From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx167.postini.com [74.125.245.167]) by kanga.kvack.org (Postfix) with SMTP id DB6006B0069 for ; Sun, 19 Aug 2012 10:16:43 -0400 (EDT) Date: Sun, 19 Aug 2012 10:16:41 -0400 From: Mathieu Desnoyers Subject: Re: [PATCH v2 01/16] hashtable: introduce a small and naive hashtable Message-ID: <20120819141641.GA9082@Krystal> References: <1345337550-24304-1-git-send-email-levinsasha928@gmail.com> <1345337550-24304-2-git-send-email-levinsasha928@gmail.com> <20120819131637.GA8272@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120819131637.GA8272@Krystal> Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin 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, josh@joshtriplett.org, eric.dumazet@gmail.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 * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote: > * Sasha Levin (levinsasha928@gmail.com) wrote: [...] > > +/** > > + * hash_for_each_possible - iterate over all possible objects for a given key > > + * @name: hashtable to iterate > > + * @obj: the type * to use as a loop cursor for each bucket > > + * @bits: bit count of hashing function of the hashtable > > + * @node: the &struct list_head to use as a loop cursor for each bucket > > + * @member: the name of the hlist_node within the struct > > + * @key: the key of the objects to iterate over > > + */ > > +#define hash_for_each_possible_size(name, obj, bits, node, member, key) \ > > + hlist_for_each_entry(obj, node, &name[hash_min(key, bits)], member) > > Second point: "for_each_possible" does not express the iteration scope. > Citing WordNet: "possible adj 1: capable of happening or existing;" -- > which has nothing to do with iteration on duplicate keys within a hash > table. > > I would recommend to rename "possible" to "duplicate", e.g.: > > hash_for_each_duplicate() > > which clearly says what is the scope of this iteration: duplicate keys. OK, about this part: I now see that you iterate over all objects within the same hash chain. I guess the description "iterate over all possible objects for a given key" is misleading: it's not all objects with a given key, but rather all objects hashing to the same bucket. I understand that you don't want to build knowledge of the key comparison function in the iterator (which makes sense for a simple hash table). By the way, the comment "@obj: the type * to use as a loop cursor for each bucket" is also misleading: it's a loop cursor for each entry, since you iterate on all nodes within single bucket. Same for "@node: the &struct list_head to use as a loop cursor for each bucket". So with these documentation changes applied, hash_for_each_possible starts to make more sense, because it refers to entries that can _possibly_ be a match (or not). Other options would be hash_chain_for_each() or hash_bucket_for_each(). Thanks, Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org