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* net: dev_weight: TX/RX orthogonalityMatthias Tafelmeier2016-12-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Oftenly, introducing side effects on packet processing on the other half of the stack by adjusting one of TX/RX via sysctl is not desirable. There are cases of demand for asymmetric, orthogonal configurability. This holds true especially for nodes where RPS for RFS usage on top is configured and therefore use the 'old dev_weight'. This is quite a common base configuration setup nowadays, even with NICs of superior processing support (e.g. aRFS). A good example use case are nodes acting as noSQL data bases with a large number of tiny requests and rather fewer but large packets as responses. It's affordable to have large budget and rx dev_weights for the requests. But as a side effect having this large a number on TX processed in one run can overwhelm drivers. This patch therefore introduces an independent configurability via sysctl to userland. Signed-off-by: Matthias Tafelmeier <matthias.tafelmeier@gmx.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: gen_estimator: complete rewrite of rate estimatorsEric Dumazet2016-12-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1) Old code was hard to maintain, due to complex lock chains. (We probably will be able to remove some kfree_rcu() in callers) 2) Using a single timer to update all estimators does not scale. 3) Code was buggy on 32bit kernel (WRITE_ONCE() on 64bit quantity is not supposed to work well) In this rewrite : - I removed the RB tree that had to be scanned in gen_estimator_active(). qdisc dumps should be much faster. - Each estimator has its own timer. - Estimations are maintained in net_rate_estimator structure, instead of dirtying the qdisc. Minor, but part of the simplification. - Reading the estimator uses RCU and a seqcount to provide proper support for 32bit kernels. - We reduce memory need when estimators are not used, since we store a pointer, instead of the bytes/packets counters. - xt_rateest_mt() no longer has to grab a spinlock. (In the future, xt_rateest_tg() could be switched to per cpu counters) Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* sched: add and use qdisc_skb_head helpersFlorian Westphal2016-09-191-10/+11
| | | | | | | | | | | | | | | | | This change replaces sk_buff_head struct in Qdiscs with new qdisc_skb_head. Its similar to the skb_buff_head api, but does not use skb->prev pointers. Qdiscs will commonly enqueue at the tail of a list and dequeue at head. While skb_buff_head works fine for this, enqueue/dequeue needs to also adjust the prev pointer of next element. The ->prev pointer is not required for qdiscs so we can just leave it undefined and avoid one cacheline write access for en/dequeue. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* sched: remove qdisc arg from __qdisc_dequeue_headFlorian Westphal2016-09-191-1/+6
| | | | | | | | | | | | | Moves qdisc stat accouting to qdisc_dequeue_head. The only direct caller of the __qdisc_dequeue_head version open-codes this now. This allows us to later use __qdisc_dequeue_head as a replacement of __skb_dequeue() (which operates on sk_buff_head list). Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* sched: don't use skb queue helpersFlorian Westphal2016-09-191-1/+1
| | | | | | | | | | | | | A followup change will replace the sk_buff_head in the qdisc struct with a slightly different list. Use of the sk_buff_head helpers will thus cause compiler warnings. Open-code these accesses in an extra change to ease review. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2016-08-301-4/+5
|\ | | | | | | | | | | | | All three conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
| * qdisc: fix a module refcount leak in qdisc_create_dflt()Eric Dumazet2016-08-251-4/+5
| | | | | | | | | | | | | | | | | | | | | | Should qdisc_alloc() fail, we must release the module refcount we got right before. Fixes: 6da7c8fcbcbd ("qdisc: allow setting default queuing discipline") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net: sched: convert qdisc linked list to hashtableJiri Kosina2016-08-101-3/+5
