From: Liang Zhen <liang.zhen@xxxxxxxxx> 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: Liang Zhen <liang.zhen@xxxxxxxxx> Signed-off-by: Doug Oucharek <doug.s.oucharek@xxxxxxxxx> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7099 Reviewed-on: http://review.whamcloud.com/20322 Reviewed-by: Amir Shehata <amir.shehata@xxxxxxxxx> Reviewed-by: Dmitry Eremin <dmitry.eremin@xxxxxxxxx> Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx> Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx> --- .../staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c | 46 ++++++++------------ 1 files changed, 18 insertions(+), 28 deletions(-) diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c index 6cd78ea..6d1b14a 100644 --- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c +++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c @@ -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); } } -- 1.7.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
