[PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem)
Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390
timer interrupt handler with this change.
Currently update_times() calculates ticks by "jiffies - wall_jiffies", but
callers of do_timer() should know how many ticks to update. Passing ticks
get rid of this redundant calculation. Also there are another redundancy
pointed out by Martin Schwidefsky.
This cleanup make a barrier added by
5aee405c662ca644980c184774277fc6d0769a84 needless. So this patch removes
it.
As a bonus, this cleanup make wall_jiffies can be removed easily, since now
wall_jiffies is always synced with jiffies. (This patch does not really
remove wall_jiffies. It would be another cleanup patch)
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c
index b191cc7..7c1e444 100644
--- a/arch/alpha/kernel/time.c
+++ b/arch/alpha/kernel/time.c
@@ -132,7 +132,7 @@
nticks = delta >> FIX_SHIFT;
while (nticks > 0) {
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
index d4dceb5..f7d5165 100644
--- a/arch/arm/kernel/time.c
+++ b/arch/arm/kernel/time.c
@@ -337,7 +337,7 @@
profile_tick(CPU_PROFILING, regs);
do_leds();
do_set_rtc();
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/arm26/kernel/time.c b/arch/arm26/kernel/time.c
index db63d75..80adbd0 100644
--- a/arch/arm26/kernel/time.c
+++ b/arch/arm26/kernel/time.c
@@ -194,7 +194,7 @@
static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c
index b0e6b58..3e56b9f 100644
--- a/arch/avr32/kernel/time.c
+++ b/arch/avr32/kernel/time.c
@@ -148,7 +148,7 @@
* Call the generic timer interrupt handler
*/
write_seqlock(&xtime_lock);
- do_timer(regs);
+ do_timer(1);
write_sequnlock(&xtime_lock);
/*
diff --git a/arch/cris/arch-v10/kernel/time.c b/arch/cris/arch-v10/kernel/time.c
index 9c22b76..ebacf14 100644
--- a/arch/cris/arch-v10/kernel/time.c
+++ b/arch/cris/arch-v10/kernel/time.c
@@ -227,7 +227,7 @@
/* call the real timer interrupt handler */
- do_timer(regs);
+ do_timer(1);
cris_do_profile(regs); /* Save profiling information */
diff --git a/arch/cris/arch-v32/kernel/time.c b/arch/cris/arch-v32/kernel/time.c
index 50f3f93..be0a016 100644
--- a/arch/cris/arch-v32/kernel/time.c
+++ b/arch/cris/arch-v32/kernel/time.c
@@ -219,7 +219,7 @@
return IRQ_HANDLED;
/* call the real timer interrupt handler */
- do_timer(regs);
+ do_timer(1);
/*
* If we have an externally synchronized Linux clock, then update
diff --git a/arch/frv/kernel/time.c b/arch/frv/kernel/time.c
index 3d0284b..7e55884 100644
--- a/arch/frv/kernel/time.c
+++ b/arch/frv/kernel/time.c
@@ -70,7 +70,7 @@
*/
write_seqlock(&xtime_lock);
- do_timer(regs);
+ do_timer(1);
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING, regs);
diff --git a/arch/h8300/kernel/time.c b/arch/h8300/kernel/time.c
index 688a510..e569d17 100644
--- a/arch/h8300/kernel/time.c
+++ b/arch/h8300/kernel/time.c
@@ -41,7 +41,7 @@
/* may need to kick the hardware timer */
platform_timer_eoi();
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 6928ef0..16262687 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -78,7 +78,7 @@
* xtime_lock.
