LU-16062 ldlm: improve bl_timeout for prolong

If there is a client's RPC in hand, we can do a better job for
calculating the lock callback timeout as RPC has the info what
client thinks about this RPC timeout. Let's use it.

Lustre-change: https://review.whamcloud.com/48094
Lustre-commit: 34b2246e4a6c8ce827c404cb4e52f7c6a0a1b90b

HPE-bug-id: LUS-8866, LUS-11074
Signed-off-by: Vitaly Fertman <c17818@cray.com>
Change-Id: Ibd67d37c1073d0d3cb2e08b532c801af0de116fe
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/48762
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lustre/include/lustre_dlm.h b/lustre/include/lustre_dlm.h
index 795c5ff..4bd273e 100644 (file)
--- a/lustre/include/lustre_dlm.h
+++ b/lustre/include/lustre_dlm.h
@@ -1397,10 +1397,10 @@ __u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms);
 
 struct ldlm_prolong_args {
        struct obd_export       *lpa_export;
+       struct ptlrpc_request   *lpa_req;
        struct ldlm_res_id      lpa_resid;
        struct ldlm_extent      lpa_extent;
        enum ldlm_mode          lpa_mode;
-       timeout_t               lpa_timeout;
        int                     lpa_locks_cnt;
        int                     lpa_blocks_cnt;
 };
@@ -1447,6 +1447,7 @@ int ldlm_request_cancel(struct ptlrpc_request *req,
 
 void ldlm_revoke_export_locks(struct obd_export *exp);
 timeout_t ldlm_bl_timeout(struct ldlm_lock *lock);
+timeout_t ldlm_bl_timeout_by_rpc(struct ptlrpc_request *req);
 #endif
 int ldlm_del_waiting_lock(struct ldlm_lock *lock);
 int ldlm_refresh_waiting_lock(struct ldlm_lock *lock, timeout_t timeout);

diff --git a/lustre/include/lustre_net.h b/lustre/include/lustre_net.h
index 1d94c3e..e71b936 100644 (file)
--- a/lustre/include/lustre_net.h
+++ b/lustre/include/lustre_net.h
@@ -2545,30 +2545,6 @@ ptlrpc_server_get_timeout(struct ptlrpc_service_part *svcpt)
               max_t(int, at, obd_timeout);
 }
 
-/**
- * Calculate the amount of time for lock prolongation.
- *
- * This is helper function to get the timeout extra time.
- *
- * @req                current request
- *
- * Return:     amount of time to extend the timeout with
- */
-static inline timeout_t prolong_timeout(struct ptlrpc_request *req)
-{
-       struct ptlrpc_service_part *svcpt = req->rq_rqbd->rqbd_svcpt;
-       timeout_t req_timeout = 0;
-
-       if (AT_OFF)
-               return obd_timeout / 2;
-
-       if (req->rq_deadline > req->rq_arrival_time.tv_sec)
-               req_timeout = req->rq_deadline - req->rq_arrival_time.tv_sec;
-
-       return max(req_timeout,
-                  at_est2timeout(at_get(&svcpt->scp_at_estimate)));
-}
-
 static inline struct ptlrpc_service *
 ptlrpc_req2svc(struct ptlrpc_request *req)
 {

diff --git a/lustre/ldlm/ldlm_extent.c b/lustre/ldlm/ldlm_extent.c
index b350708..993193a 100644 (file)
--- a/lustre/ldlm/ldlm_extent.c
+++ b/lustre/ldlm/ldlm_extent.c
@@ -652,16 +652,13 @@ void ldlm_lock_prolong_one(struct ldlm_lock *lock,
                /* ignore locks not being cancelled */
                return;
 
-       /* We are in the middle of the process - BL AST is sent, CANCEL
-        * is ahead. Take half of BL AT + IO AT process time.
-        */
-       timeout = arg->lpa_timeout + (ldlm_bl_timeout(lock) >> 1);
-
        arg->lpa_blocks_cnt++;
 
