From 73e141f977163d93e60c30a177a99c44ecf72fe2 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Mon, 13 Jan 2014 15:33:27 -0800 Subject: [PATCH] ofproto-dpif-upcall: Avoid unnecessarily installing datapath flows. handle_upcalls() always installed a flow for every packet, as long as the datapath didn't already have too many flows, but there are cases where we don't want to do this: - If we get multiple packets in a single microflow all in one batch (perhaps due to GSO breaking up a large TCP packet for sending to userspace, or for another reason), then we only need to install the datapath flow once. - For a slow-pathed flow received via a slow-path action in the kernel, we know that the kernel flow is already there (because otherwise it would have been received as "no match" instead of an action), so there is no benefit to reinstalling it. Noticed because a CFM slow-pathed flow was getting reinstalled every time a CFM packet was received. Reported-by: Guolin Yang Signed-off-by: Ben Pfaff --- ofproto/ofproto-dpif-upcall.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c index dd24f5cb1..1e0c12ce4 100644 --- a/ofproto/ofproto-dpif-upcall.c +++ b/ofproto/ofproto-dpif-upcall.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc. +/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -208,6 +208,8 @@ struct flow_miss { struct odputil_keybuf mask_buf; struct xlate_out xout; + + bool put; }; static void upcall_destroy(struct upcall *); @@ -971,6 +973,7 @@ handle_upcalls(struct handler *handler, struct list *upcalls) miss->stats.used = time_msec(); miss->stats.tcp_flags = 0; miss->odp_in_port = odp_in_port; + miss->put = false; n_misses++; } else { @@ -1107,10 +1110,22 @@ handle_upcalls(struct handler *handler, struct list *upcalls) miss->flow.vlan_tci = 0; } - if (may_put) { + /* Do not install a flow into the datapath if: + * + * - The datapath already has too many flows. + * + * - An earlier iteration of this loop already put the same flow. + * + * - We received this packet via some flow installed in the kernel + * already. */ + if (may_put + && !miss->put + && upcall->dpif_upcall.type == DPIF_UC_MISS) { struct ofpbuf mask; bool megaflow; + miss->put = true; + atomic_read(&enable_megaflows, &megaflow); ofpbuf_use_stack(&mask, &miss->mask_buf, sizeof miss->mask_buf); if (megaflow) { -- 2.43.0