*/
write_seqlock(&xtime_lock);
- do_timer(regs);
+ do_timer(1);
local_cpu_data->itm_next = new_itm;
write_sequnlock(&xtime_lock);
} else
diff --git a/arch/m32r/kernel/time.c b/arch/m32r/kernel/time.c
index ded0be0..7a89689 100644
--- a/arch/m32r/kernel/time.c
+++ b/arch/m32r/kernel/time.c
@@ -202,7 +202,7 @@
#ifndef CONFIG_SMP
profile_tick(CPU_PROFILING, regs);
#endif
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
diff --git a/arch/m68k/kernel/time.c b/arch/m68k/kernel/time.c
index 98e4b1a..1072e49 100644
--- a/arch/m68k/kernel/time.c
+++ b/arch/m68k/kernel/time.c
@@ -40,7 +40,7 @@
*/
static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
{
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/m68k/sun3/sun3ints.c b/arch/m68k/sun3/sun3ints.c
index f18b9d3..dc4ea7e 100644
--- a/arch/m68k/sun3/sun3ints.c
+++ b/arch/m68k/sun3/sun3ints.c
@@ -65,7 +65,7 @@
#ifdef CONFIG_SUN3
intersil_clear();
#endif
- do_timer(fp);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(fp));
#endif
diff --git a/arch/m68knommu/kernel/time.c b/arch/m68knommu/kernel/time.c
index 1db9872..db1e1ce 100644
--- a/arch/m68knommu/kernel/time.c
+++ b/arch/m68knommu/kernel/time.c
@@ -51,7 +51,7 @@
write_seqlock(&xtime_lock);
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/mips/au1000/common/time.c b/arch/mips/au1000/common/time.c
index 7fbea1b..0a067f3 100644
--- a/arch/mips/au1000/common/time.c
+++ b/arch/mips/au1000/common/time.c
@@ -96,7 +96,7 @@
timerlo = count;
kstat_this_cpu.irqs[irq]++;
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
@@ -137,7 +137,7 @@
}
while (time_elapsed > 0) {
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
@@ -156,7 +156,7 @@
if (jiffie_drift >= 999) {
jiffie_drift -= 999;
- do_timer(regs); /* increment jiffies by one */
+ do_timer(1); /* increment jiffies by one */
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/mips/gt64120/common/time.c b/arch/mips/gt64120/common/time.c
index d837b26..7feca49 100644
--- a/arch/mips/gt64120/common/time.c
+++ b/arch/mips/gt64120/common/time.c
@@ -34,7 +34,7 @@
if (irq_src & 0x00000800) { /* Check for timer interrupt */
handled = 1;
irq_src &= ~0x00000800;
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c
index 170cb67..6ab8d97 100644
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -434,7 +434,7 @@
/*
* call the generic timer interrupt handling
*/
- do_timer(regs);
+ do_timer(1);
/*
* If we have an externally synchronized Linux clock, then update
diff --git a/arch/mips/momentum/ocelot_g/gt-irq.c b/arch/mips/momentum/ocelot_g/gt-irq.c
index 9fb2493..6cd87cf 100644
--- a/arch/mips/momentum/ocelot_g/gt-irq.c
+++ b/arch/mips/momentum/ocelot_g/gt-irq.c
@@ -133,7 +133,7 @@
MV_WRITE(TIMER_COUNTER_0_3_INTERRUPT_CAUSE, 0x0);
/* handle the timer call */
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/mips/sgi-ip27/ip27-timer.c b/arch/mips/sgi-ip27/ip27-timer.c
index b029ba7..c62a3a9 100644
--- a/arch/mips/sgi-ip27/ip27-timer.c
+++ b/arch/mips/sgi-ip27/ip27-timer.c
@@ -111,7 +111,7 @@
kstat_this_cpu.irqs[irq]++; /* kstat only for bootcpu? */
if (cpu == 0)
- do_timer(regs);
+ do_timer(1);
update_process_times(user_mode(regs));
diff --git a/arch/parisc/kernel/time.c b/arch/parisc/kernel/time.c
index 5facc9b..700df10 100644
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -79,7 +79,7 @@
#endif
if (cpu == 0) {
write_seqlock(&xtime_lock);
- do_timer(regs);
+ do_timer(1);
write_sequnlock(&xtime_lock);
}
}
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 7a3c3f79..71f71da 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -693,7 +693,7 @@
tb_next_jiffy = tb_last_jiffy + tb_ticks_per_jiffy;
if (per_cpu(last_jiffy, cpu) >= tb_next_jiffy) {
tb_last_jiffy = tb_next_jiffy;
