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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-11-15 17:14:39 +0100
committerIngo Molnar <mingo@elte.hu>2011-11-17 12:20:22 +0100
commit391e43da797a96aeb65410281891f6d0b0e9611c (patch)
tree0ce6784525a5a8f75b377170cf1a7d60abccea29 /kernel/sched_clock.c
parent029632fbb7b7c9d85063cc9eb470de6c54873df3 (diff)
downloadop-kernel-dev-391e43da797a96aeb65410281891f6d0b0e9611c.zip
op-kernel-dev-391e43da797a96aeb65410281891f6d0b0e9611c.tar.gz
sched: Move all scheduler bits into kernel/sched/
There's too many sched*.[ch] files in kernel/, give them their own directory. (No code changed, other than Makefile glue added.) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_clock.c')
-rw-r--r--kernel/sched_clock.c350
1 files changed, 0 insertions, 350 deletions
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
deleted file mode 100644
index c685e31..0000000
--- a/kernel/sched_clock.c
+++ /dev/null
@@ -1,350 +0,0 @@
-/*
- * sched_clock for unstable cpu clocks
- *
- * Copyright (C) 2008 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
- *
- * Updates and enhancements:
- * Copyright (C) 2008 Red Hat, Inc. Steven Rostedt <srostedt@redhat.com>
- *
- * Based on code by:
- * Ingo Molnar <mingo@redhat.com>
- * Guillaume Chazarain <guichaz@gmail.com>
- *
- *
- * What:
- *
- * cpu_clock(i) provides a fast (execution time) high resolution
- * clock with bounded drift between CPUs. The value of cpu_clock(i)
- * is monotonic for constant i. The timestamp returned is in nanoseconds.
- *
- * ######################### BIG FAT WARNING ##########################
- * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
- * # go backwards !! #
- * ####################################################################
- *
- * There is no strict promise about the base, although it tends to start
- * at 0 on boot (but people really shouldn't rely on that).
- *
- * cpu_clock(i) -- can be used from any context, including NMI.
- * sched_clock_cpu(i) -- must be used with local IRQs disabled (implied by NMI)
- * local_clock() -- is cpu_clock() on the current cpu.
- *
- * How:
- *
- * The implementation either uses sched_clock() when
- * !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK, which means in that case the
- * sched_clock() is assumed to provide these properties (mostly it means
- * the architecture provides a globally synchronized highres time source).
- *
- * Otherwise it tries to create a semi stable clock from a mixture of other
- * clocks, including:
- *
- * - GTOD (clock monotomic)
- * - sched_clock()
- * - explicit idle events
- *
- * We use GTOD as base and use sched_clock() deltas to improve resolution. The
- * deltas are filtered to provide monotonicity and keeping it within an
- * expected window.
- *
- * Furthermore, explicit sleep and wakeup hooks allow us to account for time
- * that is otherwise invisible (TSC gets stopped).
- *
- *
- * Notes:
- *
- * The !IRQ-safetly of sched_clock() and sched_clock_cpu() comes from things
- * like cpufreq interrupts that can change the base clock (TSC) multiplier
- * and cause funny jumps in time -- although the filtering provided by
- * sched_clock_cpu() should mitigate serious artifacts we cannot rely on it
- * in general since for !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK we fully rely on
- * sched_clock().
- */
-#include <linux/spinlock.h>
-#include <linux/hardirq.h>
-#include <linux/export.h>
-#include <linux/percpu.h>
-#include <linux/ktime.h>
-#include <linux/sched.h>
-
-/*
- * Scheduler clock - returns current time in nanosec units.
- * This is default implementation.
- * Architectures and sub-architectures can override this.
- */
-unsigned long long __attribute__((weak)) sched_clock(void)
-{
- return (unsigned long long)(jiffies - INITIAL_JIFFIES)
- * (NSEC_PER_SEC / HZ);
-}
-EXPORT_SYMBOL_GPL(sched_clock);
-
-__read_mostly int sched_clock_running;
-
-#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
-__read_mostly int sched_clock_stable;
-
-struct sched_clock_data {
- u64 tick_raw;
- u64 tick_gtod;
- u64 clock;
-};
-
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct sched_clock_data, sched_clock_data);
-
-static inline struct sched_clock_data *this_scd(void)
-{
- return &__get_cpu_var(sched_clock_data);
-}
-
-static inline struct sched_clock_data *cpu_sdc(int cpu)
-{
- return &per_cpu(sched_clock_data, cpu);
-}
-
-void sched_clock_init(void)
-{
- u64 ktime_now = ktime_to_ns(ktime_get());
- int cpu;
-
- for_each_possible_cpu(cpu) {
- struct sched_clock_data *scd = cpu_sdc(cpu);
-
- scd->tick_raw = 0;
- scd->tick_gtod = ktime_now;
- scd->clock = ktime_now;
- }
-
- sched_clock_running = 1;
-}
-
-/*
- * min, max except they take wrapping into account
