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SubjectRe: [PATCH v4 net-next 2/4] net: convert low latency sockets to sched_clock()
On 14/06/2013 06:12, Eric Dumazet wrote:
> On Fri, 2013-06-14 at 04:57 +0300, Eliezer Tamir wrote:
>> Use sched_clock() instead of get_cycles().
>> We can use sched_clock() because we don't care much about accuracy.
>> Remove the dependency on X86_TSC
>>
>> Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
>> ---
>
>>
>> -static inline bool can_poll_ll(cycles_t end_time)
>> +static inline bool can_poll_ll(u64 end_time)
>> {
>> - return !time_after((unsigned long)get_cycles(),
>> + return !time_after((unsigned long)sched_clock(),
>> (unsigned long)end_time);
>> }
>
> I do not really understand why you bother to have 64bit wide values,
> and then use these "unsigned long" casts here.
>
> On 32bit arches, this will really limit to 2^31 ns range.
>
> You should instead either :
> - use time_after_64() or
> - explicitly limit sysctl_net_ll_poll range

OK


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