Commit fa55c6a4 authored by Liang Zhen's avatar Liang Zhen Committed by Greg Kroah-Hartman
Browse files

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: default avatarLiang Zhen <liang.zhen@intel.com>
Reviewed-on: http://review.whamcloud.com/11513
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5548


Reviewed-by: default avatarBobi Jam <bobijam@gmail.com>
Reviewed-by: default avatarAndreas Dilger <andreas.dilger@intel.com>
Reviewed-by: default avatarJohann Lombardi <johann.lombardi@intel.com>
Signed-off-by: default avatarOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b47ea4bb

drivers/staging/lustre/lustre/ptlrpc/client.c

+11 −1
Original line number Diff line number Diff line
@@ -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;

}

drivers/staging/lustre/lustre/ptlrpc/ptlrpcd.c

+9 −14
Original line number Diff line number Diff line
@@ -306,22 +306,17 @@ 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.

		 */

	/* 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);

		req = list_entry(pos, struct ptlrpc_request, rq_set_chain);

		if (req->rq_phase != RQ_PHASE_COMPLETE)

				continue;

			break;



		list_del_init(&req->rq_set_chain);

		req->rq_set = NULL;

		ptlrpc_req_finished(req);

	}

	}



	if (rc == 0) {

		/*

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