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| author | Venkatesh Pallipadi <venki@google.com> | 2010-12-21 17:09:01 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-01-26 12:33:20 +0100 |
| commit | a1dabb6bfffccb897eff3e1d102dacf2a4bedf3b (patch) | |
| tree | 412e36223e65fca0bd8ea7db6a57553a25799245 /kernel/time.c | |
| parent | 4dd53d891ca46dcc1fde0376a33540d3fd83cb9a (diff) | |
| download | lwn-a1dabb6bfffccb897eff3e1d102dacf2a4bedf3b.tar.gz lwn-a1dabb6bfffccb897eff3e1d102dacf2a4bedf3b.zip | |
time: Add nsecs_to_cputime64 interface for asm-generic
Add nsecs_to_cputime64 interface. This is used in following patches that
updates cpu irq stat based on ns granularity info in IRQ_TIME_ACCOUNTING.
Tested-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1292980144-28796-3-git-send-email-venki@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/time.c')
| -rw-r--r-- | kernel/time.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/kernel/time.c b/kernel/time.c index 32174359576f..55337a816b20 100644 --- a/kernel/time.c +++ b/kernel/time.c @@ -645,7 +645,7 @@ u64 nsec_to_clock_t(u64 x) } /** - * nsecs_to_jiffies - Convert nsecs in u64 to jiffies + * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64 * * @n: nsecs in u64 * @@ -657,7 +657,7 @@ u64 nsec_to_clock_t(u64 x) * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years */ -unsigned long nsecs_to_jiffies(u64 n) +u64 nsecs_to_jiffies64(u64 n) { #if (NSEC_PER_SEC % HZ) == 0 /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */ @@ -674,6 +674,25 @@ unsigned long nsecs_to_jiffies(u64 n) #endif } + +/** + * nsecs_to_jiffies - Convert nsecs in u64 to jiffies + * + * @n: nsecs in u64 + * + * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64. + * And this doesn't return MAX_JIFFY_OFFSET since this function is designed + * for scheduler, not for use in device drivers to calculate timeout value. + * + * note: + * NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512) + * ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years + */ +unsigned long nsecs_to_jiffies(u64 n) +{ + return (unsigned long)nsecs_to_jiffies64(n); +} + #if (BITS_PER_LONG < 64) u64 get_jiffies_64(void) { |