|/ | | | | | | | | | | | | | | Convert the per-device linked list into a hashtable. The primary motivation for this change is that currently, we're not tracking all the qdiscs in hierarchy (e.g. excluding default qdiscs), as the lookup performed over the linked list by qdisc_match_from_root() is rather expensive. The ultimate goal is to get rid of hidden qdiscs completely, which will bring much more determinism in user experience. Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: generalize bulk dequeueEric Dumazet2016-06-251-10/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When qdisc bulk dequeue was added in linux-3.18 (commit 5772e9a3463b "qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE"), it was constrained to some specific qdiscs. With some extra care, we can extend this to all qdiscs, so that typical traffic shaping solutions can benefit from small batches (8 packets in this patch). For example, HTB is often used on some multi queue device. And bonding/team are multi queue devices... Idea is to bulk-dequeue packets mapping to the same transmit queue. This brings between 35 and 80 % performance increase in HTB setup under pressure on a bonding setup : 1) NUMA node contention : 610,000 pps -> 1,110,000 pps 2) No node contention : 1,380,000 pps -> 1,930,000 pps Now we should work to add batches on the enqueue() side ;) Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Florian Westphal <fw@strlen.de> Cc: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: drop packets after root qdisc lock is releasedEric Dumazet2016-06-251-4/+6
| | | | | | | | | | | | | | | | | | | | | | Qdisc performance suffers when packets are dropped at enqueue() time because drops (kfree_skb()) are done while qdisc lock is held, delaying a dequeue() draining the queue. Nominal throughput can be reduced by 50 % when this happens, at a time we would like the dequeue() to proceed as fast as possible. Even FQ is vulnerable to this problem, while one of FQ goals was to provide some flow isolation. This patch adds a 'struct sk_buff **to_free' parameter to all qdisc->enqueue(), and in qdisc_drop() helper. I measured a performance increase of up to 12 %, but this patch is a prereq so that future batches in enqueue() can fly. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: add the ability to defer skb freeingEric Dumazet2016-06-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | qdisc are changed under RTNL protection and often while blocking BH and root qdisc spinlock. When lots of skbs need to be dropped, we free them under these locks causing TX/RX freezes, and more generally latency spikes. This commit adds rtnl_kfree_skbs(), used to queue skbs for deferred freeing. Actual freeing happens right after RTNL is released, with appropriate scheduling points. rtnl_qdisc_drop() can also be used in place of disc_drop() when RTNL is held. qdisc_reset_queue() and __qdisc_reset_queue() get the new behavior, so standard qdiscs like pfifo, pfifo_fast... have their ->reset() method automatically handled. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2016-06-101-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: net/sched/act_police.c net/sched/sch_drr.c net/sched/sch_hfsc.c net/sched/sch_prio.c net/sched/sch_red.c net/sched/sch_tbf.c In net-next the drop methods of the packet schedulers got removed, so the bug fixes to them in 'net' are irrelevant. A packet action unload crash fix conflicts with the addition of the new firstuse timestamp. Signed-off-by: David S. Miller <davem@davemloft.net>
| * net_sched: keep backlog updated with qlenWANG Cong2016-06-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | For gso_skb we only update qlen, backlog should be updated too. Note, it is correct to just update these stats at one layer, because the gso_skb is cached there. Reported-by: Stas Nichiporovich <stasn77@gmail.com> Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too") Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net: sched: fix qdisc->running lockdep annotationsEric Dumazet2016-06-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | 1) qdisc_run_begin() is really using the equivalent of a trylock. Instead of using write_seqcount_begin(), use a combination of raw_write_seqcount_begin() and correct lockdep annotation. 2) sch_direct_xmit() should use regular spin_lock(root_lock) Fixes: f9eb8aea2a1e ("net_sched: transform qdisc running bit into a seqcount") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net_sched: transform qdisc running bit into a seqcountEric Dumazet2016-06-071-4/+10
|/ | | | | | | | | | | | | Instead of using a single bit (__QDISC___STATE_RUNNING) in sch->__state, use a seqcount. This adds lockdep support, but more importantly it will allow us to sample qdisc/class statistics without having to grab qdisc root lock. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: remove dev->trans_startFlorian Westphal2016-05-041-7/+3