- do_timer(regs);
+ do_timer(1);
timer_recalc_offset(tb_last_jiffy);
timer_check_rtc();
}
diff --git a/arch/ppc/kernel/time.c b/arch/ppc/kernel/time.c
index 6ab8cc7..1e1f315 100644
--- a/arch/ppc/kernel/time.c
+++ b/arch/ppc/kernel/time.c
@@ -153,7 +153,7 @@
/* We are in an interrupt, no need to save/restore flags */
write_seqlock(&xtime_lock);
tb_last_stamp = jiffy_stamp;
- do_timer(regs);
+ do_timer(1);
/*
* update the rtc when needed, this should be performed on the
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 1981c61..abab42e 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -166,7 +166,7 @@
void account_ticks(struct pt_regs *regs)
{
__u64 tmp;
- __u32 ticks, xticks;
+ __u32 ticks;
/* Calculate how many ticks have passed. */
if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer) {
@@ -204,6 +204,7 @@
*/
write_seqlock(&xtime_lock);
if (S390_lowcore.jiffy_timer > xtime_cc) {
+ __u32 xticks;
tmp = S390_lowcore.jiffy_timer - xtime_cc;
if (tmp >= 2*CLK_TICKS_PER_JIFFY) {
xticks = __div(tmp, CLK_TICKS_PER_JIFFY);
@@ -212,13 +213,11 @@
xticks = 1;
xtime_cc += CLK_TICKS_PER_JIFFY;
}
- while (xticks--)
- do_timer(regs);
+ do_timer(xticks);
}
write_sequnlock(&xtime_lock);
#else
- for (xticks = ticks; xticks > 0; xticks--)
- do_timer(regs);
+ do_timer(ticks);
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
diff --git a/arch/sh/kernel/time.c b/arch/sh/kernel/time.c
index 149d971..f664a19 100644
--- a/arch/sh/kernel/time.c
+++ b/arch/sh/kernel/time.c
@@ -117,7 +117,7 @@
*/
void handle_timer_tick(struct pt_regs *regs)
{
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/sh64/kernel/time.c b/arch/sh64/kernel/time.c
index b8162e5..3b61e06 100644
--- a/arch/sh64/kernel/time.c
+++ b/arch/sh64/kernel/time.c
@@ -298,7 +298,7 @@
asm ("getcon cr62, %0" : "=r" (current_ctc));
ctc_last_interrupt = (unsigned long) current_ctc;
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
index bfd31aa..e19b1ba 100644
--- a/arch/sparc/kernel/pcic.c
+++ b/arch/sparc/kernel/pcic.c
@@ -712,7 +712,7 @@
{
write_seqlock(&xtime_lock); /* Dummy, to show that we remember */
pcic_clear_clock_irq();
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/sparc/kernel/time.c b/arch/sparc/kernel/time.c
index 845081b0..6f84fa1 100644
--- a/arch/sparc/kernel/time.c
+++ b/arch/sparc/kernel/time.c
@@ -128,7 +128,7 @@
#endif
clear_clock_irq();
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/sparc64/kernel/time.c b/arch/sparc64/kernel/time.c
index b0b4fee..ca11934 100644
--- a/arch/sparc64/kernel/time.c
+++ b/arch/sparc64/kernel/time.c
@@ -465,7 +465,7 @@
profile_tick(CPU_PROFILING, regs);
update_process_times(user_mode(regs));
#endif
- do_timer(regs);
+ do_timer(1);
/* Guarantee that the following sequences execute
* uninterrupted.
@@ -496,7 +496,7 @@
{
write_seqlock(&xtime_lock);
- do_timer(regs);
+ do_timer(1);
timer_check_rtc();
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 820affb..a92965f 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -93,7 +93,7 @@
write_seqlock_irqsave(&xtime_lock, flags);
- do_timer(regs);
+ do_timer(1);
nsecs = get_time();
xtime.tv_sec = nsecs / NSEC_PER_SEC;
diff --git a/arch/v850/kernel/time.c b/arch/v850/kernel/time.c
index a0b4669..f4d1a4d 100644
--- a/arch/v850/kernel/time.c
+++ b/arch/v850/kernel/time.c
@@ -51,7 +51,7 @@
if (mach_tick)
mach_tick ();
- do_timer (regs);
+ do_timer (1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 1c255ee..7ea3bf2 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -415,16 +415,16 @@
(((long) offset << US_SCALE) / vxtime.tsc_quot) - 1;
}
- if (lost > 0) {
+ if (lost > 0)
handle_lost_ticks(lost, regs);
- jiffies += lost;
- }
+ else
+ lost = 0;
/*
* Do the timer stuff.
