From: Stanislav Kinsbursky <skinsbursky@parallels.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "peterz@infradead.org" <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devel@openvz.org" <devel@openvz.org>
Subject: Re: [RFC PATCH v2] posix timers: allocate timer id per task
Date: Wed, 17 Oct 2012 18:19:56 +0400 [thread overview]
Message-ID: <507EBE8C.2030707@parallels.com> (raw)
In-Reply-To: <1350481466.26103.464.camel@edumazet-glaptop>
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
next prev parent reply other threads:[~2012-10-17 14:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-17 13:18 [RFC PATCH v2] posix timers: allocate timer id per task Stanislav Kinsbursky
2012-10-17 13:44 ` Eric Dumazet
2012-10-17 14:19 ` Stanislav Kinsbursky [this message]
2012-10-17 13:57 ` Eric Dumazet
2012-10-17 14:26 ` Stanislav Kinsbursky
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