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ksmbd: use wait_event instead of schedule_timeout()

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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@kernel.org>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Namjae Jeon 2022-07-28 23:35:18 +09:00 committed by Steve French
parent 17ea92a9f6
commit a14c573870
4 changed files with 33 additions and 17 deletions
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6
fs/ksmbd/connection.c
View File

@ -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)

1
fs/ksmbd/connection.h
View File

@ -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;

35
fs/ksmbd/oplock.c
View File

@ -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 +662,16 @@ 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);
/*
* Checking waitqueue to dropping pending requests on
* disconnection. waitqueue_active is safe because it
* uses atomic operation for condition.
*/
if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
wake_up(&conn->r_count_q);
}
/**
@ -731,9 +734,7 @@ 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 +772,16 @@ 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);
/*
* Checking waitqueue to dropping pending requests on
* disconnection. waitqueue_active is safe because it
* uses atomic operation for condition.
*/
if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
wake_up(&conn->r_count_q);
}
/**

8
fs/ksmbd/server.c
View File

@ -261,7 +261,13 @@ 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);
/*
* Checking waitqueue to dropping pending requests on
* disconnection. waitqueue_active is safe because it
* uses atomic operation for condition.
*/
if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
wake_up(&conn->r_count_q);
}
/**