| | | | | | | | | | | | | | | previous patches removed all direct accesses to dev->trans_start, so change the netif_trans_update helper to update trans_start of netdev queue 0 instead and then remove trans_start from struct net_device. AFAICS a lot of the netif_trans_update() invocations are now useless because they occur in ndo_start_xmit and driver doesn't set LLTX (i.e. stack already took care of the update). As I can't test any of them it seems better to just leave them alone. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* treewide: replace dev->trans_start update with helperFlorian Westphal2016-05-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace all trans_start updates with netif_trans_update helper. change was done via spatch: struct net_device *d; @@ - d->trans_start = jiffies + netif_trans_update(d) Compile tested only. Cc: user-mode-linux-devel@lists.sourceforge.net Cc: linux-xtensa@linux-xtensa.org Cc: linux1394-devel@lists.sourceforge.net Cc: linux-rdma@vger.kernel.org Cc: netdev@vger.kernel.org Cc: MPT-FusionLinux.pdl@broadcom.com Cc: linux-scsi@vger.kernel.org Cc: linux-can@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-omap@vger.kernel.org Cc: linux-hams@vger.kernel.org Cc: linux-usb@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: devel@driverdev.osuosl.org Cc: b.a.t.m.a.n@lists.open-mesh.org Cc: linux-bluetooth@vger.kernel.org Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Acked-by: Mugunthan V N <mugunthanvnm@ti.com> Acked-by: Antonio Quartulli <a@unstable.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: remove NETDEV_TX_LOCKED supportFlorian Westphal2016-04-261-32/+0
| | | | | | | | | No more users in the tree, remove NETDEV_TX_LOCKED support. Adds another hole in softnet_stats struct, but better than keeping the unused collision counter around. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: do not requeue a NULL skbLars Persson2016-04-141-1/+4
| | | | | | | | | | | | | | | A failure in validate_xmit_skb_list() triggered an unconditional call to dev_requeue_skb with skb=NULL. This slowly grows the queue discipline's qlen count until all traffic through the queue stops. We take the optimistic approach and continue running the queue after a failure since it is unknown if later packets also will fail in the validate path. Fixes: 55a93b3ea780 ("qdisc: validate skb without holding lock") Signed-off-by: Lars Persson <larper@axis.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: use pfifo_fast for non real queuesEric Dumazet2016-03-031-0/+1
| | | | | | | | | | | Some devices declare a high number of TX queues, then set a much lower real_num_tx_queues This cause setups using fq_codel, sfq or fq as the default qdisc to consume more memory than really needed. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: fix missing free per cpu on qstatsJohn Fastabend2016-01-061-1/+3
| | | | | | | | | | | When a qdisc is using per cpu stats (currently just the ingress qdisc) only the bstats are being freed. This also free's the qstats. Fixes: b0ab6f92752b9f9d8 ("net: sched: enable per cpu qstats") Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: fix qdisc_tree_decrease_qlen() racesEric Dumazet2015-12-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | qdisc_tree_decrease_qlen() suffers from two problems on multiqueue devices. One problem is that it updates sch->q.qlen and sch->qstats.drops on the mq/mqprio root qdisc, while it should not : Daniele reported underflows errors : [ 681.774821] PAX: sch->q.qlen: 0 n: 1 [ 681.774825] PAX: size overflow detected in function qdisc_tree_decrease_qlen net/sched/sch_api.c:769 cicus.693_49 min, count: 72, decl: qlen; num: 0; context: sk_buff_head; [ 681.774954] CPU: 2 PID: 19 Comm: ksoftirqd/2 Tainted: G O 4.2.6.201511282239-1-grsec #1 [ 681.774955] Hardware name: ASUSTeK COMPUTER INC. X302LJ/X302LJ, BIOS X302LJ.202 03/05/2015 [ 681.774956] ffffffffa9a04863 0000000000000000 0000000000000000 ffffffffa990ff7c [ 681.774959] ffffc90000d3bc38 ffffffffa95d2810 0000000000000007 ffffffffa991002b [ 681.774960] ffffc90000d3bc68 ffffffffa91a44f4 0000000000000001 0000000000000001 [ 681.774962] Call Trace: [ 681.774967] [<ffffffffa95d2810>] dump_stack+0x4c/0x7f [ 681.774970] [<ffffffffa91a44f4>] report_size_overflow+0x34/0x50 [ 681.774972] [<ffffffffa94d17e2>] qdisc_tree_decrease_qlen+0x152/0x160 [ 681.774976] [<ffffffffc02694b1>] fq_codel_dequeue+0x7b1/0x820 [sch_fq_codel] [ 