From e09b41010ba33a20a87472ee821fa407a5b8da36 Mon Sep 17 00:00:00 2001 From: José Pekkarinen Date: Mon, 11 Apr 2016 10:41:07 +0300 Subject: These changes are the raw update to linux-4.4.6-rt14. Kernel sources are taken from kernel.org, and rt patch from the rt wiki download page. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen --- kernel/net/rds/ib_recv.c | 198 +++++++++++++++++++++++------------------------ 1 file changed, 95 insertions(+), 103 deletions(-) (limited to 'kernel/net/rds/ib_recv.c') diff --git a/kernel/net/rds/ib_recv.c b/kernel/net/rds/ib_recv.c index 1b981a4e4..977fb8606 100644 --- a/kernel/net/rds/ib_recv.c +++ b/kernel/net/rds/ib_recv.c @@ -62,12 +62,12 @@ void rds_ib_recv_init_ring(struct rds_ib_connection *ic) sge = &recv->r_sge[0]; sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header)); sge->length = sizeof(struct rds_header); - sge->lkey = ic->i_mr->lkey; + sge->lkey = ic->i_pd->local_dma_lkey; sge = &recv->r_sge[1]; sge->addr = 0; sge->length = RDS_FRAG_SIZE; - sge->lkey = ic->i_mr->lkey; + sge->lkey = ic->i_pd->local_dma_lkey; } } @@ -297,7 +297,7 @@ static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic } static int rds_ib_recv_refill_one(struct rds_connection *conn, - struct rds_ib_recv_work *recv, int prefill) + struct rds_ib_recv_work *recv, gfp_t gfp) { struct rds_ib_connection *ic = conn->c_transport_data; struct ib_sge *sge; @@ -305,7 +305,7 @@ static int rds_ib_recv_refill_one(struct rds_connection *conn, gfp_t slab_mask = GFP_NOWAIT; gfp_t page_mask = GFP_NOWAIT; - if (prefill) { + if (gfp & __GFP_DIRECT_RECLAIM) { slab_mask = GFP_KERNEL; page_mask = GFP_HIGHUSER; } @@ -347,6 +347,24 @@ out: return ret; } +static int acquire_refill(struct rds_connection *conn) +{ + return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0; +} + +static void release_refill(struct rds_connection *conn) +{ + clear_bit(RDS_RECV_REFILL, &conn->c_flags); + + /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a + * hot path and finding waiters is very rare. We don't want to walk + * the system-wide hashed waitqueue buckets in the fast path only to + * almost never find waiters. + */ + if (waitqueue_active(&conn->c_waitq)) + wake_up_all(&conn->c_waitq); +} + /* * This tries to allocate and post unused work requests after making sure that * they have all the allocations they need to queue received fragments into @@ -354,15 +372,23 @@ out: * * -1 is returned if posting fails due to temporary resource exhaustion. */ -void rds_ib_recv_refill(struct rds_connection *conn, int prefill) +void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp) { struct rds_ib_connection *ic = conn->c_transport_data; struct rds_ib_recv_work *recv; struct ib_recv_wr *failed_wr; unsigned int posted = 0; int ret = 0; + bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM); u32 pos; + /* the goal here is to just make sure that someone, somewhere + * is posting buffers. If we can't get the refill lock, + * let them do their thing + */ + if (!acquire_refill(conn)) + return; + while ((prefill || rds_conn_up(conn)) && rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) { if (pos >= ic->i_recv_ring.w_nr) { @@ -372,7 +398,7 @@ void rds_ib_recv_refill(struct rds_connection *conn, int prefill) } recv = &ic->i_recvs[pos]; - ret = rds_ib_recv_refill_one(conn, recv, prefill); + ret = rds_ib_recv_refill_one(conn, recv, gfp); if (ret) { break; } @@ -402,6 +428,24 @@ void rds_ib_recv_refill(struct rds_connection *conn, int prefill) if (ret) rds_ib_ring_unalloc(&ic->i_recv_ring, 1); + + release_refill(conn); + + /* if we're called from the softirq handler, we'll be GFP_NOWAIT. + * in this case the ring being low is going to lead to more interrupts + * and we can safely let the softirq code take care of it unless the + * ring is completely empty. + * + * if we're called from krdsd, we'll be GFP_KERNEL. In this case + * we might have raced with the softirq code while we had the refill + * lock held. Use rds_ib_ring_low() instead of ring_empty to decide + * if we should requeue. + */ + if (rds_conn_up(conn) && + ((can_wait && rds_ib_ring_low(&ic->i_recv_ring)) || + rds_ib_ring_empty(&ic->i_recv_ring))) { + queue_delayed_work(rds_wq, &conn->c_recv_w, 1); + } } /* @@ -520,7 +564,7 @@ void rds_ib_recv_init_ack(struct rds_ib_connection *ic) sge->addr = ic->i_ack_dma; sge->length = sizeof(struct rds_header); - sge->lkey = ic->i_mr->lkey; + sge->lkey = ic->i_pd->local_dma_lkey; wr->sg_list = sge; wr->num_sge = 1; @@ -552,8 +596,7 @@ void rds_ib_recv_init_ack(struct rds_ib_connection *ic) * wr_id and avoids working with the ring in that case. */ #ifndef KERNEL_HAS_ATOMIC64 -static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, - int ack_required) +void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required) { unsigned long flags; @@ -578,8 +621,7 @@ static u64 rds_ib_get_ack(struct rds_ib_connection *ic) return seq; } #else -static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, - int ack_required) +void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required) { atomic64_set(&ic->i_ack_next, seq); if (ack_required) { @@ -786,20 +828,6 @@ static void rds_ib_cong_recv(struct rds_connection *conn, rds_cong_map_updated(map, uncongested); } -/* - * Rings are posted with all the allocations they'll need to queue the - * incoming message to the receiving socket so this can't fail. - * All fragments start with a header, so we can make sure we're not receiving - * garbage, and we can tell a small 8 byte fragment from an ACK frame. - */ -struct rds_ib_ack_state { - u64 ack_next; - u64 ack_recv; - unsigned int ack_required:1; - unsigned int ack_next_valid:1; - unsigned int ack_recv_valid:1; -}; - static void rds_ib_process_recv(struct rds_connection *conn, struct rds_ib_recv_work *recv, u32 data_len, struct rds_ib_ack_state *state) @@ -925,89 +953,50 @@ static void rds_ib_process_recv(struct rds_connection *conn, } } -/* - * Plucking the oldest entry from the ring can be done concurrently with - * the thread refilling the ring. Each ring operation is protected by - * spinlocks and the transient state of refilling doesn't change the - * recording of which entry is oldest. - * - * This relies on IB only calling one cq comp_handler for each cq so that - * there will only be one caller of rds_recv_incoming() per RDS connection. - */ -void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context) -{ - struct rds_connection *conn = context; - struct rds_ib_connection *ic = conn->c_transport_data; - - rdsdebug("conn %p cq %p\n", conn, cq); - - rds_ib_stats_inc(s_ib_rx_cq_call); - - tasklet_schedule(&ic->i_recv_tasklet); -} - -static inline void rds_poll_cq(struct rds_ib_connection *ic, - struct rds_ib_ack_state *state) +void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic, + struct ib_wc *wc, + struct rds_ib_ack_state *state) { struct rds_connection *conn = ic->conn; - struct ib_wc wc; struct rds_ib_recv_work *recv; - while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) { - rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n", - (unsigned long long)wc.wr_id, wc.status, - rds_ib_wc_status_str(wc.status), wc.byte_len, - be32_to_cpu(wc.ex.imm_data)); - rds_ib_stats_inc(s_ib_rx_cq_event); - - recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)]; + rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n", + (unsigned long long)wc->wr_id, wc->status, + ib_wc_status_msg(wc->status), wc->byte_len, + be32_to_cpu(wc->ex.imm_data)); - ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE); - - /* - * Also process recvs in connecting state because it is possible - * to get a recv completion _before_ the rdmacm ESTABLISHED - * event is processed. - */ - if (wc.status == IB_WC_SUCCESS) { - rds_ib_process_recv(conn, recv, wc.byte_len, state); - } else { - /* We expect errors as the qp is drained during shutdown */ - if (rds_conn_up(conn) || rds_conn_connecting(conn)) - rds_ib_conn_error(conn, "recv completion on %pI4 had " - "status %u (%s), disconnecting and " - "reconnecting\n", &conn->c_faddr, - wc.status, - rds_ib_wc_status_str(wc.status)); - } + rds_ib_stats_inc(s_ib_rx_cq_event); + recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)]; + ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, + DMA_FROM_DEVICE); - /* - * It's very important that we only free this ring entry if we've truly - * freed the resources allocated to the entry. The refilling path can - * leak if we don't. - */ - rds_ib_ring_free(&ic->i_recv_ring, 1); + /* Also process recvs in connecting state because it is possible + * to get a recv completion _before_ the rdmacm ESTABLISHED + * event is processed. + */ + if (wc->status == IB_WC_SUCCESS) { + rds_ib_process_recv(conn, recv, wc->byte_len, state); + } else { + /* We expect errors as the qp is drained during shutdown */ + if (rds_conn_up(conn) || rds_conn_connecting(conn)) + rds_ib_conn_error(conn, "recv completion on %pI4 had status %u (%s), disconnecting and reconnecting\n", + &conn->c_faddr, + wc->status, + ib_wc_status_msg(wc->status)); } -} - -void rds_ib_recv_tasklet_fn(unsigned long data) -{ - struct rds_ib_connection *ic = (struct rds_ib_connection *) data; - struct rds_connection *conn = ic->conn; - struct rds_ib_ack_state state = { 0, }; - - rds_poll_cq(ic, &state); - ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED); - rds_poll_cq(ic, &state); - if (state.ack_next_valid) - rds_ib_set_ack(ic, state.ack_next, state.ack_required); - if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) { - rds_send_drop_acked(conn, state.ack_recv, NULL); - ic->i_ack_recv = state.ack_recv; + /* rds_ib_process_recv() doesn't always consume the frag, and + * we might not have called it at all if the wc didn't indicate + * success. We already unmapped the frag's pages, though, and + * the following rds_ib_ring_free() call tells the refill path + * that it will not find an allocated frag here. Make sure we + * keep that promise by freeing a frag that's still on the ring. + */ + if (recv->r_frag) { + rds_ib_frag_free(ic, recv->r_frag); + recv->r_frag = NULL; } - if (rds_conn_up(conn)) - rds_ib_attempt_ack(ic); + rds_ib_ring_free(&ic->i_recv_ring, 1); /* If we ever end up with a really empty receive ring, we're * in deep trouble, as the sender will definitely see RNR @@ -1016,7 +1005,7 @@ void rds_ib_recv_tasklet_fn(unsigned long data) rds_ib_stats_inc(s_ib_rx_ring_empty); if (rds_ib_ring_low(&ic->i_recv_ring)) - rds_ib_recv_refill(conn, 0); + rds_ib_recv_refill(conn, 0, GFP_NOWAIT); } int rds_ib_recv(struct rds_connection *conn) @@ -1025,8 +1014,10 @@ int rds_ib_recv(struct rds_connection *conn) int ret = 0; rdsdebug("conn %p\n", conn); - if (rds_conn_up(conn)) + if (rds_conn_up(conn)) { rds_ib_attempt_ack(ic); + rds_ib_recv_refill(conn, 0, GFP_KERNEL); + } return ret; } @@ -1049,9 +1040,10 @@ int rds_ib_recv_init(void) rds_ib_frag_slab = kmem_cache_create("rds_ib_frag", sizeof(struct rds_page_frag), 0, SLAB_HWCACHE_ALIGN, NULL); - if (!rds_ib_frag_slab) + if (!rds_ib_frag_slab) { kmem_cache_destroy(rds_ib_incoming_slab); - else + rds_ib_incoming_slab = NULL; + } else ret = 0; out: return ret; -- cgit 1.2.3-korg