Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

Pull NOHZ updates from Ingo Molnar:
 "The main changes, mostly written by Frederic Weisbecker, include:

   - Fix some jiffies based cputime assumptions.  (No real harm because
     the concerned code isn't used by full dynticks.)

   - Simplify jiffies <-> usecs conversions.  Remove dead code.

   - Remove early hacks on nohz full code that avoided messing up idle
     nohz internals.  Now nohz integrates well full and idle and such
     hack have become needless.

   - Restart nohz full tick from irq exit.  (A simplification and a
     preparation for future optimization on scheduler kick to nohz
     full)

   - Code cleanups.

   - Tile driver isolation enhancement on top of nohz.  (Chris Metcalf)"

* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  nohz: Remove useless argument on tick_nohz_task_switch()
  nohz: Move tick_nohz_restart_sched_tick() above its users
  nohz: Restart nohz full tick from irq exit
  nohz: Remove idle task special case
  nohz: Prevent tilegx network driver interrupts
  alpha: Fix jiffies based cputime assumption
  apm32: Fix cputime == jiffies assumption
  jiffies: Remove HZ > USEC_PER_SEC special case

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 36dc91ace83ae97069df82f5e3923a24275c6a9b..6cc08166ff00d0f616b3a10146014e3ca4453d4b 100644 (file)
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -1138,6 +1138,7 @@ SYSCALL_DEFINE2(osf_getrusage, int, who, struct rusage32 __user *, ru)
 {
        struct rusage32 r;
        cputime_t utime, stime;
+       unsigned long utime_jiffies, stime_jiffies;
 
        if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
                return -EINVAL;
@@ -1146,14 +1147,18 @@ SYSCALL_DEFINE2(osf_getrusage, int, who, struct rusage32 __user *, ru)
        switch (who) {
        case RUSAGE_SELF:
                task_cputime(current, &utime, &stime);
-               jiffies_to_timeval32(utime, &r.ru_utime);
-               jiffies_to_timeval32(stime, &r.ru_stime);
+               utime_jiffies = cputime_to_jiffies(utime);
+               stime_jiffies = cputime_to_jiffies(stime);
+               jiffies_to_timeval32(utime_jiffies, &r.ru_utime);
+               jiffies_to_timeval32(stime_jiffies, &r.ru_stime);
                r.ru_minflt = current->min_flt;
                r.ru_majflt = current->maj_flt;
                break;
        case RUSAGE_CHILDREN:
-               jiffies_to_timeval32(current->signal->cutime, &r.ru_utime);
-               jiffies_to_timeval32(current->signal->cstime, &r.ru_stime);
+               utime_jiffies = cputime_to_jiffies(current->signal->cutime);
+               stime_jiffies = cputime_to_jiffies(current->signal->cstime);
+               jiffies_to_timeval32(utime_jiffies, &r.ru_utime);
+               jiffies_to_timeval32(stime_jiffies, &r.ru_stime);
                r.ru_minflt = current->signal->cmin_flt;
                r.ru_majflt = current->signal->cmaj_flt;
                break;

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 927ec923594798bda4d5a4dff74cfbe577ad540f..052c9c3026cce69ff68aaf9f0a3b5fd4a8c2cadf 100644 (file)
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -919,7 +919,7 @@ recalc:
        } else if (jiffies_since_last_check > idle_period) {
                unsigned int idle_percentage;
 
-               idle_percentage = stime - last_stime;
+               idle_percentage = cputime_to_jiffies(stime - last_stime);
                idle_percentage *= 100;
                idle_percentage /= jiffies_since_last_check;
                use_apm_idle = (idle_percentage > idle_threshold);

diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c
index a3f7610002aa12269bfa2953463d3da680e3bfa6..0a15acc075b3abfac4ce3ac5eed3f1bbf1f0f76e 100644 (file)
--- a/drivers/net/ethernet/tile/tilegx.c
+++ b/drivers/net/ethernet/tile/tilegx.c
@@ -40,6 +40,7 @@
 #include <linux/tcp.h>
 #include <linux/net_tstamp.h>
 #include <linux/ptp_clock_kernel.h>
+#include <linux/tick.h>
 
