From c83c2bee2dfa881007fa697ed912dd64574a0c3e Mon Sep 17 00:00:00 2001
From: yury <yury>
Date: Fri, 7 Nov 2008 22:37:57 +0000
Subject: [PATCH] b=17511 r=johann,adilger
- removes deadlock possibility by disabling rehash in hash_del() operations and moving hash_add()
out of spin_locks when calling. Hash table has own mechanisms for protecting its structures and it
also has hash_add_unique() method for using in concurrent run contexts;
- fixed missed lh_put() in hash_add_unique() which led to extra refs in some cases (extra ref to
export) and inability to cleanup;
- fixed __lustre_hash_set_theta() which set @max theta into ->lh_min_theta;
- in lustre_hash_rehash_size() disable rehash also for the case when new and old hash sizes equal
in corner cases (max_size or min_size). Before this fix it could be possible to do needless
rehashes when size is actually did not change but we do this expensive operation;
- disable rehash in hash_add_unique() if no actual add happened since entry with the same key is
already found in the table;
- some cleanups in hash table code;
---
lustre/include/class_hash.h | 6 ++---
lustre/ldlm/ldlm_flock.c | 3 +--
lustre/ldlm/ldlm_lib.c | 15 +++++--------
lustre/lov/lov_pool.c | 12 +++++-----
lustre/mdt/mdt_handler.c | 3 ++-
lustre/obdclass/class_hash.c | 43 ++++++++++++++++++------------------
6 files changed, 37 insertions(+), 45 deletions(-)
diff --git a/lustre/include/class_hash.h b/lustre/include/class_hash.h
index 70349cb092..e99efe84c4 100644
--- a/lustre/include/class_hash.h
+++ b/lustre/include/class_hash.h
@@ -242,8 +242,8 @@ void lustre_hash_exit(lustre_hash_t *lh);
*/
void lustre_hash_add(lustre_hash_t *lh, void *key,
struct hlist_node *hnode);
-int lustre_hash_add_unique(lustre_hash_t *lh, void *key,
- struct hlist_node *hnode);
+int lustre_hash_add_unique(lustre_hash_t *lh, void *key,
+ struct hlist_node *hnode);
void *lustre_hash_findadd_unique(lustre_hash_t *lh, void *key,
struct hlist_node *hnode);
@@ -284,7 +284,7 @@ __lustre_hash_set_theta(lustre_hash_t *lh, int min, int max)
{
LASSERT(min < max);
lh->lh_min_theta = min;
- lh->lh_min_theta = max;
+ lh->lh_max_theta = max;
}
/*
diff --git a/lustre/ldlm/ldlm_flock.c b/lustre/ldlm/ldlm_flock.c
index 2e888ffe2c..d38cfdff86 100644
--- a/lustre/ldlm/ldlm_flock.c
+++ b/lustre/ldlm/ldlm_flock.c
@@ -405,9 +405,8 @@ reprocess:
&new2->l_remote_handle,
&new2->l_exp_hash);
}
- if (*flags == LDLM_FL_WAIT_NOREPROC) {
+ if (*flags == LDLM_FL_WAIT_NOREPROC)
ldlm_lock_addref_internal_nolock(new2, lock->l_granted_mode);
- }
/* insert new2 at lock */
ldlm_resource_add_lock(res, ownlocks, new2);
diff --git a/lustre/ldlm/ldlm_lib.c b/lustre/ldlm/ldlm_lib.c
index 3431f63569..f6b0a4da38 100644
--- a/lustre/ldlm/ldlm_lib.c
+++ b/lustre/ldlm/ldlm_lib.c
@@ -910,16 +910,11 @@ dont_check_exports:
export->exp_connection = ptlrpc_connection_get(req->rq_peer,
req->rq_self,
&remote_uuid);
-
