[Devel] Re: [RFC PATCH v2] posix timers: allocate timer id per task

[Stanislav Kinsbursky]

17.10.2012 17:44, Eric Dumazet пишет:
> On Wed, 2012-10-17 at 17:18 +0400, Stanislav Kinsbursky wrote:
>
>> +static int hash(struct signal_struct *sig, unsigned int nr)
>> +{
>> +	int hash = hash_ptr(sig, POSIX_TIMERS_HASH_BITS);
>> +	return hash ^ hash_32(nr, POSIX_TIMERS_HASH_BITS);
>> +}
>> +
>
> This is quite expensive on 64 bit arches. I suggest instead :
>
> return hash_32(hash32_ptr(sig) ^ nr, POSIX_TIMERS_HASH_BITS);
>
>

I'm not familiar with hashing costs, so sure, I'll update.

-- 
Best regards,
Stanislav Kinsbursky