 #include <asm/checksum.h>
 #include <asm/homecache.h>
@@ -2273,7 +2274,8 @@ static int __init tile_net_init_module(void)
                tile_net_dev_init(name, mac);
 
        if (!network_cpus_init())
-               network_cpus_map = *cpu_online_mask;
+               cpumask_and(&network_cpus_map, housekeeping_cpumask(),
+                           cpu_online_mask);
 
        return 0;
 }

diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 1ba48a18c1d77e9fbc497a3f01cdd58bc15459f8..9ea50da7351351e6165326687ac959ab09a52cac 100644 (file)
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -363,18 +363,11 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
 }
 
 extern unsigned long __usecs_to_jiffies(const unsigned int u);
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
+#if !(USEC_PER_SEC % HZ)
 static inline unsigned long _usecs_to_jiffies(const unsigned int u)
 {
        return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ);
 }
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
-static inline unsigned long _usecs_to_jiffies(const unsigned int u)
-{
-       return u * (HZ / USEC_PER_SEC);
-}
-static inline unsigned long _usecs_to_jiffies(const unsigned int u)
-{
 #else
 static inline unsigned long _usecs_to_jiffies(const unsigned int u)
 {

diff --git a/include/linux/tick.h b/include/linux/tick.h
index edbfc9a5293ee48f981952eb709f0ed13e6b07c8..48d901f83f92e4cf78bc932d94142b4594d65d9d 100644 (file)
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -147,22 +147,29 @@ static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask)
                cpumask_or(mask, mask, tick_nohz_full_mask);
 }
 
-extern void __tick_nohz_full_check(void);
 extern void tick_nohz_full_kick(void);
 extern void tick_nohz_full_kick_cpu(int cpu);
 extern void tick_nohz_full_kick_all(void);
-extern void __tick_nohz_task_switch(struct task_struct *tsk);
+extern void __tick_nohz_task_switch(void);
 #else
 static inline bool tick_nohz_full_enabled(void) { return false; }
 static inline bool tick_nohz_full_cpu(int cpu) { return false; }
 static inline void tick_nohz_full_add_cpus_to(struct cpumask *mask) { }
-static inline void __tick_nohz_full_check(void) { }
 static inline void tick_nohz_full_kick_cpu(int cpu) { }
 static inline void tick_nohz_full_kick(void) { }
 static inline void tick_nohz_full_kick_all(void) { }
-static inline void __tick_nohz_task_switch(struct task_struct *tsk) { }
+static inline void __tick_nohz_task_switch(void) { }
 #endif
 
+static inline const struct cpumask *housekeeping_cpumask(void)
+{
+#ifdef CONFIG_NO_HZ_FULL
+       if (tick_nohz_full_enabled())
+               return housekeeping_mask;
+#endif
+       return cpu_possible_mask;
+}
+
 static inline bool is_housekeeping_cpu(int cpu)
 {
 #ifdef CONFIG_NO_HZ_FULL
@@ -181,16 +188,10 @@ static inline void housekeeping_affine(struct task_struct *t)
 #endif
 }
 
-static inline void tick_nohz_full_check(void)
-{
-       if (tick_nohz_full_enabled())
-               __tick_nohz_full_check();
-}
-
-static inline void tick_nohz_task_switch(struct task_struct *tsk)
+static inline void tick_nohz_task_switch(void)
 {
        if (tick_nohz_full_enabled())
-               __tick_nohz_task_switch(tsk);
+               __tick_nohz_task_switch();
 }
 
 #endif

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7819725e9da88f203eeb81446c6892543b40b696..8b864ecee0e187c58a7903058ae1c0fa57b4d0c3 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2543,7 +2543,7 @@ static struct rq *finish_task_switch(struct task_struct *prev)
                put_task_struct(prev);
        }
 
-       tick_nohz_task_switch(current);
+       tick_nohz_task_switch();
        return rq;
 }
 

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index c792429e98c6de3ffb75f95f745d6cca9724585b..3319e16f31e58ed69534ab2fa7e5cd05d7b90d8f 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -197,27 +197,9 @@ static bool can_stop_full_tick(void)
        return true;
 }
 
