From: Sasha Levin <levinsasha928@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: torvalds@linux-foundation.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,
josh@joshtriplett.org, eric.dumazet@gmail.com,
mathieu.desnoyers@efficios.com, axboe@kernel.dk, agk@redhat.com,
dm-devel@redhat.com, neilb@suse.de, ccaulfie@redhat.com,
teigland@redhat.com, Trond.Myklebust@netapp.com,
bfields@fieldses.org, fweisbec@gmail.com, jesse@nicira.com,
venkat.x.venkatsubra@oracle.com, ejt@redhat.com,
snitzer@redhat.com, edumazet@google.com,
linux-nfs@vger.kernel.org, dev@openvswitch.org,
rds-devel@oss.oracle.com, lw@cn.fujitsu.com
Subject: Re: [PATCH v3 01/17] hashtable: introduce a small and naive hashtable
Date: Fri, 24 Aug 2012 22:53:45 +0200 [thread overview]
Message-ID: <5037E9D9.9000605@gmail.com> (raw)
In-Reply-To: <20120824203332.GF21325@google.com>
On 08/24/2012 10:33 PM, Tejun Heo wrote:
> Hello, Sasha.
>
> On Fri, Aug 24, 2012 at 10:11:55PM +0200, Sasha Levin wrote:
>>> If this implementation is about the common trivial case, why not just
>>> have the usual DECLARE/DEFINE_HASHTABLE() combination?
>>
>> When we add the dynamic non-resizable support, how would DEFINE_HASHTABLE() look?
>
> Hmmm? DECLARE/DEFINE are usually for static ones.
Yup, but we could be using the same API for dynamic non-resizable and static if
we go with the DECLARE/hash_init. We could switch between them (and other
implementations) without having to change the code.
>>> I don't know. If we stick to the static (or even !resize dymaic)
>>> straight-forward hash - and we need something like that - I don't see
>>> what the full encapsulation buys us other than a lot of trivial
>>> wrappers.
>>
>> Which macros do you consider as trivial within the current API?
>>
>> Basically this entire thing could be reduced to DEFINE/DECLARE_HASHTABLE and
>> get_bucket(), but it would make the life of anyone who wants a slightly
>> different hashtable a hell.
>
> Wouldn't the following be enough to get most of the benefits?
>
> * DECLARE/DEFINE
> * hash_head()
> * hash_for_each_head()
> * hash_add*()
> * hash_for_each_possible*()
* hash_for_each*() ?
Why do we need hash_head/hash_for_each_head()? I haven't stumbled on a place yet
that needed direct access to the bucket itself.
Consider the following list:
- DECLARE
- hash_init
- hash_add
- hash_del
- hash_hashed
- hash_for_each_[rcu, safe]
- hash_for_each_possible[rcu, safe]
This basically means 11 macros/functions that would let us have full
encapsulation and will make it very easy for future implementations to work with
this API instead of making up a new one. It's also not significantly (+~2-3)
more than the ones you listed.
>> I think that right now the only real trivial wrapper is hash_hashed(), and I
>> think it's a price worth paying to have a single hashtable API instead of
>> fragmenting it when more implementations come along.
>
> I'm not objecting strongly against full encapsulation but having this
> many thin wrappers makes me scratch my head.
>
> Thanks.
>
next prev parent reply other threads:[~2012-08-24 20:53 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 2:26 [PATCH v3 00/17] generic hashtable implementation Sasha Levin
2012-08-22 2:26 ` [PATCH v3 01/17] hashtable: introduce a small and naive hashtable Sasha Levin
2012-08-22 18:01 ` Tejun Heo
2012-08-22 23:54 ` Ryan Mallon
2012-08-23 0:24 ` Sasha Levin
2012-08-23 20:04 ` Tejun Heo
2012-08-24 19:47 ` Sasha Levin
2012-08-24 19:59 ` Tejun Heo
2012-08-24 20:11 ` Sasha Levin
2012-08-24 20:33 ` Tejun Heo
2012-08-24 20:53 ` Sasha Levin [this message]
2012-08-24 21:23 ` Tejun Heo
2012-08-24 22:59 ` Sasha Levin
2012-08-24 23:07 ` Tejun Heo
2012-08-25 4:24 ` Mathieu Desnoyers
2012-08-28 9:56 ` Sasha Levin
2012-08-28 10:11 ` Mathieu Desnoyers
2012-08-28 11:27 ` Sasha Levin
2012-08-28 11:56 ` Mathieu Desnoyers
2012-08-28 23:00 ` Mathieu Desnoyers
2012-09-04 15:35 ` Steven Rostedt
2012-09-04 16:30 ` Pedro Alves
2012-09-04 16:40 ` Pedro Alves
2012-09-04 17:01 ` Mathieu Desnoyers
2012-09-06 13:53 ` Sasha Levin
2012-09-06 14:19 ` Pedro Alves
2012-09-06 14:33 ` Mathieu Desnoyers
2012-09-06 14:36 ` David Laight
2012-09-06 14:55 ` Josh Triplett
2012-09-06 15:11 ` Steven Rostedt
2012-09-06 15:49 ` Sasha Levin
2012-09-06 16:00 ` Steven Rostedt
2012-09-06 16:21 ` Sasha Levin
2012-09-06 16:50 ` Mathieu Desnoyers
2012-09-06 17:01 ` Sasha Levin
2012-09-06 17:02 ` Mathieu Desnoyers
2012-09-06 17:15 ` Steven Rostedt
2012-09-04 17:17 ` Steven Rostedt
2012-09-04 17:21 ` Pedro Alves
2012-09-04 20:59 ` Steven Rostedt
2012-09-04 21:51 ` Pedro Alves
2012-09-04 22:41 ` Steven Rostedt
2012-09-04 22:58 ` Pedro Alves
2012-09-04 23:27 ` Steven Rostedt
2012-09-04 16:32 ` Mathieu Desnoyers
2012-08-22 2:26 ` [PATCH v3 02/17] userns: use new hashtable implementation Sasha Levin
2012-08-22 2:26 ` [PATCH v3 03/17] mm,ksm: " Sasha Levin
2012-08-22 2:26 ` [PATCH v3 04/17] workqueue: " Sasha Levin
2012-08-22 18:05 ` Tejun Heo
2012-08-22 2:27 ` [PATCH v3 05/17] mm/huge_memory: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 06/17] tracepoint: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 07/17] net,9p: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 08/17] block,elevator: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 09/17] SUNRPC/cache: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 10/17] dlm: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 11/17] net,l2tp: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 12/17] dm: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 13/17] lockd: " Sasha Levin
2012-08-22 11:47 ` J. Bruce Fields
2012-08-22 12:13 ` Sasha Levin
2012-08-22 13:12 ` J. Bruce Fields
2012-08-22 13:22 ` Mathieu Desnoyers
2012-08-22 17:32 ` Sasha Levin
2012-08-22 2:27 ` [PATCH v3 14/17] net,rds: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 15/17] openvswitch: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 16/17] tracing output: " Sasha Levin
2012-08-22 2:27 ` [PATCH v3 17/17] SUNRPC: use new hashtable implementation in auth Sasha Levin
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