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Message-ID: <87621lo4ly.fsf@linaro.org>
Date: Thu, 21 Feb 2013 11:21:13 -0800
From: Kevin Hilman <khilman@...aro.org>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Mats Liljegren <mats.liljegren@...a.com>,
linaro-dev@...ts.linaro.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC/PATCH 4/5] cputime: use do_div() for nsec resolution conversion helpers
Namhyung Kim <namhyung@...nel.org> writes:
> Hi Kevin,
>
> On Wed, Feb 20, 2013 at 11:41:41AM -0800, Kevin Hilman wrote:
>> For the nsec resolution conversions to be useful on non 64-bit
>> architectures, do_div() needs to be used for the 64-bit divisions.
>>
>> Signed-off-by: Kevin Hilman <khilman@...aro.org>
>> ---
>> include/asm-generic/cputime_nsecs.h | 51 +++++++++++++++++++++++++++----------
>> 1 file changed, 37 insertions(+), 14 deletions(-)
>>
>> diff --git a/include/asm-generic/cputime_nsecs.h b/include/asm-generic/cputime_nsecs.h
>> index b6485ca..daa6075 100644
>> --- a/include/asm-generic/cputime_nsecs.h
>> +++ b/include/asm-generic/cputime_nsecs.h
>> @@ -24,13 +24,17 @@ typedef u64 __nocast cputime64_t;
>> /*
>> * Convert cputime <-> jiffies (HZ)
>> */
>> -#define cputime_to_jiffies(__ct) \
>> - ((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
>> +static inline u64 cputime_to_jiffies(const cputime_t ct)
>> +{
>> + cputime_t __ct = ct;
>
> Why it removed the "(__force u64)" conversion part? Shouldn't it be:
>
> u64 __ct = (__force u64) ct;
>
> ?
You're right, that was an oversight. Updated patch below.
Frederic, if you merge this, please take the one below with the __force
attributes added back.
I've updated my branch to include the fixed version.
Kevin
>From a8a0a8b8b12512a7f862ade459cd88d2b48e2bf3 Mon Sep 17 00:00:00 2001
From: Kevin Hilman <khilman@...aro.org>
Date: Thu, 14 Feb 2013 11:27:36 -0800
Subject: [PATCH 4/5] cputime: use do_div() for nsec resolution conversion
helpers
For the nsec resolution conversions to be useful on non 64-bit
architectures, do_div() needs to be used for the 64-bit divisions.
Special thanks to Namhyung Kim for pointing out omissions of the
__force attribute in an earlier version.
Cc: Namhyung Kim <namhyung@...nel.org>
Signed-off-by: Kevin Hilman <khilman@...aro.org>
---
include/asm-generic/cputime_nsecs.h | 51 +++++++++++++++++++++++++++----------
1 file changed, 37 insertions(+), 14 deletions(-)
diff --git a/include/asm-generic/cputime_nsecs.h b/include/asm-generic/cputime_nsecs.h
index b6485ca..d4944c9 100644
--- a/include/asm-generic/cputime_nsecs.h
+++ b/include/asm-generic/cputime_nsecs.h
@@ -24,13 +24,17 @@ typedef u64 __nocast cputime64_t;
/*
* Convert cputime <-> jiffies (HZ)
*/
-#define cputime_to_jiffies(__ct) \
- ((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
+static inline u64 cputime_to_jiffies(const cputime_t ct)
+{
+ u64 __ct = (__force u64) ct;
+
+ do_div(__ct, NSEC_PER_SEC / HZ);
+ return __ct;
+}
#define cputime_to_scaled(__ct) (__ct)
#define jiffies_to_cputime(__jif) \
(__force cputime_t)((__jif) * (NSEC_PER_SEC / HZ))
-#define cputime64_to_jiffies64(__ct) \
- ((__force u64)(__ct) / (NSEC_PER_SEC / HZ))
+#define cputime64_to_jiffies64(__ct) cputime_to_jiffies(__ct)
#define jiffies64_to_cputime64(__jif) \
(__force cputime64_t)((__jif) * (NSEC_PER_SEC / HZ))
@@ -44,8 +48,13 @@ typedef u64 __nocast cputime64_t;
/*
* Convert cputime <-> microseconds
*/
-#define cputime_to_usecs(__ct) \
- ((__force u64)(__ct) / NSEC_PER_USEC)
+static inline u64 cputime_to_usecs(const cputime_t ct)
+{
+ u64 __ct = (__force u64) ct;
+
+ do_div(__ct, NSEC_PER_USEC);
+ return __ct;
+}
#define usecs_to_cputime(__usecs) \
(__force cputime_t)((__usecs) * NSEC_PER_USEC)
#define usecs_to_cputime64(__usecs) \
@@ -54,8 +63,13 @@ typedef u64 __nocast cputime64_t;
/*
* Convert cputime <-> seconds
*/
-#define cputime_to_secs(__ct) \
- ((__force u64)(__ct) / NSEC_PER_SEC)
+static inline u64 cputime_to_secs(const cputime_t ct)
+{
+ u64 __ct = (__force u64) ct;
+
+ do_div(__ct, NSEC_PER_SEC);
+ return __ct;
+}
#define secs_to_cputime(__secs) \
(__force cputime_t)((__secs) * NSEC_PER_SEC)
@@ -69,8 +83,10 @@ static inline cputime_t timespec_to_cputime(const struct timespec *val)
}
static inline void cputime_to_timespec(const cputime_t ct, struct timespec *val)
{
- val->tv_sec = (__force u64) ct / NSEC_PER_SEC;
- val->tv_nsec = (__force u64) ct % NSEC_PER_SEC;
+ u64 __ct = (__force u64) ct;
+
+ val->tv_nsec = do_div(__ct, NSEC_PER_SEC);
+ val->tv_sec = __ct;
}
/*
@@ -83,15 +99,22 @@ static inline cputime_t timeval_to_cputime(struct timeval *val)
}
static inline void cputime_to_timeval(const cputime_t ct, struct timeval *val)
{
- val->tv_sec = (__force u64) ct / NSEC_PER_SEC;
- val->tv_usec = ((__force u64) ct % NSEC_PER_SEC) / NSEC_PER_USEC;
+ u64 __ct = (__force u64) ct;
+
+ val->tv_usec = do_div(__ct, NSEC_PER_SEC) / NSEC_PER_USEC;
+ val->tv_sec = __ct;
}
/*
* Convert cputime <-> clock (USER_HZ)
*/
-#define cputime_to_clock_t(__ct) \
- ((__force u64)(__ct) / (NSEC_PER_SEC / USER_HZ))
+static inline u64 cputime_to_clock_t(const cputime_t ct)
+{
+ u64 __ct = (__force u64) ct;
+
+ do_div(__ct, (NSEC_PER_SEC / USER_HZ));
+ return __ct;
+}
#define clock_t_to_cputime(__x) \
(__force cputime_t)((__x) * (NSEC_PER_SEC / USER_HZ))
--
1.8.1.2
--
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