From: Vincent Bernat <vincent@bernat.im>
To: Julian Anastasov <ja@ssi.bg>
Cc: Wensong Zhang <wensong@linux-vs.org>,
Simon Horman <horms@verge.net.au>,
"David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, lvs-devel@vger.kernel.org
Subject: Re: [PATCH net-next v1] ipvs: fix multiplicative hashing in sh/dh/lblc/lblcr algorithms
Date: Sun, 01 Apr 2018 12:16:10 +0200 [thread overview]
Message-ID: <m3lge7dyfp.fsf@luffy.cx> (raw)
In-Reply-To: <alpine.LFD.2.20.1804011037200.1933@ja.home.ssi.bg> (Julian Anastasov's message of "Sun, 1 Apr 2018 11:11:08 +0300 (EEST)")
❦ 1 avril 2018 11:11 +0300, Julian Anastasov <ja@ssi.bg> :
>> - return (ntohl(addr_fold)*2654435761UL) & IP_VS_DH_TAB_MASK;
>> + return ((ntohl(addr_fold)*2654435761U) >>
>> + (32 - IP_VS_DH_TAB_BITS)) &
>> + IP_VS_DH_TAB_MASK;
>
> Looks like the '& mask' part is not needed, still,
> it does not generate extra code. I see that other code uses
> hash_32(val, bits) from include/linux/hash.h but note that it
> used different ratio before Linux 4.7, in case someone backports
> this patch on old kernels. So, I don't have preference what should
> be used, may be return hash_32(ntohl(addr_fold), IP_VS_DH_TAB_BITS)
> is better.
I didn't notice this macro. I think this is a better option. Let me
amend the patch.
--
Don't stop with your first draft.
- The Elements of Programming Style (Kernighan & Plauger)
next prev parent reply other threads:[~2018-04-01 10:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-31 22:28 [PATCH net-next v1] ipvs: fix multiplicative hashing in sh/dh/lblc/lblcr algorithms Vincent Bernat
2018-04-01 8:11 ` Julian Anastasov
2018-04-01 10:16 ` Vincent Bernat [this message]
2018-04-01 10:27 ` [PATCH net-next v2] " Vincent Bernat
2018-04-01 11:11 ` Julian Anastasov
2018-04-09 7:16 ` Simon Horman
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