681.774978] [<ffffffffc02680a0>] ? qdisc_peek_dequeued+0xa0/0xa0 [sch_fq_codel] [ 681.774980] [<ffffffffa94cd92d>] __qdisc_run+0x4d/0x1d0 [ 681.774983] [<ffffffffa949b2b2>] net_tx_action+0xc2/0x160 [ 681.774985] [<ffffffffa90664c1>] __do_softirq+0xf1/0x200 [ 681.774987] [<ffffffffa90665ee>] run_ksoftirqd+0x1e/0x30 [ 681.774989] [<ffffffffa90896b0>] smpboot_thread_fn+0x150/0x260 [ 681.774991] [<ffffffffa9089560>] ? sort_range+0x40/0x40 [ 681.774992] [<ffffffffa9085fe4>] kthread+0xe4/0x100 [ 681.774994] [<ffffffffa9085f00>] ? kthread_worker_fn+0x170/0x170 [ 681.774995] [<ffffffffa95d8d1e>] ret_from_fork+0x3e/0x70 mq/mqprio have their own ways to report qlen/drops by folding stats on all their queues, with appropriate locking. A second problem is that qdisc_tree_decrease_qlen() calls qdisc_lookup() without proper locking : concurrent qdisc updates could corrupt the list that qdisc_match_from_root() parses to find a qdisc given its handle. Fix first problem adding a TCQ_F_NOPARENT qdisc flag that qdisc_tree_decrease_qlen() can use to abort its tree traversal, as soon as it meets a mq/mqprio qdisc children. Second problem can be fixed by RCU protection. Qdisc are already freed after RCU grace period, so qdisc_list_add() and qdisc_list_del() simply have to use appropriate rcu list variants. A future patch will add a per struct netdev_queue list anchor, so that qdisc_tree_decrease_qlen() can have more efficient lookups. Reported-by: Daniele Fucini <dfucini@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Cong Wang <cwang@twopensource.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: simplify attach_one_default_qdisc()Phil Sutter2015-08-271-29/+12
| | | | | | | | | | | | Now that noqueue qdisc can be attached just like any other qdisc, no special treatment is necessary anymore when attaching it as default qdisc. This change has the added benefit that 'tc qdisc show' prints noqueue instead of nothing for devices defaulting to noqueue. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: register noqueue qdiscPhil Sutter2015-08-271-1/+11
| | | | | | | | This way users can attach noqueue just like any other qdisc using tc without having to mess with tx_queue_len first. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: ignore tx_queue_len when assigning default qdiscPhil Sutter2015-08-271-2/+1
| | | | | | | | | Since alloc_netdev_mqs() sets IFF_NO_QUEUE for drivers not initializing tx_queue_len, it is safe to assume that if tx_queue_len is zero, dev->priv flags always contains IFF_NO_QUEUE. Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sch_generic: react upon IFF_NO_QUEUE flagPhil Sutter2015-08-171-2/+4
| | | | | | | | Handle IFF_NO_QUEUE as alternative to tx_queue_len being zero. Signed-off-by: Phil Sutter <phil@nwl.cc> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: restore qdisc quota fairness limits after bulk dequeueJesper Dangaard Brouer2014-10-091-7/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Restore the quota fairness between qdisc's, that we broke with commit 5772e9a346 ("qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE"). Before that commit, the quota in __qdisc_run() were in packets as dequeue_skb() would only dequeue a single packet, that assumption broke with bulk dequeue. We choose not to account for the number of packets inside the TSO/GSO packets (accessable via "skb_gso_segs"). As the previous fairness also had this "defect". Thus, GSO/TSO packets counts as a single packet. Further more, we choose to slack on accuracy, by allowing a bulk dequeue try_bulk_dequeue_skb() to exceed the "packets" limit, only limited by the BQL bytelimit. This is done because BQL prefers to get its full budget for appropriate feedback from TX completion. In future, we might consider reworking this further and, if it allows, switch to a time-based model, as suggested by Eric. Right now, we only restore old semantics. Joint work with Eric, Hannes, Daniel and Jesper. Hannes wrote the first patch in cooperation with Daniel and Jesper. Eric rewrote the patch. Fixes: 5772e9a346 ("qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: better IFF_XMIT_DST_RELEASE supportEric Dumazet2014-10-071-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Testing xmit_more support with netperf and connected UDP sockets, I found strange dst refcount false sharing. Current handling of IFF_XMIT_DST_RELEASE is not optimal. Dropping dst in validate_xmit_skb() is certainly too late in case packet was queued by cpu X but dequeued by cpu Y The logical point to take care of