From ba981145d6dcc5a8aa74ab993084e2dc16d94224 Mon Sep 17 00:00:00 2001 From: Alexander Motin Date: Fri, 20 Dec 2013 17:39:07 +0000 Subject: [PATCH] Remove several linear list traversals per request from RPC server code. Do not insert active ports into pool->sp_active list if they are success- fully assigned to some thread. This makes that list include only ports that really require attention, and so traversal can be reduced to simple taking the first one. Remove idle thread from pool->sp_idlethreads list when assigning some work (port of requests) to it. That again makes possible to replace list traversals with simple taking the first element. --- sys/nfs/nfs_fha.c | 17 +--------- sys/rpc/svc.c | 86 +++++++++++++++++++++++++---------------------- sys/rpc/svc.h | 1 + 3 files changed, 47 insertions(+), 57 deletions(-) diff --git a/sys/nfs/nfs_fha.c b/sys/nfs/nfs_fha.c index dd9ee276889b..229080471171 100644 --- a/sys/nfs/nfs_fha.c +++ b/sys/nfs/nfs_fha.c @@ -289,19 +289,6 @@ fha_hash_entry_add_op(struct fha_hash_entry *fhe, int locktype, int count) fhe->num_rw += count; } -static SVCTHREAD * -get_idle_thread(SVCPOOL *pool) -{ - SVCTHREAD *st; - - LIST_FOREACH(st, &pool->sp_idlethreads, st_ilink) { - if (st->st_xprt == NULL && STAILQ_EMPTY(&st->st_reqs)) - return (st); - } - return (NULL); -} - - /* * Get the service thread currently associated with the fhe that is * appropriate to handle this operation. @@ -386,7 +373,7 @@ fha_hash_entry_choose_thread(struct fha_params *softc, ITRACE_CURPROC(ITRACE_NFS, ITRACE_INFO, "fha: %p(%d)t", thread, thread->st_reqcount); #endif - } else if ((thread = get_idle_thread(pool))) { + } else if ((thread = LIST_FIRST(&pool->sp_idlethreads))) { #if 0 ITRACE_CURPROC(ITRACE_NFS, ITRACE_INFO, "fha: %p(%d)i", thread, thread->st_reqcount); @@ -418,7 +405,6 @@ SVCTHREAD * fha_assign(SVCTHREAD *this_thread, struct svc_req *req, struct fha_params *softc) { - SVCPOOL *pool; SVCTHREAD *thread; struct fha_info i; struct fha_hash_entry *fhe; @@ -439,7 +425,6 @@ fha_assign(SVCTHREAD *this_thread, struct svc_req *req, if (req->rq_vers != 2 && req->rq_vers != 3) return (this_thread); - pool = req->rq_xprt->xp_pool; fha_extract_info(req, &i, cb); /* diff --git a/sys/rpc/svc.c b/sys/rpc/svc.c index 5b480863669e..bf23d4aaeb31 100644 --- a/sys/rpc/svc.c +++ b/sys/rpc/svc.c @@ -293,12 +293,10 @@ xprt_unregister_locked(SVCXPRT *xprt) { SVCPOOL *pool = xprt->xp_pool; + mtx_assert(&xprt->xp_mlock, MA_OWNED); KASSERT(xprt->xp_registered == TRUE, ("xprt_unregister_locked: not registered")); - if (xprt->xp_active) { - TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink); - xprt->xp_active = FALSE; - } + xprt_inactive_locked(xprt); TAILQ_REMOVE(&pool->sp_xlist, xprt, xp_link); xprt->xp_registered = FALSE; } @@ -320,25 +318,25 @@ xprt_unregister(SVCXPRT *xprt) SVC_RELEASE(xprt); } -static void +/* + * Attempt to assign a service thread to this transport. + */ +static int xprt_assignthread(SVCXPRT *xprt) { SVCPOOL *pool = xprt->xp_pool; SVCTHREAD *st; - /* - * Attempt to assign a service thread to this - * transport. - */ - LIST_FOREACH(st, &pool->sp_idlethreads, st_ilink) { - if (st->st_xprt == NULL && STAILQ_EMPTY(&st->st_reqs)) - break; - } + mtx_assert(&xprt->xp_mlock, MA_OWNED); + st = LIST_FIRST(&pool->sp_idlethreads); if (st) { + LIST_REMOVE(st, st_ilink); + st->st_idle = FALSE; SVC_ACQUIRE(xprt); xprt->xp_thread = st; st->st_xprt = xprt; cv_signal(&st->st_cond); + return (TRUE); } else { /* * See if we can create a new thread. The @@ -354,6 +352,7 @@ xprt_assignthread(SVCXPRT *xprt) pool->sp_state = SVCPOOL_THREADWANTED; } } + return (FALSE); } void @@ -372,9 +371,12 @@ xprt_active(SVCXPRT *xprt) } if (!xprt->xp_active) { - TAILQ_INSERT_TAIL(&pool->sp_active, xprt, xp_alink); xprt->xp_active = TRUE; - xprt_assignthread(xprt); + if (xprt->xp_thread == NULL) { + if (!xprt_assignthread(xprt)) + TAILQ_INSERT_TAIL(&pool->sp_active, xprt, + xp_alink); + } } mtx_unlock(&pool->sp_lock); @@ -385,8 +387,10 @@ xprt_inactive_locked(SVCXPRT *xprt) { SVCPOOL *pool = xprt->xp_pool; + mtx_assert(&xprt->xp_mlock, MA_OWNED); if (xprt->xp_active) { - TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink); + if (xprt->xp_thread == NULL) + TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink); xprt->xp_active = FALSE; } } @@ -948,10 +952,11 @@ svc_assign_waiting_sockets(SVCPOOL *pool) { SVCXPRT *xprt; - TAILQ_FOREACH(xprt, &pool->sp_active, xp_alink) { - if (!xprt->xp_thread) { - xprt_assignthread(xprt); - } + while ((xprt = TAILQ_FIRST(&pool->sp_active)) != NULL) { + if (xprt_assignthread(xprt)) + TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink); + else + break; } } @@ -1042,21 +1047,17 @@ svc_run_internal(SVCPOOL *pool, bool_t ismaster) * active transport which isn't being serviced * by a thread. */ - if (svc_request_space_available(pool)) { - TAILQ_FOREACH(xprt, &pool->sp_active, - xp_alink) { - if (!xprt->xp_thread) { - SVC_ACQUIRE(xprt); - xprt->xp_thread = st; - st->st_xprt = xprt; - break; - } - } - } - if (st->st_xprt) + if (svc_request_space_available(pool) && + (xprt = TAILQ_FIRST(&pool->sp_active)) != NULL) { + TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink); + SVC_ACQUIRE(xprt); + xprt->xp_thread = st; + st->st_xprt = xprt; continue; + } LIST_INSERT_HEAD(&pool->sp_idlethreads, st, st_ilink); + st->st_idle = TRUE; if (ismaster || (!ismaster && pool->sp_threadcount > pool->sp_minthreads)) error = cv_timedwait_sig(&st->st_cond, @@ -1064,7 +1065,10 @@ svc_run_internal(SVCPOOL *pool, bool_t ismaster) else error = cv_wait_sig(&st->st_cond, &pool->sp_lock); - LIST_REMOVE(st, st_ilink); + if (st->st_idle) { + LIST_REMOVE(st, st_ilink); + st->st_idle = FALSE; + } /* * Reduce worker thread count when idle. @@ -1132,11 +1136,12 @@ svc_run_internal(SVCPOOL *pool, bool_t ismaster) * execute the request * immediately. */ - if (stpref != st) { - cv_signal(&stpref->st_cond); - continue; - } else { + if (stpref == st) break; + if (stpref->st_idle) { + LIST_REMOVE(stpref, st_ilink); + stpref->st_idle = FALSE; + cv_signal(&stpref->st_cond); } } } while (stat == XPRT_MOREREQS @@ -1153,10 +1158,9 @@ svc_run_internal(SVCPOOL *pool, bool_t ismaster) xprt->xp_thread = NULL; st->st_xprt = NULL; if (xprt->xp_active) { - xprt_assignthread(xprt); - TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink); - TAILQ_INSERT_TAIL(&pool->sp_active, xprt, - xp_alink); + if (!xprt_assignthread(xprt)) + TAILQ_INSERT_TAIL(&pool->sp_active, + xprt, xp_alink); } mtx_unlock(&pool->sp_lock); SVC_RELEASE(xprt); diff --git a/sys/rpc/svc.h b/sys/rpc/svc.h index 28a3c5db678f..0b2884f3ef07 100644 --- a/sys/rpc/svc.h +++ b/sys/rpc/svc.h @@ -278,6 +278,7 @@ typedef struct __rpc_svcthread { SVCXPRT *st_xprt; /* transport we are processing */ struct svc_reqlist st_reqs; /* RPC requests to execute */ int st_reqcount; /* number of queued reqs */ + int st_idle; /* thread is on idle list */ struct cv st_cond; /* sleeping for work */ LIST_ENTRY(__rpc_svcthread) st_link; /* all threads list */ LIST_ENTRY(__rpc_svcthread) st_ilink; /* idle threads list */