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Commit ba530142 authored by Liang Zhen's avatar Liang Zhen Committed by Greg Kroah-Hartman
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staging: lustre: lnet: lock improvement for ko2iblnd 



kiblnd_check_sends() takes conn::ibc_lock at the begin and release
this lock at the end, this is inefficient because most use-case
needs to explicitly release ibc_lock before caling this function.

This patches changes it to kiblnd_check_sends_locked() and avoid
unnecessary lock dances.

Signed-off-by: default avatarLiang Zhen <liang.zhen@intel.com>
Signed-off-by: default avatarDoug Oucharek <doug.s.oucharek@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7099
Reviewed-on: http://review.whamcloud.com/20322


Reviewed-by: default avatarAmir Shehata <amir.shehata@intel.com>
Reviewed-by: default avatarDmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: default avatarOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: default avatarJames Simmons <jsimmons@infradead.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d04c0943

drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c

+18 −28
Original line number Diff line number Diff line
@@ -38,7 +38,6 @@ 


static void kiblnd_peer_alive(struct kib_peer *peer);

static void kiblnd_peer_connect_failed(struct kib_peer *peer, int active, int error);

static void kiblnd_check_sends(struct kib_conn *conn);

static void kiblnd_init_tx_msg(lnet_ni_t *ni, struct kib_tx *tx,

				int type, int body_nob);

static int kiblnd_init_rdma(struct kib_conn *conn, struct kib_tx *tx, int type,
@@ -46,6 +45,7 @@ static int kiblnd_init_rdma(struct kib_conn *conn, struct kib_tx *tx, int type, 
static void kiblnd_queue_tx_locked(struct kib_tx *tx, struct kib_conn *conn);

static void kiblnd_queue_tx(struct kib_tx *tx, struct kib_conn *conn);

static void kiblnd_unmap_tx(lnet_ni_t *ni, struct kib_tx *tx);

static void kiblnd_check_sends_locked(struct kib_conn *conn);



static void

kiblnd_tx_done(lnet_ni_t *ni, struct kib_tx *tx)
@@ -211,9 +211,9 @@ kiblnd_post_rx(struct kib_rx *rx, int credit) 
		conn->ibc_outstanding_credits++;

	else

		conn->ibc_reserved_credits++;

	kiblnd_check_sends_locked(conn);

	spin_unlock(&conn->ibc_lock);



	kiblnd_check_sends(conn);

out:

	kiblnd_conn_decref(conn);

	return rc;
@@ -344,8 +344,8 @@ kiblnd_handle_rx(struct kib_rx *rx) 
		    !IBLND_OOB_CAPABLE(conn->ibc_version)) /* v1 only */

			conn->ibc_outstanding_credits++;



		kiblnd_check_sends_locked(conn);

		spin_unlock(&conn->ibc_lock);

		kiblnd_check_sends(conn);

	}



	switch (msg->ibm_type) {
@@ -800,7 +800,7 @@ kiblnd_post_tx_locked(struct kib_conn *conn, struct kib_tx *tx, int credit) 
	      conn->ibc_noops_posted == IBLND_OOB_MSGS(ver)))) {

		/*

		 * OK to drop when posted enough NOOPs, since

		 * kiblnd_check_sends will queue NOOP again when

		 * kiblnd_check_sends_locked will queue NOOP again when

		 * posted NOOPs complete

		 */

		spin_unlock(&conn->ibc_lock);
@@ -905,7 +905,7 @@ kiblnd_post_tx_locked(struct kib_conn *conn, struct kib_tx *tx, int credit) 
}



static void

kiblnd_check_sends(struct kib_conn *conn)

kiblnd_check_sends_locked(struct kib_conn *conn)

{

	int ver = conn->ibc_version;

	lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
@@ -918,8 +918,6 @@ kiblnd_check_sends(struct kib_conn *conn) 
		return;

	}



	spin_lock(&conn->ibc_lock);



	LASSERT(conn->ibc_nsends_posted <= kiblnd_concurrent_sends(ver, ni));

	LASSERT(!IBLND_OOB_CAPABLE(ver) ||

		conn->ibc_noops_posted <= IBLND_OOB_MSGS(ver));
@@ -969,8 +967,6 @@ kiblnd_check_sends(struct kib_conn *conn) 
		if (kiblnd_post_tx_locked(conn, tx, credit))

			break;

	}



	spin_unlock(&conn->ibc_lock);

}



static void
@@ -1016,16 +1012,11 @@ kiblnd_tx_complete(struct kib_tx *tx, int status) 
	if (idle)

		list_del(&tx->tx_list);



	kiblnd_conn_addref(conn);	       /* 1 ref for me.... */



	kiblnd_check_sends_locked(conn);

	spin_unlock(&conn->ibc_lock);



	if (idle)

		kiblnd_tx_done(conn->ibc_peer->ibp_ni, tx);



	kiblnd_check_sends(conn);



	kiblnd_conn_decref(conn);	       /* ...until here */

}



static void
@@ -1204,9 +1195,8 @@ kiblnd_queue_tx(struct kib_tx *tx, struct kib_conn *conn) 
{

	spin_lock(&conn->ibc_lock);

	kiblnd_queue_tx_locked(tx, conn);

	kiblnd_check_sends_locked(conn);

	spin_unlock(&conn->ibc_lock);



	kiblnd_check_sends(conn);

}



static int kiblnd_resolve_addr(struct rdma_cm_id *cmid,
@@ -2183,14 +2173,11 @@ kiblnd_connreq_done(struct kib_conn *conn, int status) 
		return;

	}



	/**

	 * refcount taken by cmid is not reliable after I released the glock

	 * because this connection is visible to other threads now, another

	 * thread can find and close this connection right after I released

	 * the glock, if kiblnd_cm_callback for RDMA_CM_EVENT_DISCONNECTED is

	 * called, it can release the connection refcount taken by cmid.

	 * It means the connection could be destroyed before I finish my

	 * operations on it.

	/*

	 * +1 ref for myself, this connection is visible to other threads

	 * now, refcount of peer:ibp_conns can be released by connection

	 * close from either a different thread, or the calling of

	 * kiblnd_check_sends_locked() below. See bz21911 for details.

	 */

	kiblnd_conn_addref(conn);

	write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
@@ -2202,10 +2189,9 @@ kiblnd_connreq_done(struct kib_conn *conn, int status) 


		kiblnd_queue_tx_locked(tx, conn);

	}

	kiblnd_check_sends_locked(conn);

	spin_unlock(&conn->ibc_lock);



	kiblnd_check_sends(conn);



	/* schedule blocked rxs */

	kiblnd_handle_early_rxs(conn);
@@ -3233,7 +3219,11 @@ kiblnd_check_conns(int idx) 
	 */

	list_for_each_entry_safe(conn, temp, &checksends, ibc_connd_list) {

		list_del(&conn->ibc_connd_list);

		kiblnd_check_sends(conn);



		spin_lock(&conn->ibc_lock);

		kiblnd_check_sends_locked(conn);

		spin_unlock(&conn->ibc_lock);



		kiblnd_conn_decref(conn);

	}

}