Author: mav
Date: Fri Dec 20 17:39:07 2013
New Revision: 259659
URL: http://svnweb.freebsd.org/changeset/base/259659
Log:
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.
Modified:
head/sys/nfs/nfs_fha.c
head/sys/rpc/svc.c
head/sys/rpc/svc.h
Modified: head/sys/nfs/nfs_fha.c
==============================================================================
--- head/sys/nfs/nfs_fha.c Fri Dec 20 16:50:52 2013 (r259658)
+++ head/sys/nfs/nfs_fha.c Fri Dec 20 17:39:07 2013 (r259659)
@@ -289,19 +289,6 @@ fha_hash_entry_add_op(struct fha_hash_en
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_
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, struc
if (req->rq_vers != 2 && req->rq_vers != 3)
return (this_thread);
- pool = req->rq_xprt->xp_pool;
fha_extract_info(req, &i, cb);
/*
Modified: head/sys/rpc/svc.c
==============================================================================
--- head/sys/rpc/svc.c Fri Dec 20 16:50:52 2013 (r259658)
+++ head/sys/rpc/svc.c Fri Dec 20 17:39:07 2013 (r259659)
@@ -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 i
* 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 i
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 i
* 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 i
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);
Modified: head/sys/rpc/svc.h
==============================================================================
--- head/sys/rpc/svc.h Fri Dec 20 16:50:52 2013 (r259658)
+++ head/sys/rpc/svc.h Fri Dec 20 17:39:07 2013 (r259659)
@@ -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 */
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