From patchwork Tue Aug 30 21:48:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dai Ngo X-Patchwork-Id: 12959898 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF17CECAAA1 for ; Tue, 30 Aug 2022 21:48:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231207AbiH3Vs4 (ORCPT ); Tue, 30 Aug 2022 17:48:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231775AbiH3Vsq (ORCPT ); Tue, 30 Aug 2022 17:48:46 -0400 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CC768E981 for ; Tue, 30 Aug 2022 14:48:45 -0700 (PDT) Received: from pps.filterd (m0246630.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 27ULVKZl012650; Tue, 30 Aug 2022 21:48:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2022-7-12; bh=fp7T0BCC8WxexTa8mVnUd/fm3pwzMhERfnNLglyhy0Y=; b=xRwz3LSNai5fkvrcHquUBxQfVLCkMNuef85yL7/CXyjK9vfapR/9PGUKDyCJDCovp5RN PAd35ewpVlNbIFF2MwnQsiM60T5V0dFCApNG14s+9U99QGC0amNS9WyMl/hstFta/z4h BJXgy+kID7xi4d2KFxggp9nxQqrPjlzjJkOC3KMdBQKDvPaUhT9wbVq6X7j3WOaFnHDw /YXQHl7WGjYI7+QDDwcVEMdBpDPxUU4TPyIqWOz2CkI+TfeseSflBykRyIRnwco4pkX6 XK6rG0yu1QDEBVXnwn6Tna/QSMCZmYBxVS8KeMXsUmKyavEdrKdHJ9y2oY0GkIHz9Fba qg== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3j79pbyfxd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Aug 2022 21:48:40 +0000 Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 27ULcs5A008153; Tue, 30 Aug 2022 21:48:40 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3j79qapta7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Aug 2022 21:48:40 +0000 Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 27ULmcEN028504; Tue, 30 Aug 2022 21:48:39 GMT Received: from ca-common-hq.us.oracle.com (ca-common-hq.us.oracle.com [10.211.9.209]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 3j79qapt8q-3; Tue, 30 Aug 2022 21:48:39 +0000 From: Dai Ngo To: chuck.lever@oracle.com, jlayton@kernel.org Cc: linux-nfs@vger.kernel.org Subject: [PATCH v4 2/2] NFSD: add shrinker to reap courtesy clients on low memory condition Date: Tue, 30 Aug 2022 14:48:33 -0700 Message-Id: <1661896113-8013-3-git-send-email-dai.ngo@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1661896113-8013-1-git-send-email-dai.ngo@oracle.com> References: <1661896113-8013-1-git-send-email-dai.ngo@oracle.com> X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-30_12,2022-08-30_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 phishscore=0 mlxlogscore=999 adultscore=0 bulkscore=0 spamscore=0 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2208300097 X-Proofpoint-ORIG-GUID: BT17Rzbccgt3pYz3-LWQLPMownpUo3mK X-Proofpoint-GUID: BT17Rzbccgt3pYz3-LWQLPMownpUo3mK Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Add the courtesy client shrinker to react to low memory condition triggered by the memory shrinker. On the shrinker's count callback, we increment a callback counter and return the number of outstanding courtesy clients. When the laundromat runs, it checks if this counter is not zero and starts reaping old courtesy clients. The maximum number of clients to be reaped is limited to NFSD_CIENT_MAX_TRIM_PER_RUN (128). This limit is to prevent the laundromat from spending too much time reaping the clients and not processing other tasks in a timely manner. The laundromat is rescheduled to run sooner if it detects low low memory condition and there are more clients to reap. On the shrinker's scan callback, we return the number of clients That were reaped since the last scan callback. We can not reap the clients on the scan callback context since destroying the client might require call into the underlying filesystem or other subsystems which might allocate memory which can cause deadlock. Signed-off-by: Dai Ngo --- fs/nfsd/netns.h | 3 +++ fs/nfsd/nfs4state.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++---- fs/nfsd/nfsctl.c | 6 ++++-- fs/nfsd/nfsd.h | 9 +++++++-- 4 files changed, 62 insertions(+), 8 deletions(-) diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 2695dff1378a..2a604951623f 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -194,6 +194,9 @@ struct nfsd_net { int nfs4_max_clients; atomic_t nfsd_courtesy_client_count; + atomic_t nfsd_client_shrinker_cb_count; + atomic_t nfsd_client_shrinker_reapcount; + struct shrinker nfsd_client_shrinker; }; /* Simple check to find out if a given net was properly initialized */ diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index eaf7b4dcea33..9aed9eed1892 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4343,7 +4343,40 @@ nfsd4_init_slabs(void) return -ENOMEM; } -void nfsd4_init_leases_net(struct