- spin_lock(&target->obd_dev_lock);
-
- /* Export might be hashed already, e.g. if this is reconnect */
- if (hlist_unhashed(&export->exp_nid_hash))
- lustre_hash_add(export->exp_obd->obd_nid_hash,
- &export->exp_connection->c_peer.nid,
- &export->exp_nid_hash);
-
- spin_unlock(&target->obd_dev_lock);
+ if (hlist_unhashed(&export->exp_nid_hash)) {
+ lustre_hash_add_unique(export->exp_obd->obd_nid_hash,
+ &export->exp_connection->c_peer.nid,
+ &export->exp_nid_hash);
+ }
spin_lock_bh(&target->obd_processing_task_lock);
if (target->obd_recovering && !export->exp_in_recovery) {
diff --git a/lustre/lov/lov_pool.c b/lustre/lov/lov_pool.c
index 12115ebd17..f63fac745b 100644
--- a/lustre/lov/lov_pool.c
+++ b/lustre/lov/lov_pool.c
@@ -400,18 +400,16 @@ int lov_pool_new(struct obd_device *obd, char *poolname)
GOTO(out_err, rc);
}
- spin_lock(&obd->obd_dev_lock);
- /* check if pool already exists */
- if (lustre_hash_lookup(lov->lov_pools_hash_body, poolname) != NULL) {
- spin_unlock(&obd->obd_dev_lock);
+ INIT_HLIST_NODE(&new_pool->pool_hash);
+ rc = lustre_hash_add_unique(lov->lov_pools_hash_body, poolname,
+ &new_pool->pool_hash);
+ if (rc) {
lov_ost_pool_free(&new_pool->pool_rr.lqr_pool);
lov_ost_pool_free(&new_pool->pool_obds);
GOTO(out_err, rc = -EEXIST);
}
- INIT_HLIST_NODE(&new_pool->pool_hash);
- lustre_hash_add_unique(lov->lov_pools_hash_body, poolname,
- &new_pool->pool_hash);
+ spin_lock(&obd->obd_dev_lock);
list_add_tail(&new_pool->pool_list, &lov->lov_pool_list);
lov->lov_pool_count++;
spin_unlock(&obd->obd_dev_lock);
diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index ffdc67c158..91943141d5 100644
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -2885,11 +2885,12 @@ int mdt_intent_lock_replace(struct mdt_thread_info *info,
new_lock->l_remote_handle = lock->l_remote_handle;
new_lock->l_flags &= ~LDLM_FL_LOCAL;
+ unlock_res_and_lock(new_lock);
+
lustre_hash_add(new_lock->l_export->exp_lock_hash,
&new_lock->l_remote_handle,
&new_lock->l_exp_hash);
- unlock_res_and_lock(new_lock);
LDLM_LOCK_RELEASE(new_lock);
lh->mlh_reg_lh.cookie = 0;
diff --git a/lustre/obdclass/class_hash.c b/lustre/obdclass/class_hash.c
index 0dd18f137d..ee90aaf3cb 100644
--- a/lustre/obdclass/class_hash.c
+++ b/lustre/obdclass/class_hash.c
@@ -95,11 +95,12 @@ lustre_hash_init(char *name, unsigned int cur_size, unsigned int max_size,
lh->lh_cur_size = cur_size;
lh->lh_min_size = cur_size;
lh->lh_max_size = max_size;
- lh->lh_min_theta = 500; /* theta * 1000 */
- lh->lh_max_theta = 2000; /* theta * 1000 */
lh->lh_ops = ops;
lh->lh_flags = flags;
+ /* theta * 1000 */
+ __lustre_hash_set_theta(lh, 500, 2000);
+
OBD_VMALLOC(lh->lh_buckets, sizeof(*lh->lh_buckets) * lh->lh_cur_size);
if (!lh->lh_buckets) {
OBD_FREE_PTR(lh);
@@ -156,18 +157,24 @@ EXPORT_SYMBOL(lustre_hash_exit);
static inline unsigned int lustre_hash_rehash_size(lustre_hash_t *lh)
{
+ int size;
+
if (!(lh->lh_flags & LH_REHASH))
