From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: Re: [PATCH v7 10/16] dlm: use new hashtable implementation Date: Mon, 29 Oct 2012 08:46:55 -0400 Message-ID: <20121029124655.GD11733@Krystal> References: <1351450948-15618-1-git-send-email-levinsasha928@gmail.com> <1351450948-15618-10-git-send-email-levinsasha928@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1351450948-15618-10-git-send-email-levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sasha Levin Cc: torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, paul.gortmaker-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org, rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org, mingo-X9Un+BFzKDI@public.gmane.org, ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org, aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, ericvh-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org, eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, agk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, neilb-l3A5Bk7waGM@public.gmane.org, ccaulfie-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, teigland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org, bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org, fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jesse-l0M0P4e3n4LQT0dZR+AlfA@public.gmane.org, venkat.x.venkatsubra-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, ejt-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, snitzer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, edumazet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dev-yBygre7rU0TnMu66kgdUjQ@public.gmane.org, rds-devel-N0ozoZBvEnrZJqsBc5GL+g@public.gmane.org, lw-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org List-Id: dm-devel.ids * Sasha Levin (levinsasha928-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org) wrote: [...] > @@ -158,34 +159,21 @@ static int dlm_allow_conn; > static struct workqueue_struct *recv_workqueue; > static struct workqueue_struct *send_workqueue; > > -static struct hlist_head connection_hash[CONN_HASH_SIZE]; > +static struct hlist_head connection_hash[CONN_HASH_BITS]; > static DEFINE_MUTEX(connections_lock); > static struct kmem_cache *con_cache; > > static void process_recv_sockets(struct work_struct *work); > static void process_send_sockets(struct work_struct *work); > > - > -/* This is deliberately very simple because most clusters have simple > - sequential nodeids, so we should be able to go straight to a connection > - struct in the array */ > -static inline int nodeid_hash(int nodeid) > -{ > - return nodeid & (CONN_HASH_SIZE-1); > -} There is one thing I dislike about this change: you remove a useful comment. It's good to be informed of the reason why a direct mapping "value -> hash" without any dispersion function is preferred here. Thanks, Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail.openrapids.net ([64.15.138.104]:58437 "EHLO blackscsi.openrapids.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751318Ab2J2Mq5 (ORCPT ); Mon, 29 Oct 2012 08:46:57 -0400 Date: Mon, 29 Oct 2012 08:46:55 -0400 From: Mathieu Desnoyers 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 Subject: Re: [PATCH v7 10/16] dlm: use new hashtable implementation Message-ID: <20121029124655.GD11733@Krystal> References: <1351450948-15618-1-git-send-email-levinsasha928@gmail.com> <1351450948-15618-10-git-send-email-levinsasha928@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1351450948-15618-10-git-send-email-levinsasha928@gmail.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: * Sasha Levin (levinsasha928@gmail.com) wrote: [...] > @@ -158,34 +159,21 @@ static int dlm_allow_conn; > static struct workqueue_struct *recv_workqueue; > static struct workqueue_struct *send_workqueue; > > -static struct hlist_head connection_hash[CONN_HASH_SIZE]; > +static struct hlist_head connection_hash[CONN_HASH_BITS]; > static DEFINE_MUTEX(connections_lock); > static struct kmem_cache *con_cache; > > static void process_recv_sockets(struct work_struct *work); > static void process_send_sockets(struct work_struct *work); > > - > -/* This is deliberately very simple because most clusters have simple > - sequential nodeids, so we should be able to go straight to a connection > - struct in the array */ > -static inline int nodeid_hash(int nodeid) > -{ > - return nodeid & (CONN_HASH_SIZE-1); > -} There is one thing I dislike about this change: you remove a useful comment. It's good to be informed of the reason why a direct mapping "value -> hash" without any dispersion function is preferred here. Thanks, Mathieu -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx106.postini.com [74.125.245.106]) by kanga.kvack.org (Postfix) with SMTP id 3DB756B0069 for ; Mon, 29 Oct 2012 08:46:57 -0400 (EDT) Date: Mon, 29 Oct 2012 08:46:55 -0400 From: Mathieu Desnoyers Subject: Re: [PATCH v7 10/16] dlm: use new hashtable implementation Message-ID: <20121029124655.GD11733@Krystal> References: <1351450948-15618-1-git-send-email-levinsasha928@gmail.com> <1351450948-15618-10-git-send-email-levinsasha928@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1351450948-15618-10-git-send-email-levinsasha928@gmail.com> 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 * Sasha Levin (levinsasha928@gmail.com) wrote: [...] > @@ -158,34 +159,21 @@ static int dlm_allow_conn; > static struct workqueue_struct *recv_workqueue; > static struct workqueue_struct *send_workqueue; > > -static struct hlist_head connection_hash[CONN_HASH_SIZE]; > +static struct hlist_head connection_hash[CONN_HASH_BITS]; > static DEFINE_MUTEX(connections_lock); > static struct kmem_cache *con_cache; > > static void process_recv_sockets(struct work_struct *work); > static void process_send_sockets(struct work_struct *work); > > - > -/* This is deliberately very simple because most clusters have simple > - sequential nodeids, so we should be able to go straight to a connection > - struct in the array */ > -static inline int nodeid_hash(int nodeid) > -{ > - return nodeid & (CONN_HASH_SIZE-1); > -} There is one thing I dislike about this change: you remove a useful comment. It's good to be informed of the reason why a direct mapping "value -> hash" without any dispersion function is preferred here. 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