[RFC][PATCH 3/4] time: Parametrize all tk_fast_mono users

From: Peter Zijlstra
Date: Thu Mar 19 2015 - 05:38:25 EST


In preparation for more tk_fast instances, remove all hard-coded
tk_fast_mono references.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/time/timekeeping.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)

--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -364,18 +364,18 @@ static inline s64 timekeeping_get_ns(str
* slightly wrong timestamp (a few nanoseconds). See
* @ktime_get_mono_fast_ns.
*/
-static void update_fast_timekeeper(struct tk_read_base *tkr)
+static void update_fast_timekeeper(struct tk_read_base *tkr, struct tk_fast *tkf)
{
- struct tk_read_base *base = tk_fast_mono.base;
+ struct tk_read_base *base = tkf->base;

/* Force readers off to base[1] */
- raw_write_seqcount_latch(&tk_fast_mono.seq);
+ raw_write_seqcount_latch(&tkf->seq);

/* Update base[0] */
memcpy(base, tkr, sizeof(*base));

/* Force readers back to base[0] */
- raw_write_seqcount_latch(&tk_fast_mono.seq);
+ raw_write_seqcount_latch(&tkf->seq);

/* Update base[1] */
memcpy(base + 1, base, sizeof(*base));
@@ -413,20 +413,25 @@ static void update_fast_timekeeper(struc
* of the following timestamps. Callers need to be aware of that and
* deal with it.
*/
-u64 notrace ktime_get_mono_fast_ns(void)
+static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
{
struct tk_read_base *tkr;
unsigned int seq;
u64 now;

do {
- seq = raw_read_seqcount(&tk_fast_mono.seq);
- tkr = tk_fast_mono.base + (seq & 0x01);
+ seq = raw_read_seqcount(&tkf->seq);
+ tkr = tkf->base + (seq & 0x01);
now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr);
+ } while (read_seqcount_retry(&tkf->seq, seq));

- } while (read_seqcount_retry(&tk_fast_mono.seq, seq));
return now;
}
+
+u64 ktime_get_mono_fast_ns(void)
+{
+ return __ktime_get_fast_ns(&tk_fast_mono);
+}
EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);

/* Suspend-time cycles value for halted fast timekeeper. */
@@ -455,7 +460,7 @@ static void halt_fast_timekeeper(struct
memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
cycles_at_suspend = tkr->read(tkr->clock);
tkr_dummy.read = dummy_clock_read;
- update_fast_timekeeper(&tkr_dummy);
+ update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
}

#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
@@ -586,7 +591,7 @@ static void timekeeping_update(struct ti
memcpy(&shadow_timekeeper, &tk_core.timekeeper,
sizeof(tk_core.timekeeper));

- update_fast_timekeeper(&tk->tkr_mono);
+ update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
}

/**


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