5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dai Ngo dai.ngo@oracle.com
[ Upstream commit 7746b32f467b3813fb61faaab3258de35806a7ac ]
Add courtesy_client_reaper to react to low memory condition triggered by the system memory shrinker.
The delayed_work for the courtesy_client_reaper is scheduled on the shrinker's count callback using the laundry_wq.
The shrinker's scan callback is not used for expiring the courtesy clients due to potential deadlocks.
Signed-off-by: Dai Ngo dai.ngo@oracle.com Signed-off-by: Chuck Lever chuck.lever@oracle.com --- fs/nfsd/netns.h | 2 + fs/nfsd/nfs4state.c | 94 +++++++++++++++++++++++++++++++++++++++++---- fs/nfsd/nfsctl.c | 6 ++- fs/nfsd/nfsd.h | 6 ++- 4 files changed, 96 insertions(+), 12 deletions(-)
diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h index 55c7006d6109a..8c854ba3285bb 100644 --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -194,6 +194,8 @@ struct nfsd_net { int nfs4_max_clients;
atomic_t nfsd_courtesy_clients; + struct shrinker nfsd_client_shrinker; + struct delayed_work nfsd_shrinker_work; };
/* 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 6a7a99511111d..8cbb66b07d519 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4366,7 +4366,27 @@ 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) +{ + int cnt; + struct nfsd_net *nn = container_of(shrink, + struct nfsd_net, nfsd_client_shrinker); + + cnt = atomic_read(&nn->nfsd_courtesy_clients); + if (cnt > 0) + mod_delayed_work(laundry_wq, &nn->nfsd_shrinker_work, 0); + return (unsigned long)cnt; +} + +static unsigned long +nfsd_courtesy_client_scan(struct shrinker *shrink, struct shrink_control *sc) +{ + return SHRINK_STOP; +} + +int +nfsd4_init_leases_net(struct nfsd_net *nn) { struct sysinfo si; u64 max_clients; @@ -4387,6 +4407,16 @@ 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_clients, 0); + 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); +} + +void +nfsd4_leases_net_shutdown(struct nfsd_net *nn) +{ + unregister_shrinker(&nn->nfsd_client_shrinker); }
static void init_nfs4_replay(struct nfs4_replay *rp) @@ -5959,10 +5989,49 @@ nfs4_get_client_reaplist(struct nfsd_net *nn, struct list_head *reaplist, spin_unlock(&nn->client_lock); }
+static void +nfs4_get_courtesy_client_reaplist(struct nfsd_net *nn, + struct list_head *reaplist) +{ + unsigned int maxreap = 0, reapcnt = 0; + struct list_head *pos, *next; + struct nfs4_client *clp; + + maxreap = NFSD_CLIENT_MAX_TRIM_PER_RUN; + INIT_LIST_HEAD(reaplist); + + spin_lock(&nn->client_lock); + list_for_each_safe(pos, next, &nn->client_lru) { + clp = list_entry(pos, struct nfs4_client, cl_lru); + if (clp->cl_state == NFSD4_ACTIVE) + break; + if (reapcnt >= maxreap) + break; + if (!mark_client_expired_locked(clp)) { + list_add(&clp->cl_lru, reaplist); + reapcnt++; + } + } + spin_unlock(&nn->client_lock); +} + +static void +nfs4_process_client_reaplist(struct list_head *reaplist) +{ + struct list_head *pos, *next; + struct nfs4_client *clp; + + list_for_each_safe(pos, next, reaplist) { + clp = list_entry(pos, struct nfs4_client, cl_lru); + trace_nfsd_clid_purged(&clp->cl_clientid); + list_del_init(&clp->cl_lru); + expire_client(clp); + } +} + static time64_t nfs4_laundromat(struct nfsd_net *nn) { - struct nfs4_client *clp; struct nfs4_openowner *oo; struct nfs4_delegation *dp; struct nfs4_ol_stateid *stp; @@ -5991,12 +6060,8 @@ nfs4_laundromat(struct nfsd_net *nn) } spin_unlock(&nn->s2s_cp_lock); nfs4_get_client_reaplist(nn, &reaplist, <); - list_for_each_safe(pos, next, &reaplist) { - clp = list_entry(pos, struct nfs4_client, cl_lru); - trace_nfsd_clid_purged(&clp->cl_clientid); - list_del_init(&clp->cl_lru); - expire_client(clp); - } + nfs4_process_client_reaplist(&reaplist); + spin_lock(&state_lock); list_for_each_safe(pos, next, &nn->del_recall_lru) { dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru); @@ -6079,6 +6144,18 @@ laundromat_main(struct work_struct *laundry) queue_delayed_work(laundry_wq, &nn->laundromat_work, t*HZ); }
+static void +courtesy_client_reaper(struct work_struct *reaper) +{ + struct list_head reaplist; + struct delayed_work *dwork = to_delayed_work(reaper); + struct nfsd_net *nn = container_of(dwork, struct nfsd_net, + nfsd_shrinker_work); + + nfs4_get_courtesy_client_reaplist(nn, &reaplist); + nfs4_process_client_reaplist(&reaplist); +} + static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stid *stp) { if (!fh_match(&fhp->fh_handle, &stp->sc_file->fi_fhandle)) @@ -7897,6 +7974,7 @@ static int nfs4_state_create_net(struct net *net) INIT_LIST_HEAD(&nn->blocked_locks_lru);
INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main); + INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, courtesy_client_reaper); get_net(net);
return 0; diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 917fa1892fd2d..597a26ad4183f 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 6ab4ad41ae84e..09726c5b9a317 100644 --- a/fs/nfsd/nfsd.h +++ b/fs/nfsd/nfsd.h @@ -505,7 +505,8 @@ 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); +extern void nfsd4_leases_net_shutdown(struct nfsd_net *nn);
#else /* CONFIG_NFSD_V4 */ static inline int nfsd4_is_junction(struct dentry *dentry) @@ -513,7 +514,8 @@ 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)