diff options
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/Makefile | 2 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 29 | ||||
| -rw-r--r-- | kernel/time/timer.c | 3 |
3 files changed, 4 insertions, 30 deletions
diff --git a/kernel/time/Makefile b/kernel/time/Makefile index ffc4cc3dcd47..49eca0beed32 100644 --- a/kernel/time/Makefile +++ b/kernel/time/Makefile @@ -12,5 +12,3 @@ obj-$(CONFIG_TICK_ONESHOT) += tick-oneshot.o tick-sched.o obj-$(CONFIG_TIMER_STATS) += timer_stats.o obj-$(CONFIG_DEBUG_FS) += timekeeping_debug.o obj-$(CONFIG_TEST_UDELAY) += test_udelay.o - -$(obj)/time.o: $(objtree)/include/config/ diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 30b7a409bf1e..bca3667a2de1 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -319,32 +319,7 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr) * We want to use this from any context including NMI and tracing / * instrumenting the timekeeping code itself. * - * So we handle this differently than the other timekeeping accessor - * functions which retry when the sequence count has changed. The - * update side does: - * - * smp_wmb(); <- Ensure that the last base[1] update is visible - * tkf->seq++; - * smp_wmb(); <- Ensure that the seqcount update is visible - * update(tkf->base[0], tkr); - * smp_wmb(); <- Ensure that the base[0] update is visible - * tkf->seq++; - * smp_wmb(); <- Ensure that the seqcount update is visible - * update(tkf->base[1], tkr); - * - * The reader side does: - * - * do { - * seq = tkf->seq; - * smp_rmb(); - * idx = seq & 0x01; - * now = now(tkf->base[idx]); - * smp_rmb(); - * } while (seq != tkf->seq) - * - * As long as we update base[0] readers are forced off to - * base[1]. Once base[0] is updated readers are redirected to base[0] - * and the base[1] update takes place. + * Employ the latch technique; see @raw_write_seqcount_latch. * * So if a NMI hits the update of base[0] then it will use base[1] * which is still consistent. In the worst case this can result is a @@ -407,7 +382,7 @@ static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf) u64 now; do { - seq = raw_read_seqcount(&tkf->seq); + seq = raw_read_seqcount_latch(&tkf->seq); tkr = tkf->base + (seq & 0x01); now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr); } while (read_seqcount_retry(&tkf->seq, seq)); diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 520499dd85af..5e097fa9faf7 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1566,7 +1566,7 @@ static void migrate_timers(int cpu) BUG_ON(cpu_online(cpu)); old_base = per_cpu_ptr(&tvec_bases, cpu); - new_base = this_cpu_ptr(&tvec_bases); + new_base = get_cpu_ptr(&tvec_bases); /* * The caller is globally serialized and nobody else * takes two locks at once, deadlock is not possible. @@ -1590,6 +1590,7 @@ static void migrate_timers(int cpu) spin_unlock(&old_base->lock); spin_unlock_irq(&new_base->lock); + put_cpu_ptr(&tvec_bases); } static int timer_cpu_notify(struct notifier_block *self, |