- */
-
-static inline u64 wrap_min(u64 x, u64 y)
-{
- return (s64)(x - y) < 0 ? x : y;
-}
-
-static inline u64 wrap_max(u64 x, u64 y)
-{
- return (s64)(x - y) > 0 ? x : y;
-}
-
-/*
- * update the percpu scd from the raw @now value
- *
- * - filter out backward motion
- * - use the GTOD tick value to create a window to filter crazy TSC values
- */
-static u64 sched_clock_local(struct sched_clock_data *scd)
-{
- u64 now, clock, old_clock, min_clock, max_clock;
- s64 delta;
-
-again:
- now = sched_clock();
- delta = now - scd->tick_raw;
- if (unlikely(delta < 0))
- delta = 0;
-
- old_clock = scd->clock;
-
- /*
- * scd->clock = clamp(scd->tick_gtod + delta,
- * max(scd->tick_gtod, scd->clock),
- * scd->tick_gtod + TICK_NSEC);
- */
-
- clock = scd->tick_gtod + delta;
- min_clock = wrap_max(scd->tick_gtod, old_clock);
- max_clock = wrap_max(old_clock, scd->tick_gtod + TICK_NSEC);
-
- clock = wrap_max(clock, min_clock);
- clock = wrap_min(clock, max_clock);
-
- if (cmpxchg64(&scd->clock, old_clock, clock) != old_clock)
- goto again;
-
- return clock;
-}
-
-static u64 sched_clock_remote(struct sched_clock_data *scd)
-{
- struct sched_clock_data *my_scd = this_scd();
- u64 this_clock, remote_clock;
- u64 *ptr, old_val, val;
-
- sched_clock_local(my_scd);
-again:
- this_clock = my_scd->clock;
- remote_clock = scd->clock;
-
- /*
- * Use the opportunity that we have both locks
- * taken to couple the two clocks: we take the
- * larger time as the latest time for both
- * runqueues. (this creates monotonic movement)
- */
- if (likely((s64)(remote_clock - this_clock) < 0)) {
- ptr = &scd->clock;
- old_val = remote_clock;
- val = this_clock;
- } else {
- /*
- * Should be rare, but possible:
- */
- ptr = &my_scd->clock;
- old_val = this_clock;
- val = remote_clock;
- }
-
- if (cmpxchg64(ptr, old_val, val) != old_val)
- goto again;
-
- return val;
-}
-
-/*
- * Similar to cpu_clock(), but requires local IRQs to be disabled.
- *
- * See cpu_clock().
- */
-u64 sched_clock_cpu(int cpu)
-{
- struct sched_clock_data *scd;
- u64 clock;
-
- WARN_ON_ONCE(!irqs_disabled());
-
- if (sched_clock_stable)
- return sched_clock();
-
- if (unlikely(!sched_clock_running))
- return 0ull;
-
- scd = cpu_sdc(cpu);
-
- if (cpu != smp_processor_id())
- clock = sched_clock_remote(scd);
- else
- clock = sched_clock_local(scd);
-
- return clock;
-}
-
-void sched_clock_tick(void)
-{
- struct sched_clock_data *scd;
- u64 now, now_gtod;
-
- if (sched_clock_stable)
- return;
-
- if (unlikely(!sched_clock_running))
- return;
-
- WARN_ON_ONCE(!irqs_disabled());
-
- scd = this_scd();
- now_gtod = ktime_to_ns(ktime_get());
- now = sched_clock();
-
- scd->tick_raw = now;
- scd->tick_gtod = now_gtod;
- sched_clock_local(scd);
-}
-
-/*
- * We are going deep-idle (irqs are disabled):
- */
-void sched_clock_idle_sleep_event(void)
-{
- sched_clock_cpu(smp_processor_id());
-}
-EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
-
-/*
- * We just idled delta nanoseconds (called with irqs disabled):
- */
-void sched_clock_idle_wakeup_event(u64 delta_ns)
-{
- if (timekeeping_suspended)
- return;
-
- sched_clock_tick();
- touch_softlockup_watchdog();
-}
-EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
-
-/*
- * As outlined at the top, provides a fast, high resolution, nanosecond
- * time source that is monotonic per cpu argument and has bounded drift
- * between cpus.
- *
- * ######################### BIG FAT WARNING ##########################
- * # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
- * # go backwards !! #
- * ####################################################################
- */
-u64 cpu_clock(int cpu)
-{
- u64 clock;
- unsigned long flags;
-
- local_irq_save(flags);
- clock = sched_clock_cpu(cpu);
- local_irq_restore(flags);
-
- return clock;
-}
-
-/*
- * Similar to cpu_clock() for the current cpu. Time will only be observed
- * to be monotonic if care is taken to only compare timestampt taken on the
- * same CPU.
- *
- * See cpu_clock().
- */
-u64 local_clock(void)
-{
- u64 clock;
- unsigned long flags;
-
- local_irq_save(flags);
- clock = sched_clock_cpu(smp_processor_id());
- local_irq_restore(flags);
-
- return clock;
-}
-
-#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
-
-void sched_clock_init(void)
-{
- sched_clock_running = 1;
-}
-
-u64 sched_clock_cpu(int cpu)
-{
- if (unlikely(!sched_clock_running))
- return 0;
-
- return sched_clock();
-}
-
-u64 cpu_clock(int cpu)
-{
- return sched_clock_cpu(cpu);
-}
-
-u64 local_clock(void)
-{
- return sched_clock_cpu(0);
-}
-
-#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
-
-EXPORT_SYMBOL_GPL(cpu_clock);
-EXPORT_SYMBOL_GPL(local_clock);
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