[PATCH] CFS : Use NSEC_PER_MSEC and NSEC_PER_SEC in kernel/sched.c and kernel/sysctl.c

[PATCH] CFS : Use NSEC_PER_MSEC and NSEC_PER_SEC in kernel/sched.c and kernel/sysctl.c

[Eric Dumazet]

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1) hardcoded 1000000000 value is used five times in places where NSEC_PER_SEC 
might be more readable.

2) A conversion from nsec to msec uses the hardcoded 1000000 value, which is a 
candidate for NSEC_PER_MSEC.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>


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diff --git a/kernel/sched.c b/kernel/sched.c
index 3f6bd11..57c539d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -75,7 +75,7 @@
  */
 unsigned long long __attribute__((weak)) sched_clock(void)
 {
-	return (unsigned long long)jiffies * (1000000000 / HZ);
+	return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
 }
 
 /*
@@ -99,8 +99,8 @@ unsigned long long __attribute__((weak)) sched_clock(void)
 /*
  * Some helpers for converting nanosecond timing to jiffy resolution
  */
-#define NS_TO_JIFFIES(TIME)	((unsigned long)(TIME) / (1000000000 / HZ))
-#define JIFFIES_TO_NS(TIME)	((TIME) * (1000000000 / HZ))
+#define NS_TO_JIFFIES(TIME)	((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
+#define JIFFIES_TO_NS(TIME)	((TIME) * (NSEC_PER_SEC / HZ))
 
 #define NICE_0_LOAD		SCHED_LOAD_SCALE
 #define NICE_0_SHIFT		SCHED_LOAD_SHIFT
@@ -7228,7 +7228,7 @@ static u64 cpu_usage_read(struct cgroup *cgrp, struct cftype *cft)
 		spin_unlock_irqrestore(&cpu_rq(i)->lock, flags);
 	}
 	/* Convert from ns to ms */
-	do_div(res, 1000000);
+	do_div(res, NSEC_PER_MSEC);
 
 	return res;
 }
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 3b4efbe..6547f9a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -226,9 +226,9 @@ static struct ctl_table root_table[] = {
 
 #ifdef CONFIG_SCHED_DEBUG
 static unsigned long min_sched_granularity_ns = 100000;		/* 100 usecs */
-static unsigned long max_sched_granularity_ns = 1000000000;	/* 1 second */
+static unsigned long max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
 static unsigned long min_wakeup_granularity_ns;			/* 0 usecs */
-static unsigned long max_wakeup_granularity_ns = 1000000000;	/* 1 second */
+static unsigned long max_wakeup_granularity_ns = NSEC_PER_SEC;	/* 1 second */
 #endif
 
 static struct ctl_table kern_table[] = {

Re: [PATCH] CFS : Use NSEC_PER_MSEC and NSEC_PER_SEC in kernel/sched.c and kernel/sysctl.c

[Ingo Molnar]

* Eric Dumazet <dada1@cosmosbay.com> wrote:

> 1) hardcoded 1000000000 value is used five times in places where 
> NSEC_PER_SEC might be more readable.
>
> 2) A conversion from nsec to msec uses the hardcoded 1000000 value, which 
> is a candidate for NSEC_PER_MSEC.
>
> Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>

thanks, applied.

	Ingo