From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Aring Date: Fri, 24 Sep 2021 20:30:13 -0400 Subject: [Cluster-devel] [PATCH dlm/next 3/5] fs: dlm: requestqueue busy wait to event based wait In-Reply-To: <20210925003015.1862586-1-aahringo@redhat.com> References: <20210925003015.1862586-1-aahringo@redhat.com> Message-ID: <20210925003015.1862586-3-aahringo@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit This patch changes the requestqueue busy waiting algorithm to use atomic counter values and wait_event() to wait until the requestqueue is empty. It will slightly reduce the number of holding ls_requestqueue_mutex mutex. Signed-off-by: Alexander Aring --- fs/dlm/dlm_internal.h | 2 ++ fs/dlm/lockspace.c | 2 ++ fs/dlm/requestqueue.c | 15 +++++++-------- 3 files changed, 11 insertions(+), 8 deletions(-) diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h index de6c9fb5dd30..fc6505067c80 100644 --- a/fs/dlm/dlm_internal.h +++ b/fs/dlm/dlm_internal.h @@ -632,6 +632,8 @@ struct dlm_ls { struct rw_semaphore ls_in_recovery; /* block local requests */ struct rw_semaphore ls_recv_active; /* block dlm_recv */ struct list_head ls_requestqueue;/* queue remote requests */ + atomic_t ls_requestqueue_cnt; + wait_queue_head_t ls_requestqueue_wait; struct mutex ls_requestqueue_mutex; struct dlm_rcom *ls_recover_buf; int ls_recover_nodeid; /* for debugging */ diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c index 353a0ee21467..de1c4af5eb8c 100644 --- a/fs/dlm/lockspace.c +++ b/fs/dlm/lockspace.c @@ -564,6 +564,8 @@ static int new_lockspace(const char *name, const char *cluster, init_rwsem(&ls->ls_in_recovery); init_rwsem(&ls->ls_recv_active); INIT_LIST_HEAD(&ls->ls_requestqueue); + atomic_set(&ls->ls_requestqueue_cnt, 0); + init_waitqueue_head(&ls->ls_requestqueue_wait); mutex_init(&ls->ls_requestqueue_mutex); mutex_init(&ls->ls_clear_proc_locks); diff --git a/fs/dlm/requestqueue.c b/fs/dlm/requestqueue.c index e89e0ff8bfa3..d0cf68570dcf 100644 --- a/fs/dlm/requestqueue.c +++ b/fs/dlm/requestqueue.c @@ -44,6 +44,7 @@ void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_message *ms) e->nodeid = nodeid; memcpy(&e->request, ms, ms->m_header.h_length); + atomic_inc(&ls->ls_requestqueue_cnt); mutex_lock(&ls->ls_requestqueue_mutex); list_add_tail(&e->list, &ls->ls_requestqueue); mutex_unlock(&ls->ls_requestqueue_mutex); @@ -89,6 +90,8 @@ int dlm_process_requestqueue(struct dlm_ls *ls) mutex_lock(&ls->ls_requestqueue_mutex); list_del(&e->list); + if (atomic_dec_and_test(&ls->ls_requestqueue_cnt)) + wake_up(&ls->ls_requestqueue_wait); kfree(e); if (dlm_locking_stopped(ls)) { @@ -115,14 +118,8 @@ int dlm_process_requestqueue(struct dlm_ls *ls) void dlm_wait_requestqueue(struct dlm_ls *ls) { - for (;;) { - mutex_lock(&ls->ls_requestqueue_mutex); - if (list_empty(&ls->ls_requestqueue)) - break; - mutex_unlock(&ls->ls_requestqueue_mutex); - schedule(); - } - mutex_unlock(&ls->ls_requestqueue_mutex); + wait_event(ls->ls_requestqueue_wait, + atomic_read(&ls->ls_requestqueue_cnt) == 0); } static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid) @@ -161,6 +158,8 @@ void dlm_purge_requestqueue(struct dlm_ls *ls) if (purge_request(ls, ms, e->nodeid)) { list_del(&e->list); + if (atomic_dec_and_test(&ls->ls_requestqueue_cnt)) + wake_up(&ls->ls_requestqueue_wait); kfree(e); } } -- 2.27.0