return 0;
if ((lh->lh_cur_size < lh->lh_max_size) &&
(__lustre_hash_theta(lh) > lh->lh_max_theta))
- return MIN(lh->lh_cur_size * 2, lh->lh_max_size);
-
- if ((lh->lh_cur_size > lh->lh_min_size) &&
+ size = min(lh->lh_cur_size * 2, lh->lh_max_size);
+ else if ((lh->lh_cur_size > lh->lh_min_size) &&
(__lustre_hash_theta(lh) < lh->lh_min_theta))
- return MAX(lh->lh_cur_size / 2, lh->lh_min_size);
+ size = max(lh->lh_cur_size / 2, lh->lh_min_size);
+ else
+ size = 0;
- return 0;
+ if (lh->lh_cur_size == size)
+ size = 0;
+
+ return size;
}
/**
@@ -207,9 +214,9 @@ static struct hlist_node *
lustre_hash_findadd_unique_hnode(lustre_hash_t *lh, void *key,
struct hlist_node *hnode)
{
+ int size = 0;
struct hlist_node *ehnode;
lustre_hash_bucket_t *lhb;
- int size;
unsigned i;
ENTRY;
@@ -228,10 +235,9 @@ lustre_hash_findadd_unique_hnode(lustre_hash_t *lh, void *key,
} else {
__lustre_hash_bucket_add(lh, lhb, hnode);
ehnode = hnode;
+ size = lustre_hash_rehash_size(lh);
}
write_unlock(&lhb->lhb_rwlock);
-
- size = lustre_hash_rehash_size(lh);
read_unlock(&lh->lh_rwlock);
if (size)
lustre_hash_rehash(lh, size);
@@ -251,8 +257,10 @@ lustre_hash_add_unique(lustre_hash_t *lh, void *key, struct hlist_node *hnode)
ENTRY;
ehnode = lustre_hash_findadd_unique_hnode(lh, key, hnode);
- if (ehnode != hnode)
+ if (ehnode != hnode) {
+ lh_put(lh, ehnode);
RETURN(-EALREADY);
+ }
RETURN(0);
}
@@ -290,7 +298,6 @@ void *
lustre_hash_del(lustre_hash_t *lh, void *key, struct hlist_node *hnode)
{
lustre_hash_bucket_t *lhb;
- int size;
unsigned i;
void *obj;
ENTRY;
@@ -306,11 +313,7 @@ lustre_hash_del(lustre_hash_t *lh, void *key, struct hlist_node *hnode)
write_lock(&lhb->lhb_rwlock);
obj = __lustre_hash_bucket_del(lh, lhb, hnode);
write_unlock(&lhb->lhb_rwlock);
-
- size = lustre_hash_rehash_size(lh);
read_unlock(&lh->lh_rwlock);
- if (size)
- lustre_hash_rehash(lh, size);
RETURN(obj);
}
@@ -327,7 +330,6 @@ lustre_hash_del_key(lustre_hash_t *lh, void *key)
{
struct hlist_node *hnode;
lustre_hash_bucket_t *lhb;
- int size;
unsigned i;
void *obj = NULL;
ENTRY;
@@ -343,11 +345,7 @@ lustre_hash_del_key(lustre_hash_t *lh, void *key)
obj = __lustre_hash_bucket_del(lh, lhb, hnode);
write_unlock(&lhb->lhb_rwlock);
-
- size = lustre_hash_rehash_size(lh);
read_unlock(&lh->lh_rwlock);
- if (size)
- lustre_hash_rehash(lh, size);
RETURN(obj);
}
@@ -499,7 +497,7 @@ restart:
}
EXPORT_SYMBOL(lustre_hash_for_each_empty);
- /*
+/**
* For each item in the lustre hash @lh which matches the @key call
* the passed callback @func and pass to it as an argument each hash
* item and the private @data. Before each callback ops->lh_get will
@@ -566,6 +564,7 @@ lustre_hash_rehash(lustre_hash_t *lh, int size)
ENTRY;
LASSERT(size > 0);
+ LASSERT(!in_interrupt());
OBD_VMALLOC(rehash_buckets, sizeof(*rehash_buckets) * size);
if (!rehash_buckets)
--
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