-static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now);
-
-/*
- * Re-evaluate the need for the tick on the current CPU
- * and restart it if necessary.
- */
-void __tick_nohz_full_check(void)
-{
-       struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
-
-       if (tick_nohz_full_cpu(smp_processor_id())) {
-               if (ts->tick_stopped && !is_idle_task(current)) {
-                       if (!can_stop_full_tick())
-                               tick_nohz_restart_sched_tick(ts, ktime_get());
-               }
-       }
-}
-
 static void nohz_full_kick_work_func(struct irq_work *work)
 {
-       __tick_nohz_full_check();
+       /* Empty, the tick restart happens on tick_nohz_irq_exit() */
 }
 
 static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = {
@@ -252,7 +234,7 @@ void tick_nohz_full_kick_cpu(int cpu)
 
 static void nohz_full_kick_ipi(void *info)
 {
-       __tick_nohz_full_check();
+       /* Empty, the tick restart happens on tick_nohz_irq_exit() */
 }
 
 /*
@@ -276,7 +258,7 @@ void tick_nohz_full_kick_all(void)
  * It might need the tick due to per task/process properties:
  * perf events, posix cpu timers, ...
  */
-void __tick_nohz_task_switch(struct task_struct *tsk)
+void __tick_nohz_task_switch(void)
 {
        unsigned long flags;
 
@@ -705,21 +687,38 @@ out:
        return tick;
 }
 
-static void tick_nohz_full_stop_tick(struct tick_sched *ts)
+static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
+{
+       /* Update jiffies first */
+       tick_do_update_jiffies64(now);
+       update_cpu_load_nohz();
+
+       calc_load_exit_idle();
+       touch_softlockup_watchdog();
+       /*
+        * Cancel the scheduled timer and restore the tick
+        */
+       ts->tick_stopped  = 0;
+       ts->idle_exittime = now;
+
+       tick_nohz_restart(ts, now);
+}
+
+static void tick_nohz_full_update_tick(struct tick_sched *ts)
 {
 #ifdef CONFIG_NO_HZ_FULL
        int cpu = smp_processor_id();
 
-       if (!tick_nohz_full_cpu(cpu) || is_idle_task(current))
+       if (!tick_nohz_full_cpu(cpu))
                return;
 
        if (!ts->tick_stopped && ts->nohz_mode == NOHZ_MODE_INACTIVE)
                return;
 
-       if (!can_stop_full_tick())
-               return;
-
-       tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
+       if (can_stop_full_tick())
+               tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
+       else if (ts->tick_stopped)
+               tick_nohz_restart_sched_tick(ts, ktime_get());
 #endif
 }
 
@@ -849,7 +848,7 @@ void tick_nohz_irq_exit(void)
        if (ts->inidle)
                __tick_nohz_idle_enter(ts);
        else
-               tick_nohz_full_stop_tick(ts);
+               tick_nohz_full_update_tick(ts);
 }
 
 /**
@@ -864,23 +863,6 @@ ktime_t tick_nohz_get_sleep_length(void)
        return ts->sleep_length;
 }
 
-static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
-{
-       /* Update jiffies first */
-       tick_do_update_jiffies64(now);
-       update_cpu_load_nohz();
-
-       calc_load_exit_idle();
-       touch_softlockup_watchdog();
-       /*
-        * Cancel the scheduled timer and restore the tick
-        */
-       ts->tick_stopped  = 0;
-       ts->idle_exittime = now;
-
-       tick_nohz_restart(ts, now);
-}
-
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE

diff --git a/kernel/time/time.c b/kernel/time/time.c
index 85d5bb1d67ebc777e9dab638d3988b2fdaedf172..ad1bf23e6eb7c34eef6c2a6a893eabfaff565279 100644 (file)
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -268,10 +268,14 @@ EXPORT_SYMBOL(jiffies_to_msecs);
 
 unsigned int jiffies_to_usecs(const unsigned long j)
 {
-#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
+       /*
+        * Hz usually doesn't go much further MSEC_PER_SEC.
+        * jiffies_to_usecs() and usecs_to_jiffies() depend on that.
+        */
+       BUILD_BUG_ON(HZ > USEC_PER_SEC);
+
+#if !(USEC_PER_SEC % HZ)
        return (USEC_PER_SEC / HZ) * j;
-#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
-       return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
 #else
 # if BITS_PER_LONG == 32
        return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;