Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 1/4] jiffies: Remove HZ > USEC_PER_SEC special case | Date | Wed, 15 Jul 2015 00:37:50 +0200 |
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HZ never goes much further 1000 and a bit. And if we ever reach one tick per microsecond, we might be having a problem.
Lets stop maintaining this special case, just leave a paranoid check.
Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@kernel.org> Cc; John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> --- include/linux/jiffies.h | 9 +-------- kernel/time/time.c | 10 +++++++--- 2 files changed, 8 insertions(+), 11 deletions(-)
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h index 535fd3b..7c6febe 100644 --- a/include/linux/jiffies.h +++ b/include/linux/jiffies.h @@ -363,18 +363,11 @@ static 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/kernel/time/time.c b/kernel/time/time.c index 85d5bb1..ad1bf23 100644 --- 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; -- 2.1.4
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