From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55D62C43387 for ; Wed, 19 Dec 2018 18:36:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E55B20672 for ; Wed, 19 Dec 2018 18:36:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728802AbeLSSgB (ORCPT ); Wed, 19 Dec 2018 13:36:01 -0500 Received: from fieldses.org ([173.255.197.46]:47068 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728458AbeLSSgB (ORCPT ); Wed, 19 Dec 2018 13:36:01 -0500 Received: by fieldses.org (Postfix, from userid 2815) id 6C3EC492; Wed, 19 Dec 2018 13:36:00 -0500 (EST) Date: Wed, 19 Dec 2018 13:36:00 -0500 From: "J. Bruce Fields" To: Scott Mayhew Cc: jlayton@kernel.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH v2 3/3] nfsd: keep a tally of RECLAIM_COMPLETE operations when using nfsdcld Message-ID: <20181219183600.GC28626@fieldses.org> References: <20181218142926.27933-1-smayhew@redhat.com> <20181218142926.27933-4-smayhew@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181218142926.27933-4-smayhew@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Tue, Dec 18, 2018 at 09:29:26AM -0500, Scott Mayhew wrote: > When using nfsdcld for NFSv4 client tracking, track the number of > RECLAIM_COMPLETE operations we receive from "known" clients to help in > deciding if we can lift the grace period early (or whether we need to > start a v4 grace period at all). > > Signed-off-by: Scott Mayhew > --- > fs/nfsd/netns.h | 3 +++ > fs/nfsd/nfs4recover.c | 5 +++++ > fs/nfsd/nfs4state.c | 52 +++++++++++++++++++++++++++++++++++++++++++ > fs/nfsd/nfsctl.c | 1 + > 4 files changed, 61 insertions(+) > > diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h > index 32cb8c027483..b42aaa22fba2 100644 > --- a/fs/nfsd/netns.h > +++ b/fs/nfsd/netns.h > @@ -104,6 +104,9 @@ struct nfsd_net { > time_t nfsd4_grace; > bool somebody_reclaimed; > > + bool track_reclaim_completes; > + atomic_t nr_reclaim_complete; > + > bool nfsd_net_up; > bool lockd_up; > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c > index 89c2a27956d0..ae74814b2397 100644 > --- a/fs/nfsd/nfs4recover.c > +++ b/fs/nfsd/nfs4recover.c > @@ -1251,6 +1251,7 @@ nfsd4_cld_grace_done(struct nfsd_net *nn) > free_cld_upcall(cup); > out_err: > nfs4_release_reclaim(nn); > + atomic_set(&nn->nr_reclaim_complete, 0); > if (ret) > printk(KERN_ERR "NFSD: Unable to end grace period: %d\n", ret); > } > @@ -1270,6 +1271,8 @@ nfs4_cld_state_init(struct net *net) > for (i = 0; i < CLIENT_HASH_SIZE; i++) > INIT_LIST_HEAD(&nn->reclaim_str_hashtbl[i]); > nn->reclaim_str_hashtbl_size = 0; > + nn->track_reclaim_completes = true; > + atomic_set(&nn->nr_reclaim_complete, 0); > > return 0; > } > @@ -1279,6 +1282,7 @@ nfs4_cld_state_shutdown(struct net *net) > { > struct nfsd_net *nn = net_generic(net, nfsd_net_id); > > + nn->track_reclaim_completes = false; > kfree(nn->reclaim_str_hashtbl); > } > > @@ -1318,6 +1322,7 @@ nfsd4_cld_tracking_exit(struct net *net) > struct nfsd_net *nn = net_generic(net, nfsd_net_id); > > nfs4_release_reclaim(nn); > + atomic_set(&nn->nr_reclaim_complete, 0); > nfsd4_remove_cld_pipe(net); > nfs4_cld_state_shutdown(net); > } > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 777fbb0d2761..5dfc3cd51d08 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -77,6 +77,7 @@ static u64 current_sessionid = 1; > /* forward declarations */ > static bool check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner); > static void nfs4_free_ol_stateid(struct nfs4_stid *stid); > +void nfsd4_end_grace(struct nfsd_net *nn); > > /* Locking: */ > > @@ -1988,10 +1989,41 @@ destroy_client(struct nfs4_client *clp) > __destroy_client(clp); > } > > +static void