*/
- do_timer(regs);
+ do_timer(lost + 1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/arch/xtensa/kernel/time.c b/arch/xtensa/kernel/time.c
index 412ab32..241db20 100644
--- a/arch/xtensa/kernel/time.c
+++ b/arch/xtensa/kernel/time.c
@@ -175,7 +175,7 @@
last_ccount_stamp = next;
next += CCOUNT_PER_JIFFY;
- do_timer (regs); /* Linux handler in kernel/timer.c */
+ do_timer (1); /* Linux handler in kernel/timer.c */
if (ntp_synced() &&
xtime.tv_sec - last_rtc_update >= 659 &&
diff --git a/include/asm-arm/arch-clps711x/time.h b/include/asm-arm/arch-clps711x/time.h
index 9cb27cd..0e4a390 100644
--- a/include/asm-arm/arch-clps711x/time.h
+++ b/include/asm-arm/arch-clps711x/time.h
@@ -29,7 +29,7 @@
p720t_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
do_leds();
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/include/asm-arm/arch-l7200/time.h b/include/asm-arm/arch-l7200/time.h
index 7b98b53..c69cb50 100644
--- a/include/asm-arm/arch-l7200/time.h
+++ b/include/asm-arm/arch-l7200/time.h
@@ -45,7 +45,7 @@
static irqreturn_t
timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode(regs));
#endif
diff --git a/include/asm-i386/mach-default/do_timer.h b/include/asm-i386/mach-default/do_timer.h
index 6312c3e..4182c34 100644
--- a/include/asm-i386/mach-default/do_timer.h
+++ b/include/asm-i386/mach-default/do_timer.h
@@ -16,7 +16,7 @@
static inline void do_timer_interrupt_hook(struct pt_regs *regs)
{
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode_vm(regs));
#endif
diff --git a/include/asm-i386/mach-visws/do_timer.h b/include/asm-i386/mach-visws/do_timer.h
index 95568e6..8db618c5 100644
--- a/include/asm-i386/mach-visws/do_timer.h
+++ b/include/asm-i386/mach-visws/do_timer.h
@@ -9,7 +9,7 @@
/* Clear the interrupt */
co_cpu_write(CO_CPU_STAT,co_cpu_read(CO_CPU_STAT) & ~CO_STAT_TIMEINTR);
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode_vm(regs));
#endif
diff --git a/include/asm-i386/mach-voyager/do_timer.h b/include/asm-i386/mach-voyager/do_timer.h
index eaf5180..099fe9f 100644
--- a/include/asm-i386/mach-voyager/do_timer.h
+++ b/include/asm-i386/mach-voyager/do_timer.h
@@ -3,7 +3,7 @@
static inline void do_timer_interrupt_hook(struct pt_regs *regs)
{
- do_timer(regs);
+ do_timer(1);
#ifndef CONFIG_SMP
update_process_times(user_mode_vm(regs));
#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ed2af86..503dea6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1206,7 +1206,7 @@
#include <asm/current.h>
-extern void do_timer(struct pt_regs *);
+extern void do_timer(unsigned long ticks);
extern int FASTCALL(wake_up_state(struct task_struct * tsk, unsigned int state));
extern int FASTCALL(wake_up_process(struct task_struct * tsk));
diff --git a/kernel/timer.c b/kernel/timer.c
index a2cb1ec..4f55622 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1222,10 +1222,8 @@
unsigned long active_tasks; /* fixed-point */
static int count = LOAD_FREQ;
- count -= ticks;
- if (count < 0) {
- count += LOAD_FREQ;
- active_tasks = count_active_tasks();
+ active_tasks = count_active_tasks();
+ for (count -= ticks; count < 0; count += LOAD_FREQ) {
CALC_LOAD(avenrun[0], EXP_1, active_tasks);
CALC_LOAD(avenrun[1], EXP_5, active_tasks);
CALC_LOAD(avenrun[2], EXP_15, active_tasks);
@@ -1270,11 +1268,8 @@
* Called by the timer interrupt. xtime_lock must already be taken
* by the timer IRQ!
*/
-static inline void update_times(void)
+static inline void update_times(unsigned long ticks)
{
- unsigned long ticks;
-
- ticks = jiffies - wall_jiffies;
wall_jiffies += ticks;
update_wall_time();
calc_load(ticks);
@@ -1286,12 +1281,10 @@
* jiffies is defined in the linker script...
*/
-void do_timer(struct pt_regs *regs)
+void do_timer(unsigned long ticks)
{
- jiffies_64++;
- /* prevent loading jiffies before storing new jiffies_64 value. */
- barrier();
- update_times();
+ jiffies_64 += ticks;
+ update_times(ticks);
}
#ifdef __ARCH_WANT_SYS_ALARM
