2022-07-25 9:48 GMT+09:00, Hyunchul Lee <hyc.lee@xxxxxxxxx>:
> 2022년 7월 22일 (금) 오후 12:04, Namjae Jeon <linkinjeon@xxxxxxxxxx>님이 작성:
>>
>> ksmbd threads eating masses of cputime when connection is disconnected.
>> If connection is disconnected, ksmbd thread waits for pending requests
>> to be processed using schedule_timeout. schedule_timeout() incorrectly
>> is used, and it is more efficient to use wait_event/wake_up than to check
>> r_count every time with timeout.
>>
>> Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
>> ---
>> fs/ksmbd/connection.c | 6 +++---
>> fs/ksmbd/connection.h | 1 +
>> fs/ksmbd/oplock.c | 21 ++++++++++-----------
>> fs/ksmbd/server.c | 1 +
>> 4 files changed, 15 insertions(+), 14 deletions(-)
>>
>> diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c
>> index ce23cc89046e..756ad631c019 100644
>> --- a/fs/ksmbd/connection.c
>> +++ b/fs/ksmbd/connection.c
>> @@ -66,6 +66,7 @@ struct ksmbd_conn *ksmbd_conn_alloc(void)
>> conn->outstanding_credits = 0;
>>
>> init_waitqueue_head(&conn->req_running_q);
>> + init_waitqueue_head(&conn->r_count_q);
>> INIT_LIST_HEAD(&conn->conns_list);
>> INIT_LIST_HEAD(&conn->requests);
>> INIT_LIST_HEAD(&conn->async_requests);
>> @@ -165,7 +166,6 @@ int ksmbd_conn_write(struct ksmbd_work *work)
>> struct kvec iov[3];
>> int iov_idx = 0;
>>
>> - ksmbd_conn_try_dequeue_request(work);
>> if (!work->response_buf) {
>> pr_err("NULL response header\n");
>> return -EINVAL;
>> @@ -347,8 +347,8 @@ int ksmbd_conn_handler_loop(void *p)
>>
>> out:
>> /* Wait till all reference dropped to the Server object*/
>> - while (atomic_read(&conn->r_count) > 0)
>> - schedule_timeout(HZ);
>> + wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);
>> +
>>
>> unload_nls(conn->local_nls);
>> if (default_conn_ops.terminate_fn)
>> diff --git a/fs/ksmbd/connection.h b/fs/ksmbd/connection.h
>> index 5b39f0bdeff8..2e4730457c92 100644
>> --- a/fs/ksmbd/connection.h
>> +++ b/fs/ksmbd/connection.h
>> @@ -65,6 +65,7 @@ struct ksmbd_conn {
>> unsigned int outstanding_credits;
>> spinlock_t credits_lock;
>> wait_queue_head_t req_running_q;
>> + wait_queue_head_t r_count_q;
>> /* Lock to protect requests list*/
>> spinlock_t request_lock;
>> struct list_head requests;
>> diff --git a/fs/ksmbd/oplock.c b/fs/ksmbd/oplock.c
>> index 8b5560574d4c..9bb4fb8b80de 100644
>> --- a/fs/ksmbd/oplock.c
>> +++ b/fs/ksmbd/oplock.c
>> @@ -615,18 +615,13 @@ static void __smb2_oplock_break_noti(struct
>> work_struct *wk)
>> struct ksmbd_file *fp;
>>
>> fp = ksmbd_lookup_durable_fd(br_info->fid);
>> - if (!fp) {
>> - atomic_dec(&conn->r_count);
>> - ksmbd_free_work_struct(work);
>> - return;
>> - }
>> + if (!fp)
>> + goto out;
>>
>> if (allocate_oplock_break_buf(work)) {
>> pr_err("smb2_allocate_rsp_buf failed! ");
>> - atomic_dec(&conn->r_count);
>> ksmbd_fd_put(work, fp);
>> - ksmbd_free_work_struct(work);
>> - return;
>> + goto out;
>> }
>>
>> rsp_hdr = smb2_get_msg(work->response_buf);
>> @@ -667,8 +662,11 @@ static void __smb2_oplock_break_noti(struct
>> work_struct *wk)
>>
>> ksmbd_fd_put(work, fp);
>> ksmbd_conn_write(work);
>> +
>> +out:
>> ksmbd_free_work_struct(work);
>> atomic_dec(&conn->r_count);
>> + wake_up_all(&conn->r_count_q);
>
> I think calling wake_up_all is better if atomic_dec_return(&conn->r_count)
> == 0.
Are there cases where r_count inc/dec doesn't pair?
> Otherwise, Looks good to me.
>
>> }
>>
>> /**
>> @@ -731,9 +729,7 @@ static void __smb2_lease_break_noti(struct work_struct
>> *wk)
>>
>> if (allocate_oplock_break_buf(work)) {
>> ksmbd_debug(OPLOCK, "smb2_allocate_rsp_buf failed! ");
>> - ksmbd_free_work_struct(work);
>> - atomic_dec(&conn->r_count);
>> - return;
>> + goto out;
>> }
>>
>> rsp_hdr = smb2_get_msg(work->response_buf);
>> @@ -771,8 +767,11 @@ static void __smb2_lease_break_noti(struct
>> work_struct *wk)
>> inc_rfc1001_len(work->response_buf, 44);
>>
>> ksmbd_conn_write(work);
>> +
>> +out:
>> ksmbd_free_work_struct(work);
>> atomic_dec(&conn->r_count);
>> + wake_up_all(&conn->r_count_q);
>> }
>>
>> /**
>> diff --git a/fs/ksmbd/server.c b/fs/ksmbd/server.c
>> index 4cd03d661df0..dfddc8dc1919 100644
>> --- a/fs/ksmbd/server.c
>> +++ b/fs/ksmbd/server.c
>> @@ -262,6 +262,7 @@ static void handle_ksmbd_work(struct work_struct *wk)
>> ksmbd_conn_try_dequeue_request(work);
>> ksmbd_free_work_struct(work);
>> atomic_dec(&conn->r_count);
>> + wake_up_all(&conn->r_count_q);
>> }
>>
>> /**
>> --
>> 2.25.1
>>
>
>
> --
> Thanks,
> Hyunchul
>