inc_reclaim_complete(struct nfs4_client *clp) > +{ > + struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); > + > + if (!nn->track_reclaim_completes) > + return; > + if (!test_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &clp->cl_flags)) > + return; Looking at the code.... This test will never fail, will it? We could make it a WARN_ON_ONCE(!test_bit(...)) but it doesn't look like a likely bug to me. > + if (!nfsd4_find_reclaim_client(clp->cl_name, nn)) > + return; > + if (atomic_inc_return(&nn->nr_reclaim_complete) == > + nn->reclaim_str_hashtbl_size) { > + printk(KERN_INFO "NFSD: all clients done reclaiming, ending NFSv4 grace period (net %x)\n", > + clp->net->ns.inum); > + nfsd4_end_grace(nn); > + } > +} > + > +static void dec_reclaim_complete(struct nfs4_client *clp) > +{ > + struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id); > + > + if (!nn->track_reclaim_completes) > + return; > + if (!test_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &clp->cl_flags)) > + return; > + if (nfsd4_find_reclaim_client(clp->cl_name, nn)) > + atomic_dec(&nn->nr_reclaim_complete); > +} > + > static void expire_client(struct nfs4_client *clp) > { > unhash_client(clp); > nfsd4_client_record_remove(clp); > + dec_reclaim_complete(clp); > __destroy_client(clp); > } This doesn't look right to me. If a client reclaims and then immediately calls DESTROY_CLIENTID or something--that should still count as a reclaim, and that shouldn't prevent us from ending the grace period early. I think dec_reclaim_complete is unnecessary. --b. > > @@ -3339,6 +3371,7 @@ nfsd4_reclaim_complete(struct svc_rqst *rqstp, > > status = nfs_ok; > nfsd4_client_record_create(cstate->session->se_client); > + inc_reclaim_complete(cstate->session->se_client); > out: > return status; > } > @@ -4734,6 +4767,10 @@ static bool clients_still_reclaiming(struct nfsd_net *nn) > unsigned long double_grace_period_end = nn->boot_time + > 2 * nn->nfsd4_lease; > > + if (nn->track_reclaim_completes && > + atomic_read(&nn->nr_reclaim_complete) == > + nn->reclaim_str_hashtbl_size) > + return false; > if (!nn->somebody_reclaimed) > return false; > nn->somebody_reclaimed = false; > @@ -7253,10 +7290,25 @@ nfs4_state_start_net(struct net *net) > return ret; > locks_start_grace(net, &nn->nfsd4_manager); > nfsd4_client_tracking_init(net); > + if (nn->track_reclaim_completes && nn->reclaim_str_hashtbl_size == 0) > + goto skip_grace; > printk(KERN_INFO "NFSD: starting %ld-second grace period (net %x)\n", > nn->nfsd4_grace, net->ns.inum); > queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_grace * HZ); > return 0; > + > +skip_grace: > + printk(KERN_INFO "NFSD: no clients to reclaim, skipping NFSv4 grace period (net %x)\n", > + net->ns.inum); > + queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_lease * HZ); > + /* > + * we could call nfsd4_end_grace() here, but it has a dprintk() > + * that would be confusing if debug logging is enabled > + */ > + nn->grace_ended = true; > + nfsd4_record_grace_done(nn); > + locks_end_grace(&nn->nfsd4_manager); > + return 0; > } > > /* initialization to perform when the nfsd service is started: */ > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c > index 6384c9b94898..950ac6683be9 100644 > --- a/fs/nfsd/nfsctl.c > +++ b/fs/nfsd/nfsctl.c > @@ -1240,6 +1240,7 @@ static __net_init int nfsd_init_net(struct net *net) > nn->nfsd4_lease = 45; /* default lease time */ > nn->nfsd4_grace = 45; > nn->somebody_reclaimed = false; > + nn->track_reclaim_completes = false; > nn->clverifier_counter = prandom_u32(); > nn->clientid_counter = prandom_u32(); > nn->s2s_cp_cl_id = nn->clientid_counter++; > -- > 2.17.1