android/android_kernel_samsung_sm8650
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fs: dlm: requestqueue busy wait to event based wait

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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 <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This commit is contained in:
Alexander Aring 2021-11-02 15:17:17 -04:00 committed by David Teigland
parent 92732376fd
commit 164d88abd7
3 changed files with 11 additions and 8 deletions
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2
fs/dlm/dlm_internal.h
View File

@ -626,6 +626,8 @@ 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 */

2
fs/dlm/lockspace.c
View File

@ -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);

15
fs/dlm/requestqueue.c
View File

@ -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);
}
}