nfsd_net *nn) +static unsigned long +nfsd_courtesy_client_count(struct shrinker *shrink, struct shrink_control *sc) +{ + struct nfsd_net *nn = container_of(shrink, + struct nfsd_net, nfsd_client_shrinker); + + atomic_inc(&nn->nfsd_client_shrinker_cb_count); + mod_delayed_work(laundry_wq, &nn->laundromat_work, 0); + return (unsigned long)atomic_read(&nn->nfsd_courtesy_client_count); +} + +static unsigned long +nfsd_courtesy_client_scan(struct shrinker *shrink, struct shrink_control *sc) +{ + struct nfsd_net *nn = container_of(shrink, + struct nfsd_net, nfsd_client_shrinker); + unsigned long cnt; + + cnt = atomic_read(&nn->nfsd_client_shrinker_reapcount); + atomic_set(&nn->nfsd_client_shrinker_reapcount, 0); + return cnt; +} + +static int +nfsd_register_client_shrinker(struct nfsd_net *nn) +{ + nn->nfsd_client_shrinker.scan_objects = nfsd_courtesy_client_scan; + nn->nfsd_client_shrinker.count_objects = nfsd_courtesy_client_count; + nn->nfsd_client_shrinker.seeks = DEFAULT_SEEKS; + return register_shrinker(&nn->nfsd_client_shrinker, "nfsd-client"); +} + +int +nfsd4_init_leases_net(struct nfsd_net *nn) { struct sysinfo si; u64 max_clients; @@ -4364,6 +4397,8 @@ void nfsd4_init_leases_net(struct nfsd_net *nn) nn->nfs4_max_clients = max_t(int, max_clients, NFS4_CLIENTS_PER_GB); atomic_set(&nn->nfsd_courtesy_client_count, 0); + atomic_set(&nn->nfsd_client_shrinker_cb_count, 0); + return nfsd_register_client_shrinker(nn); } static void init_nfs4_replay(struct nfs4_replay *rp) @@ -5872,12 +5907,17 @@ static void nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist, struct laundry_time *lt) { - unsigned int maxreap, reapcnt = 0; + unsigned int maxreap = 0, reapcnt = 0; + int cb_cnt; struct list_head *pos, *next; struct nfs4_client *clp; - maxreap = (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients) ? - NFSD_CLIENT_MAX_TRIM_PER_RUN : 0; + cb_cnt = atomic_read(&nn->nfsd_client_shrinker_cb_count); + if (atomic_read(&nn->nfs4_client_count) >= nn->nfs4_max_clients || + cb_cnt) { + maxreap = NFSD_CLIENT_MAX_TRIM_PER_RUN; + atomic_set(&nn->nfsd_client_shrinker_cb_count, 0); + } INIT_LIST_HEAD(reaplist); spin_lock(&nn->client_lock); list_for_each_safe(pos, next, &nn->client_lru) { @@ -5903,6 +5943,8 @@ nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist, } } spin_unlock(&nn->client_lock); + if (cb_cnt) + atomic_add(reapcnt, &nn->nfsd_client_shrinker_reapcount); } static time64_t @@ -5943,6 +5985,8 @@ nfs4_laundromat(struct nfsd_net *nn) list_del_init(&clp->cl_lru); expire_client(clp); } + if (atomic_read(&nn->nfsd_client_shrinker_cb_count) > 0) + lt.new_timeo = NFSD_LAUNDROMAT_MINTIMEOUT; spin_lock(&state_lock); list_for_each_safe(pos, next, &nn->del_recall_lru) { dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 917fa1892fd2..597a26ad4183 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1481,11 +1481,12 @@ static __net_init int nfsd_init_net(struct net *net) goto out_idmap_error; nn->nfsd_versions = NULL; nn->nfsd4_minorversions = NULL; + retval = nfsd4_init_leases_net(nn); + if (retval) + goto out_drc_error; retval = nfsd_reply_cache_init(nn); if (retval) goto out_drc_error; - nfsd4_init_leases_net(nn); - get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key)); seqlock_init(&nn->writeverf_lock); @@ -1507,6 +1508,7 @@ static __net_exit void nfsd_exit_net(struct net *net) nfsd_idmap_shutdown(net); nfsd_export_shutdown(net); nfsd_netns_free_versions(net_generic(net, nfsd_net_id)); + nfsd4_leases_net_shutdown(nn); } static struct pernet_operations nfsd_net_ops = { diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h index 57a468ed85c3..7e05ab7a3532 100644 --- a/fs/nfsd/nfsd.h +++ b/fs/nfsd/nfsd.h @@ -498,7 +498,11 @@ extern void unregister_cld_notifier(void); extern void nfsd4_ssc_init_umount_work(struct nfsd_net *nn); #endif -extern void nfsd4_init_leases_net(struct nfsd_net *nn); +extern int nfsd4_init_leases_net(struct nfsd_net *nn); +static inline void nfsd4_leases_net_shutdown(struct nfsd_net *nn) +{ + unregister_shrinker(&nn->nfsd_client_shrinker); +}; #else /* CONFIG_NFSD_V4 */ static inline int nfsd4_is_junction(struct dentry *dentry) @@ -506,7 +510,8 @@ static inline int nfsd4_is_junction(struct dentry *dentry) return 0; } -static inline void nfsd4_init_leases_net(struct nfsd_net *nn) {}; +static inline int nfsd4_init_leases_net(struct nfsd_net *nn) { return 0; }; +static inline void nfsd4_leases_net_shutdown(struct nfsd_net *nn) { }; #define register_cld_notifier() 0 #define unregister_cld_notifier() do { } while(0)