From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Simmons Date: Thu, 27 Feb 2020 16:17:14 -0500 Subject: [lustre-devel] [PATCH 566/622] lustre: ldlm: add a counter to the per-namespace data In-Reply-To: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> References: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> Message-ID: <1582838290-17243-567-git-send-email-jsimmons@infradead.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org From: NeilBrown When we change the resource hash to rhashtable we won't have a per-bucket counter. We could use the nelems global counter, but ldlm_resource goes to some trouble to avoid having any table-wide atomics, and hopefully rhashtable will grow the ability to disable the global counter in the near future. Having a counter we control makes it easier to manage the back-reference to the namespace when there is anything in the hash table. So add a counter to the ldlm_ns_bucket. WC-bug-id: https://jira.whamcloud.com/browse/LU-8130 Lustre-commit: f9314d6e9259e6c7 ("LU-8130 ldlm: add a counter to the per-namespace data") Signed-off-by: NeilBrown Reviewed-on: https://review.whamcloud.com/36219 Reviewed-by: Neil Brown Reviewed-by: Shaun Tancheff Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- fs/lustre/include/lustre_dlm.h | 2 ++ fs/lustre/ldlm/ldlm_resource.c | 10 +++++----- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/lustre/include/lustre_dlm.h b/fs/lustre/include/lustre_dlm.h index cc4b8b0..9ca79f4 100644 --- a/fs/lustre/include/lustre_dlm.h +++ b/fs/lustre/include/lustre_dlm.h @@ -306,6 +306,8 @@ struct ldlm_ns_bucket { * fact the network or overall system load is at fault */ struct adaptive_timeout nsb_at_estimate; + /* counter of entries in this bucket */ + atomic_t nsb_count; }; enum { diff --git a/fs/lustre/ldlm/ldlm_resource.c b/fs/lustre/ldlm/ldlm_resource.c index 65ff32c..d009d5d 100644 --- a/fs/lustre/ldlm/ldlm_resource.c +++ b/fs/lustre/ldlm/ldlm_resource.c @@ -133,12 +133,11 @@ static ssize_t resource_count_show(struct kobject *kobj, struct attribute *attr, struct ldlm_namespace *ns = container_of(kobj, struct ldlm_namespace, ns_kobj); u64 res = 0; - struct cfs_hash_bd bd; int i; /* result is not strictly consistent */ - cfs_hash_for_each_bucket(ns->ns_rs_hash, &bd, i) - res += cfs_hash_bd_count_get(&bd); + for (i = 0; i < (1 << ns->ns_bucket_bits); i++) + res += atomic_read(&ns->ns_rs_buckets[i].nsb_count); return sprintf(buf, "%lld\n", res); } LUSTRE_RO_ATTR(resource_count); @@ -647,6 +646,7 @@ struct ldlm_namespace *ldlm_namespace_new(struct obd_device *obd, char *name, at_init(&nsb->nsb_at_estimate, ldlm_enqueue_min, 0); nsb->nsb_namespace = ns; + atomic_set(&nsb->nsb_count, 0); } ns->ns_obd = obd; @@ -1126,7 +1126,7 @@ struct ldlm_resource * } /* We won! Let's add the resource. */ cfs_hash_bd_add_locked(ns->ns_rs_hash, &bd, &res->lr_hash); - if (cfs_hash_bd_count_get(&bd) == 1) + if (atomic_inc_return(&res->lr_ns_bucket->nsb_count) == 1) ns_refcount = ldlm_namespace_get_return(ns); cfs_hash_bd_unlock(ns->ns_rs_hash, &bd, 1); @@ -1170,7 +1170,7 @@ static void __ldlm_resource_putref_final(struct cfs_hash_bd *bd, cfs_hash_bd_unlock(ns->ns_rs_hash, bd, 1); if (ns->ns_lvbo && ns->ns_lvbo->lvbo_free) ns->ns_lvbo->lvbo_free(res); - if (cfs_hash_bd_count_get(bd) == 0) + if (atomic_dec_and_test(&nsb->nsb_count)) ldlm_namespace_put(ns); if (res->lr_itree) kmem_cache_free(ldlm_interval_tree_slab, res->lr_itree); -- 1.8.3.1