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From: Olaf Kirch <okir@suse.de>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: NeilBrown <neilb@suse.de>, Andrew Morton <akpm@osdl.org>,
	nfs@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [NFS] [PATCH 004 of 19] knfsd: lockd: introduce nsm_handle
Date: Mon, 4 Sep 2006 10:48:46 +0200	[thread overview]
Message-ID: <20060904084846.GB28400@suse.de> (raw)
In-Reply-To: <1157128893.5632.74.camel@localhost>

On Fri, Sep 01, 2006 at 12:41:33PM -0400, Trond Myklebust wrote:
> The local statd process is supposed to decode the notification from the
> remote client/server, and then notify the kernel. It already sends that
> notification on a per-nlm_host basis (i.e. it the call down to the
> kernel contains the <address,version,transport protocol>.

Why does statd need to send the full <address,version,transport protocol>
to the kernel in the first place?

All that's really needed is a unique identification of the host having
rebooted, nevermind how we have been talking to it, and in what role.

I consider the current practice a side effect of a bad implementation
which duplicates a lot of state by dumping everything into the nlm_host.

With the current code, we cannot even monitor IPv6 addresses, because
there's not enough room in the NSM_MON packet. With my proposed change,
we can ditch version and transport protocol, and all of a sudden we
have 16 bytes for the address - ie enough to make IPv6 happy.

In the long run, we could clean out nlm_host even more - there's
a lot of cruft in there.

	h_name		just h_nsmhandle->sm_name
	h_gracewait	could be shared as well
	h_state		should move to nsmhandle as well
	h_nsmstate	currently not used, could move to nsmhandle as well
	h_pidcount	currently allocated per nlm_host, which leads
			to aliasing if we mix NFSv2 and v3 mounts

On a side note, we may want to always allocate an RPC client for each
nlm_host.  Then we can ditch the following variables as well, which are
in the rpc_client's portmap info anyway:

	h_proto		pm_prot
	h_version	pm_vers
	h_sema		useless
	h_nextrebind	we can stop rebinding every 60s, the sunrpc
			doesn't need that anymore. During recovery,
			we can just call rpc_force_rebind
			directly.

Or going even further, one could make the nlm_host agnostic of transports
and protocol versions. Just stick a (short) array of RPC clients in the
nlm_host - any code that places NLM calls will need some extra logic
to select the right client, but it would save on memory and reduce
complexity.

Olaf
-- 
Olaf Kirch   |  --- o --- Nous sommes du soleil we love when we play
okir@suse.de |    / | \   sol.dhoop.naytheet.ah kin.ir.samse.qurax

-- 
VGER BF report: H 2.68873e-09

  reply	other threads:[~2006-09-04  8:48 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-01  4:38 [PATCH 000 of 19] knfsd: lockd improvements NeilBrown
2006-09-01  4:38 ` [PATCH 001 of 19] knfsd: Hide use of lockd's h_monitored flag NeilBrown
2006-09-01  4:38 ` [PATCH 002 of 19] knfsd: Consolidate common code for statd->lockd notification NeilBrown
2006-09-01  4:38 ` [PATCH 003 of 19] knfsd: When looking up a lockd host, pass hostname & length NeilBrown
2006-09-01  4:38 ` [PATCH 004 of 19] knfsd: lockd: introduce nsm_handle NeilBrown
2006-09-01  6:17   ` Andrew Morton
2006-09-01 23:48     ` Neil Brown
2006-09-01  6:20   ` Andrew Morton
2006-09-01 23:50     ` Neil Brown
2006-09-01 15:50   ` [NFS] " Trond Myklebust
2006-09-01 16:11     ` Olaf Kirch
2006-09-01 16:41       ` Trond Myklebust
2006-09-04  8:48         ` Olaf Kirch [this message]
2006-09-01  4:38 ` [PATCH 005 of 19] knfsd: Misc minor fixes, indentation changes NeilBrown
2006-09-01  4:38 ` [PATCH 006 of 19] knfsd: lockd: Make nlm_host_rebooted use the nsm_handle NeilBrown
2006-09-01  4:38 ` [PATCH 007 of 19] knfsd: lockd: make the nsm upcalls " NeilBrown
2006-09-01  4:38 ` [PATCH 008 of 19] knfsd: lockd: make the hash chains use a hlist_node NeilBrown
2006-09-01  4:38 ` [PATCH 009 of 19] knfsd: lockd: Change list of blocked list to list_node NeilBrown
2006-09-01  4:39 ` [PATCH 010 of 19] knfsd: Change nlm_file to use a hlist NeilBrown
2006-09-01  4:39 ` [PATCH 011 of 19] knfsd: lockd: make nlm_traverse_* more flexible NeilBrown
2006-09-01  4:39 ` [PATCH 012 of 19] knfsd: lockd: Add nlm_destroy_host NeilBrown
2006-09-01  4:39 ` [PATCH 013 of 19] knfsd: Simplify nlmsvc_invalidate_all NeilBrown
2006-09-01  4:39 ` [PATCH 014 of 19] knfsd: lockd: optionally use hostnames for identifying peers NeilBrown
2006-09-01  4:39 ` [PATCH 015 of 19] knfsd: make nlmclnt_next_cookie SMP safe NeilBrown
2006-09-01  4:39 ` [PATCH 016 of 19] knfsd: match GRANTED_RES replies using cookies NeilBrown
2006-09-01 16:03   ` [NFS] " Trond Myklebust
2006-09-04  9:09     ` Olaf Kirch
2006-09-05 16:12       ` Trond Myklebust
2006-09-05 17:39         ` Olaf Kirch
2006-09-01  4:39 ` [PATCH 017 of 19] knfsd: Export nsm_local_state to user space via sysctl NeilBrown
2006-09-01  4:39 ` [PATCH 018 of 19] knfsd: lockd: fix use of h_nextrebind NeilBrown
2006-09-01 16:05   ` [NFS] " Trond Myklebust
2006-09-01  4:39 ` [PATCH 019 of 19] knfsd: Register all RPC programs with portmapper by default NeilBrown
2006-09-01 13:25   ` [NFS] " Peter Staubach
2006-09-01 13:29   ` Peter Staubach
2006-09-01 13:47     ` Olaf Kirch
2006-09-01 15:31   ` Chuck Lever
2006-09-01 15:54     ` Olaf Kirch
2006-09-01 16:08       ` Chuck Lever
2006-09-01 16:34         ` Peter Staubach
2006-09-01 16:13     ` Trond Myklebust

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