LU-56 ptlrpc: common code to validate nthreads

[fs/lustre-release.git] / lustre / ptlrpc / service.c

diff --git a/lustre/ptlrpc/service.c b/lustre/ptlrpc/service.c
index ffe84a1..d807e49 100644 (file)
--- a/lustre/ptlrpc/service.c
+++ b/lustre/ptlrpc/service.c
@@ -445,6 +445,53 @@ static void ptlrpc_at_timer(unsigned long castmeharder)
         cfs_waitq_signal(&svc->srv_waitq);
 }
 
+static void
+ptlrpc_server_nthreads_check(struct ptlrpc_service_conf *conf,
+                            int *min_p, int *max_p)
+{
+#ifdef __KERNEL__
+       struct ptlrpc_service_thr_conf  *tc = &conf->psc_thr;
+       int                             nthrs_min;
+       int                             nthrs;
+
+       nthrs_min = PTLRPC_NTHRS_MIN + (conf->psc_ops.so_hpreq_handler != NULL);
+       nthrs_min = max_t(int, nthrs_min, tc->tc_nthrs_min);
+
+       nthrs = tc->tc_nthrs_user;
+       if (nthrs != 0) { /* validate it */
+               nthrs = min_t(int, nthrs, tc->tc_nthrs_max);
+               nthrs = max_t(int, nthrs, nthrs_min);
+               *min_p = *max_p = nthrs;
+               return;
+       }
+
+       /*
+        * NB: we will add some common at here for estimating, for example:
+        * add a new member ptlrpc_service_thr_conf::tc_factor, and estimate
+        * threads number based on:
+        *     (online_cpus * conf::tc_factor) + conf::tc_nthrs_base.
+        *
+        * So we can remove code block like estimation in ost_setup, also,
+        * we might estimate MDS threads number as well instead of using
+        * absolute number, and have more threads on fat servers to improve
+        * availability of service.
+        *
+        * Also, we will need to validate threads number at here for
+        * CPT affinity service (CPU ParTiion) in the future.
+        * A service can have percpt thread-pool instead of a global thread
+        * pool for each service, which means user might not always get the
+        * threads number they want even they set it in conf::tc_nthrs_user,
+        * because we need to adjust threads number for each CPT, instead of
+        * just use (conf::tc_nthrs_user / NCPTS), to make sure each pool
+        * will be healthy.
+        */
+       *max_p = tc->tc_nthrs_max;
+       *min_p = nthrs_min;
+#else /* __KERNEL__ */
+       *max_p = *min_p = 1; /* whatever */
+#endif
+}
+
 /**
  * Initialize service on a given portal.
  * This includes starting serving threads , allocating and posting rqbds and
@@ -489,8 +536,10 @@ ptlrpc_register_service(struct ptlrpc_service_conf *conf,
        service->srv_req_portal         = conf->psc_buf.bc_req_portal;
        service->srv_request_seq        = 1; /* valid seq #s start at 1 */
        service->srv_request_max_cull_seq = 0;
-       service->srv_threads_min        = conf->psc_thr.tc_nthrs_min;
-       service->srv_threads_max        = conf->psc_thr.tc_nthrs_max;
+
+       ptlrpc_server_nthreads_check(conf, &service->srv_threads_min,
+                                    &service->srv_threads_max);
+
        service->srv_thread_name        = conf->psc_thr.tc_thr_name;
        service->srv_ctx_tags           = conf->psc_thr.tc_ctx_tags;
        service->srv_cpu_affinity       = !!conf->psc_thr.tc_cpu_affinity;