On Sat, Apr 25, 2009 at 12:13 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
> On Wed, Apr 01, 2009 at 07:28:01AM +1100, Greg Banks wrote:
>> Two new functions; svc_time_mark() remembers the current time
>> in a struct svc_time; svc_time_elapsed() calculates and returns
>> the time since a svc_time was marked.
>>
>> Signed-off-by: Greg Banks <gnb@xxxxxxx>
>> ---
>>
>> include/linux/sunrpc/svc.h | 12 ++++++++++++
>> net/sunrpc/svc.c | 25 +++++++++++++++++++++++++
>> 2 files changed, 37 insertions(+)
>>
>> Index: bfields/include/linux/sunrpc/svc.h
>> ===================================================================
>> --- bfields.orig/include/linux/sunrpc/svc.h
>> +++ bfields/include/linux/sunrpc/svc.h
>> @@ -18,6 +18,16 @@
>> #include <linux/sunrpc/svcauth.h>
>> #include <linux/wait.h>
>> #include <linux/mm.h>
>> +#include <linux/time.h>
>> +
>> +/*
>> + * Structure used to implement a fast lockless elapsed time measure.
>> + */
>> +struct svc_time
>> +{
>> + struct timespec st_spec;
>> +};
>
> Are struct svc_time, ...
>
>> +void
>> +svc_time_mark(struct svc_time *st)
>> +{
>> + getnstimeofday(&st->st_spec);
>> +}
>> +EXPORT_SYMBOL(svc_time_mark);
>
> ... and this function really necessary? If you're not too attached to
> them: it would seem simpler just to use struct timespec and
> getnstimeofday directly. (Well, at least simpler to read for someone
> familiar with the kernel but not with th nfs code.)
To be quite frank, no. They're historical; they were very necessary
in the original SLES10-based version of these patches because that
ancient kernel was missing some important time infrastructure bits.
In that code, the structure and functions did some very hairy and
arch-specific things involving jiffies and ITC/TSC registers. I was
being lazy by not eliding them during forward porting, and I'll do so
in the next version.
--
Greg.
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