8 [r17]=r21                           // M  update utime
+        ;;
+.skip_accounting:
+#endif
         mov ar.rsc=0x3                          // M2   set eager mode, pl 0, LE, loadrs=0
         nop 0
         bsw.1                                   // B (6 cyc) regs are saved, switch to bank 1
@@ -928,6 +961,7 @@ END(interrupt)
          *      - r27: saved ar.rsc
          *      - r28: saved cr.iip
          *      - r29: saved cr.ipsr
+         *      - r30: ar.itc for accounting (don't touch)
          *      - r31: saved pr
          *      -  b0: original contents (to be saved)
          * On exit:
@@ -1090,6 +1124,41 @@ END(dispatch_illegal_op_fault)
         DBG_FAULT(16)
         FAULT(16)
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+        /*
+         * 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.
+         * If this fault ever gets "unreserved", simply moved the following
+         * code to a more suitable spot...
+         *
+         * account_sys_enter is called from SAVE_MIN* macros if accounting is
+         * enabled and if the macro is entered from user mode.
+         */
+ENTRY(account_sys_enter)
+        // mov.m r20=ar.itc is called in advance, and r13 is current
+        add r16=TI_AC_STAMP+IA64_TASK_SIZE,r13
+        add r17=TI_AC_LEAVE+IA64_TASK_SIZE,r13
+        ;;
+        ld8 r18=[r16],TI_AC_STIME-TI_AC_STAMP   // time at last check in kernel
+        ld8 r19=[r17],TI_AC_UTIME-TI_AC_LEAVE   // time at left from kernel
+        ;;
+        ld8 r23=[r16],TI_AC_STAMP-TI_AC_STIME   // cumulated stime
+        ld8 r21=[r17]                           // cumulated utime
+        sub r22=r19,r18                         // stime before leave kernel
+        ;;
+        st8 [r16]=r20,TI_AC_STIME-TI_AC_STAMP   // update stamp
+        sub r18=r20,r19                         // elapsed time in user mode
+        ;;
+        add r23=r23,r22                         // sum stime
+        add r21=r21,r18                         // sum utime
+        ;;
+        st8 [r16]=r23                           // update stime
+        st8 [r17]=r21                           // update utime
+        ;;
+        br.ret.sptk.many rp
+END(account_sys_enter)
+#endif
+
         .org ia64_ivt+0x4400
 /////////////////////////////////////////////////////////////////////////////////////////
 // 0x4400 Entry 17 (size 64 bundles) Reserved
diff --git a/arch/ia64/kernel/minstate.h b/arch/ia64/kernel/minstate.h
index c9ac8bada786..7c548ac52bbc 100644
--- a/arch/ia64/kernel/minstate.h
+++ b/arch/ia64/kernel/minstate.h
@@ -3,6 +3,18 @@
 
 #include "entry.h"
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+/* read ar.itc in advance, and use it before leaving bank 0 */
+#define ACCOUNT_GET_STAMP                               \
+(pUStk) mov.m r20=ar.itc;
+#define ACCOUNT_SYS_ENTER                               \
+(pUStk) br.call.spnt rp=account_sys_enter               \
+        ;;
+#else
+#define ACCOUNT_GET_STAMP
+#define ACCOUNT_SYS_ENTER
+#endif
+
 /*
  * DO_SAVE_MIN switches to the kernel stacks (if necessary) and saves
  * the minimum state necessary that allows us to turn psr.ic back
@@ -122,11 +134,13 @@
         ;;                                                                                      \
 .mem.offset 0,0; st8.spill [r16]=r2,16;                                                         \
 .mem.offset 8,0; st8.spill [r17]=r3,16;                                                         \
+        ACCOUNT_GET_STAMP                                                                       \
         adds r2=IA64_PT_REGS_R16_OFFSET,r1;                                                     \
         ;;                                                                                      \
         EXTRA;                                                                                  \
         movl r1=__gp;           /* establish kernel global pointer */                           \
         ;;                                                                                      \
+        ACCOUNT_SYS_ENTER                                                                       \
         bsw.1;                  /* switch back to bank 1 (must be last in insn group) */        \
         ;;
 
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 17fda5293c67..48e15a51782f 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -59,6 +59,84 @@ static struct clocksource clocksource_itc = {
 };
 static struct clocksource *itc_clocksource;
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+
+#include <linux/kernel_stat.h>
+
+extern cputime_t cycle_to_cputime(u64 cyc);
+
+/*
+ * Called from the context switch with interrupts disabled, to charge all
+ * accumulated times to the current process, and to prepare accounting on
+ * the next process.
+ */
+void ia64_account_on_switch(struct task_struct *prev, struct task_struct *next)
+{
+        struct thread_info *pi = task_thread_info(prev);
+        struct thread_info *ni = task_thread_info(next);
+        cputime_t delta_stime, delta_utime;
+        __u64 now;
+
+        now = ia64_get_itc();
+
+        delta_stime = cycle_to_cputime(pi->ac_stime + (now - pi->ac_stamp));
+        account_system_time(prev, 0, delta_stime);
+        account_system_time_scaled(prev, delta_stime);
+
+        if (pi->ac_utime) {
+                delta_utime = cycle_to_cputime(pi->ac_utime);
+                account_user_time(prev, delta_utime);
+                account_user_time_scaled(prev, delta_utime);
+        }
+
+        pi->ac_stamp = ni->ac_stamp = now;
+        ni->ac_stime = ni->ac_utime = 0;
+}
+
+/*
+ * Account time for a transition between system, hard irq or soft irq state.
+ * Note that this function is called with interrupts enabled.
+ */
+void account_system_vtime(struct task_struct *tsk)
+{
+        struct thread_info *ti = task_thread_info(tsk);
+        unsigned long flags;
+        cputime_t delta_stime;
+        __u64 now;
+
+        local_irq_save(flags);
+
+        now = ia64_get_itc();
+
+        delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
+        account_system_time(tsk, 0, delta_stime);
+        account_system_time_scaled(tsk, delta_stime);
+        ti->ac_stime = 0;
+
+        ti->ac_stamp = now;
+
+        local_irq_restore(flags);
+}
+
+/*
+ * Called from the timer interrupt handler to charge accumulated user time
+ * to the current process.  Must be called with interrupts disabled.
+ */
+void account_process_tick(struct task_struct *p, int user_tick)
+{
+        struct thread_info *ti = task_thread_info(p);
+        cputime_t delta_utime;
+
+        if (ti->ac_utime) {
+                delta_utime = cycle_to_cputime(ti->ac_utime);
+                account_user_time(p, delta_utime);
+                account_user_time_scaled(p, delta_utime);
+                ti->ac_utime = 0;
+        }
+}
+
+#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
+
 static irqreturn_t
 timer_interrupt (int irq, void *dev_id)
 {