From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: NeilBrown <neilb@suse.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>,
James Simmons <jsimmons@infradead.org>,
Andreas Dilger <andreas.dilger@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Lustre Development List <lustre-devel@lists.lustre.org>
Subject: Re: [PATCH 00/20] staging: lustre: convert to rhashtable
Date: Mon, 23 Apr 2018 15:08:37 +0200 [thread overview]
Message-ID: <20180423130837.GA25183@kroah.com> (raw)
In-Reply-To: <152348312863.12394.11915752362061083241.stgit@noble>
On Thu, Apr 12, 2018 at 07:54:48AM +1000, NeilBrown wrote:
> libcfs in lustre has a resizeable hashtable.
> Linux already has a resizeable hashtable, rhashtable, which is better
> is most metrics. See https://lwn.net/Articles/751374/ in a few days
> for an introduction to rhashtable.
>
> This series converts lustre to use rhashtable. This affects several
> different tables, and each is different is various ways.
>
> There are two outstanding issues. One is that a bug in rhashtable
> means that we cannot enable auto-shrinking in one of the tables. That
> is documented as appropriate and should be fixed soon.
>
> The other is that rhashtable has an atomic_t which counts the elements
> in a hash table. At least one table in lustre went to some trouble to
> avoid any table-wide atomics, so that could lead to a regression.
> I'm hoping that rhashtable can be enhanced with the option of a
> per-cpu counter, or similar.
>
>
> I have enabled automatic shrinking on all tables where it makes sense
> and doesn't trigger the bug. I have also removed all hints concerning
> min/max size - I cannot see how these could be useful.
>
> The dump_pgcache debugfs file provided some interesting challenges. I
> think I have cleaned it up enough so that it all makes sense. An
> extra pair of eyes examining that code in particular would be
> appreciated.
>
> This series passes all the same tests that pass before the patches are
> applied.
I've taken the first 4 patches of this series, as they were "obviously
correct". I'll let you and James argue about the rest. Feel free to
resend when there's some sort of agreement.
thanks,
greg k-h
prev parent reply other threads:[~2018-04-23 13:08 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-11 21:54 [PATCH 00/20] staging: lustre: convert to rhashtable NeilBrown
2018-04-11 21:54 ` [PATCH 03/20] staging: lustre: convert obd uuid hash " NeilBrown
2018-04-11 21:54 ` [PATCH 04/20] staging: lustre: convert osc_quota " NeilBrown
2018-04-11 21:54 ` [PATCH 05/20] staging: lustre: separate buckets from ldlm hash table NeilBrown
2018-04-11 21:54 ` [PATCH 09/20] staging: lustre: convert ldlm_resource hash to rhashtable NeilBrown
2018-04-11 21:54 ` [PATCH 07/20] staging: lustre: ldlm: store name directly in namespace NeilBrown
2018-04-11 21:54 ` [PATCH 10/20] staging: lustre: make struct lu_site_bkt_data private NeilBrown
2018-04-11 21:54 ` [PATCH 02/20] staging: lustre: convert lov_pool to use rhashtable NeilBrown
2018-04-11 21:54 ` [PATCH 12/20] staging: lustre: lu_object: factor out extra per-bucket data NeilBrown
2018-04-11 21:54 ` [PATCH 08/20] staging: lustre: simplify ldlm_ns_hash_defs[] NeilBrown
2018-04-11 21:54 ` [PATCH 01/20] staging: lustre: ptlrpc: convert conn_hash to rhashtable NeilBrown
2018-04-11 21:54 ` [PATCH 06/20] staging: lustre: ldlm: add a counter to the per-namespace data NeilBrown
2018-04-11 21:54 ` [PATCH 11/20] staging: lustre: lu_object: discard extra lru count NeilBrown
2018-04-11 21:54 ` [PATCH 17/20] staging: lustre: use call_rcu() to free lu_object_headers NeilBrown
2018-04-11 21:54 ` [PATCH 15/20] staging: lustre: llite: use more private data in dump_pgcache NeilBrown
2018-04-11 21:54 ` [PATCH 16/20] staging: lustre: llite: remove redundant lookup " NeilBrown
2018-04-11 21:54 ` [PATCH 14/20] staging: lustre: fold lu_object_new() into lu_object_find_at() NeilBrown
2018-04-11 21:54 ` [PATCH 13/20] staging: lustre: lu_object: move retry logic inside htable_lookup NeilBrown
2018-04-11 21:54 ` [PATCH 18/20] staging: lustre: change how "dump_page_cache" walks a hash table NeilBrown
2018-04-11 21:54 ` [PATCH 20/20] staging: lustre: remove cfs_hash resizeable hashtable implementation NeilBrown
2018-04-11 21:54 ` [PATCH 19/20] staging: lustre: convert lu_object cache to rhashtable NeilBrown
2018-04-17 3:35 ` [PATCH 00/20] staging: lustre: convert " James Simmons
2018-04-18 3:17 ` NeilBrown
2018-04-18 21:56 ` [lustre-devel] " Simmons, James A.
2018-04-23 13:08 ` Greg Kroah-Hartman [this message]
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