From fa55c6a4b41cd4fd240debe719b205056b04a0bf Mon Sep 17 00:00:00 2001 From: Liang Zhen Date: Sun, 1 Feb 2015 21:52:00 -0500 Subject: [PATCH] staging/lustre/ptlrpc: avoid list scan in ptlrpcd_check ptlrpcd_check() always scan all requests on ptlrpc_request_set and try to finish completed requests, this is low efficiency. Even worse, l_wait_event() always checks condition for twice before sleeping and one more time after waking up, which means it will call ptlrpcd_check() for three times in each loop. This patch will move completed requests at the head of list in ptlrpc_check_set(), with this change ptlrpcd_check doesn't need to scan all requests anymore. Signed-off-by: Liang Zhen Reviewed-on: http://review.whamcloud.com/11513 Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5548 Reviewed-by: Bobi Jam Reviewed-by: Andreas Dilger Reviewed-by: Johann Lombardi Signed-off-by: Oleg Drokin Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lustre/ptlrpc/client.c | 12 +++++++++- .../staging/lustre/lustre/ptlrpc/ptlrpcd.c | 23 ++++++++----------- 2 files changed, 20 insertions(+), 15 deletions(-) diff --git a/drivers/staging/lustre/lustre/ptlrpc/client.c b/drivers/staging/lustre/lustre/ptlrpc/client.c index dc9e406f3212..8c1ec830712f 100644 --- a/drivers/staging/lustre/lustre/ptlrpc/client.c +++ b/drivers/staging/lustre/lustre/ptlrpc/client.c @@ -1497,11 +1497,13 @@ static inline int ptlrpc_set_producer(struct ptlrpc_request_set *set) int ptlrpc_check_set(const struct lu_env *env, struct ptlrpc_request_set *set) { struct list_head *tmp, *next; + struct list_head comp_reqs; int force_timer_recalc = 0; if (atomic_read(&set->set_remaining) == 0) return 1; + INIT_LIST_HEAD(&comp_reqs); list_for_each_safe(tmp, next, &set->set_requests) { struct ptlrpc_request *req = list_entry(tmp, struct ptlrpc_request, @@ -1576,8 +1578,10 @@ int ptlrpc_check_set(const struct lu_env *env, struct ptlrpc_request_set *set) ptlrpc_rqphase_move(req, req->rq_next_phase); } - if (req->rq_phase == RQ_PHASE_COMPLETE) + if (req->rq_phase == RQ_PHASE_COMPLETE) { + list_move_tail(&req->rq_set_chain, &comp_reqs); continue; + } if (req->rq_phase == RQ_PHASE_INTERPRET) goto interpret; @@ -1860,9 +1864,15 @@ interpret: if (req->rq_status != 0) set->set_rc = req->rq_status; ptlrpc_req_finished(req); + } else { + list_move_tail(&req->rq_set_chain, &comp_reqs); } } + /* move completed request at the head of list so it's easier for + * caller to find them */ + list_splice(&comp_reqs, &set->set_requests); + /* If we hit an error, we want to recover promptly. */ return atomic_read(&set->set_remaining) == 0 || force_timer_recalc; } diff --git a/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c b/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c index cbcc541cac43..4621b71fe0b6 100644 --- a/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c +++ b/drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c @@ -306,21 +306,16 @@ static int ptlrpcd_check(struct lu_env *env, struct ptlrpcd_ctl *pc) if (atomic_read(&set->set_remaining)) rc |= ptlrpc_check_set(env, set); - if (!list_empty(&set->set_requests)) { - /* - * XXX: our set never completes, so we prune the completed - * reqs after each iteration. boy could this be smarter. - */ - list_for_each_safe(pos, tmp, &set->set_requests) { - req = list_entry(pos, struct ptlrpc_request, - rq_set_chain); - if (req->rq_phase != RQ_PHASE_COMPLETE) - continue; + /* NB: ptlrpc_check_set has already moved completed request at the + * head of seq::set_requests */ + list_for_each_safe(pos, tmp, &set->set_requests) { + req = list_entry(pos, struct ptlrpc_request, rq_set_chain); + if (req->rq_phase != RQ_PHASE_COMPLETE) + break; - list_del_init(&req->rq_set_chain); - req->rq_set = NULL; - ptlrpc_req_finished(req); - } + list_del_init(&req->rq_set_chain); + req->rq_set = NULL; + ptlrpc_req_finished(req); } if (rc == 0) { -- 2.20.1