        /* OK. this is a possible lock the user holds doing I/O
         * let's refresh eviction timer for it.
         */
+       timeout = ldlm_bl_timeout_by_rpc(arg->lpa_req);
+       LDLM_DEBUG(lock, "refreshed to %ds.\n", timeout);
        ldlm_refresh_waiting_lock(lock, timeout);
 }
 EXPORT_SYMBOL(ldlm_lock_prolong_one);

diff --git a/lustre/ldlm/ldlm_lockd.c b/lustre/ldlm/ldlm_lockd.c
index 52c69e0..7ecb280 100644 (file)
--- a/lustre/ldlm/ldlm_lockd.c
+++ b/lustre/ldlm/ldlm_lockd.c
@@ -648,6 +648,54 @@ timeout_t ldlm_bl_timeout(struct ldlm_lock *lock)
 EXPORT_SYMBOL(ldlm_bl_timeout);
 
 /**
+ * Calculate the per-export Blocking timeout by the given RPC (covering the
+ * reply to this RPC and the next RPC). The next RPC could be still not CANCEL,
+ * but having the lock refresh mechanism it is enough.
+ *
+ * Used for lock refresh timeout when we are in the middle of the process -
+ * BL AST is sent, CANCEL is ahead - it is still 1 reply for the current RPC
+ * and at least 1 RPC (which will trigger another refresh if it will be not
+ * CANCEL) - but more accurate than ldlm_bl_timeout as the timeout is taken
+ * from the RPC (i.e. the view of the client on the current AT) is taken into
+ * account.
+ *
+ * \param[in] req     req which export needs the timeout calculation
+ *
+ * \retval            timeout in seconds to wait for the next client's RPC
+ */
+timeout_t ldlm_bl_timeout_by_rpc(struct ptlrpc_request *req)
+{
+       struct ptlrpc_service_part *svcpt = req->rq_rqbd->rqbd_svcpt;
+       timeout_t timeout, req_timeout, at_timeout, netl;
+
+       if (AT_OFF)
+               return obd_timeout / 2;
+
+       /* A blocked lock means somebody in the cluster is waiting, and we
+        * should not consider the worst ever case, consisting of a chain of
+        * failures on each step, however this timeout should survive a
+        * recovery of at least 1 failure, let this one to be the worst one:
+        * in case a server NID is dead first re-connect is done through the
+        * same router and also times out.
+        *
+        * Either this on the next RPC times out, take the max.
+        * Considering the current RPC, take just the left time.
+        */
+       netl = at_get(&req->rq_export->exp_imp_reverse->imp_at.iat_net_latency);
+       req_timeout = req->rq_deadline - ktime_get_real_seconds() + netl;
+       at_timeout = at_est2timeout(at_get(&svcpt->scp_at_estimate)) + netl;
+       req_timeout = max(req_timeout, at_timeout);
+
+       /* Take 1 re-connect failure and 1 re-connect success into account. */
+       timeout = at_timeout + INITIAL_CONNECT_TIMEOUT + netl + req_timeout;
+
+       /* Client's timeout is calculated as at_est2timeout(), let's be a bit
+        * more conservative than client */
+       return max(timeout + (timeout >> 4), (timeout_t)ldlm_enqueue_min);
+}
+EXPORT_SYMBOL(ldlm_bl_timeout_by_rpc);
+
+/**
  * Perform lock cleanup if AST sending failed.
  */
 static void ldlm_failed_ast(struct ldlm_lock *lock, int rc,

diff --git a/lustre/mdt/mdt_io.c b/lustre/mdt/mdt_io.c
index 799d117..d09b555 100644 (file)
--- a/lustre/mdt/mdt_io.c
+++ b/lustre/mdt/mdt_io.c
@@ -98,7 +98,7 @@ static void mdt_prolong_dom_lock(struct tgt_session_info *tsi,
 
        ENTRY;
 
-       data->lpa_timeout = prolong_timeout(tgt_ses_req(tsi));
+       data->lpa_req = tgt_ses_req(tsi);
        data->lpa_export = tsi->tsi_exp;
        data->lpa_resid = tsi->tsi_resid;
 

diff --git a/lustre/ofd/ofd_dev.c b/lustre/ofd/ofd_dev.c
index 38292a7..ae59348 100644 (file)
--- a/lustre/ofd/ofd_dev.c
+++ b/lustre/ofd/ofd_dev.c
@@ -2461,7 +2461,7 @@ static void ofd_prolong_extent_locks(struct tgt_session_info *tsi,
 
        ENTRY;
 
-       data->lpa_timeout = prolong_timeout(tgt_ses_req(tsi));
+       data->lpa_req = tgt_ses_req(tsi);
        data->lpa_export = tsi->tsi_exp;
        data->lpa_resid = tsi->tsi_resid;