From: Eric Dumazet <eric.dumazet@gmail.com>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: torvalds@linux-foundation.org, tj@kernel.org,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, paul.gortmaker@windriver.com,
davem@davemloft.net, rostedt@goodmis.org, mingo@elte.hu,
ebiederm@xmission.com, aarcange@redhat.com, ericvh@gmail.com,
netdev@vger.kernel.org
Subject: Re: [RFC v2 1/7] hashtable: introduce a small and naive hashtable
Date: Fri, 03 Aug 2012 19:39:10 +0200 [thread overview]
Message-ID: <1344015550.9299.1387.camel@edumazet-glaptop> (raw)
In-Reply-To: <1344003788-1417-2-git-send-email-levinsasha928@gmail.com>
On Fri, 2012-08-03 at 16:23 +0200, Sasha Levin wrote:
> This hashtable implementation is using hlist buckets to provide a simple
> hashtable to prevent it from getting reimplemented all over the kernel.
>
> +static void hash_add(struct hash_table *ht, struct hlist_node *node, long key)
> +{
> + hlist_add_head(node,
> + &ht->buckets[hash_long((unsigned long)key, HASH_BITS(ht))]);
> +}
> +
Why key is a long, casted later to "unsigned long" ?
hash_long() is expensive on 64bit arches, and not really needed
if key is an u32 from the beginning ( I am referring to your patches 6 &
7 using jhash() )
Maybe you could use a macro, so that we can automatically select
hash_32() if key is an u32, and hash_long() for other types.
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next prev parent reply other threads:[~2012-08-03 17:39 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-03 14:23 [RFC v2 0/7] generic hashtable implementation Sasha Levin
2012-08-03 14:23 ` [RFC v2 1/7] hashtable: introduce a small and naive hashtable Sasha Levin
2012-08-03 17:15 ` Tejun Heo
2012-08-03 17:16 ` Tejun Heo
2012-08-03 21:19 ` Sasha Levin
2012-08-03 21:30 ` Tejun Heo
2012-08-03 21:36 ` Sasha Levin
2012-08-03 21:44 ` Tejun Heo
2012-08-03 21:41 ` Sasha Levin
2012-08-03 21:48 ` Tejun Heo
2012-08-03 22:20 ` Sasha Levin
2012-08-03 22:23 ` Tejun Heo
2012-08-03 22:26 ` Sasha Levin
2012-08-03 22:29 ` Linus Torvalds
2012-08-03 22:36 ` Tejun Heo
2012-08-03 23:47 ` Linus Torvalds
2012-08-04 0:03 ` Sasha Levin
2012-08-04 0:05 ` Linus Torvalds
2012-08-04 0:33 ` Sasha Levin
2012-08-04 0:05 ` Tejun Heo
2012-08-03 17:39 ` Eric Dumazet [this message]
2012-08-03 14:23 ` [RFC v2 2/7] user_ns: use new hashtable implementation Sasha Levin
2012-08-05 0:58 ` Eric W. Biederman
2012-08-03 14:23 ` [RFC v2 3/7] mm,ksm: " Sasha Levin
2012-08-03 14:23 ` [RFC v2 4/7] workqueue: " Sasha Levin
2012-08-03 14:23 ` [RFC v2 5/7] mm/huge_memory: " Sasha Levin
2012-08-03 14:23 ` [RFC v2 6/7] tracepoint: " Sasha Levin
2012-08-05 0:36 ` Steven Rostedt
2012-08-05 16:31 ` Mathieu Desnoyers
2012-08-05 17:03 ` Sasha Levin
2012-08-05 17:12 ` Mathieu Desnoyers
2012-08-03 14:23 ` [RFC v2 7/7] net,9p: " Sasha Levin
2012-08-03 18:00 ` Eric Dumazet
2012-08-03 21:14 ` Sasha Levin
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