drop/force is in __dev_queue_xmit() before even taking qdisc lock. As Julian Anastasov pointed out, need for skb_dst() might come from some packet schedulers or classifiers. This patch adds new helper to cleanly express needs of various drivers or qdiscs/classifiers. Drivers that need skb_dst() in their ndo_start_xmit() should call following helper in their setup instead of the prior : dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; -> netif_keep_dst(dev); Instead of using a single bit, we use two bits, one being eventually rebuilt in bonding/team drivers. The other one, is permanent and blocks IFF_XMIT_DST_RELEASE being rebuilt in bonding/team. Eventually, we could add something smarter later. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: validate skb without holding lockEric Dumazet2014-10-031-33/+28
| | | | | | | | | | | | | | | | | | | | | | | | Validation of skb can be pretty expensive : GSO segmentation and/or checksum computations. We can do this without holding qdisc lock, so that other cpus can queue additional packets. Trick is that requeued packets were already validated, so we carry a boolean so that sch_direct_xmit() can validate a fresh skb list, or directly use an old one. Tested on 40Gb NIC (8 TX queues) and 200 concurrent flows, 48 threads host. Turning TSO on or off had no effect on throughput, only few more cpu cycles. Lock contention on qdisc lock disappeared. Same if disabling TX checksum offload. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: dequeue bulking also pickup GSO/TSO packetsJesper Dangaard Brouer2014-10-031-9/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The TSO and GSO segmented packets already benefit from bulking on their own. The TSO packets have always taken advantage of the only updating the tailptr once for a large packet. The GSO segmented packets have recently taken advantage of bulking xmit_more API, via merge commit 53fda7f7f9e8 ("Merge branch 'xmit_list'"), specifically via commit 7f2e870f2a4 ("net: Move main gso loop out of dev_hard_start_xmit() into helper.") allowing qdisc requeue of remaining list. And via commit ce93718fb7cd ("net: Don't keep around original SKB when we software segment GSO frames."). This patch allow further bulking of TSO/GSO packets together, when dequeueing from the qdisc. Testing: Measuring HoL (Head-of-Line) blocking for TSO and GSO, with netperf-wrapper. Bulking several TSO show no performance regressions (requeues were in the area 32 requeues/sec). Bulking several GSOs does show small regression or very small improvement (requeues were in the area 8000 requeues/sec). Using ixgbe 10Gbit/s with GSO bulking, we can measure some additional latency. Base-case, which is "normal" GSO bulking, sees varying high-prio queue delay between 0.38ms to 0.47ms. Bulking several GSOs together, result in a stable high-prio queue delay of 0.50ms. Using igb at 100Mbit/s with GSO bulking, shows an improvement. Base-case sees varying high-prio queue delay between 2.23ms to 2.35ms Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUEJesper Dangaard Brouer2014-10-031-2/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on DaveM's recent API work on dev_hard_start_xmit(), that allows sending/processing an entire skb list. This patch implements qdisc bulk dequeue, by allowing multiple packets to be dequeued in dequeue_skb(). The optimization principle for this is two fold, (1) to amortize locking cost and (2) avoid expensive tailptr update for notifying HW. (1) Several packets are dequeued while holding the qdisc root_lock, amortizing locking cost over several packet. The dequeued SKB list is processed under the TXQ lock in dev_hard_start_xmit(), thus also amortizing the cost of the TXQ lock. (2) Further more, dev_hard_start_xmit() will utilize the skb->xmit_more API to delay HW tailptr update, which also reduces the cost per packet. One restriction of the new API is that every SKB must belong to the same TXQ. This patch takes the easy way out, by restricting bulk dequeue to qdisc's with the TCQ_F_ONETXQUEUE flag, that specifies the qdisc only have attached a single TXQ. Some detail about the flow; dev_hard_start_xmit() will process the skb list, and transmit packets individually towards the driver (see xmit_one()). In case the driver stops midway in the list, the remaining skb list is returned by dev_hard_start_xmit(). In sch_direct_xmit() this returned list is requeued by dev_requeue_skb(). To avoid overshooting the HW limits, which results in requeuing, the patch limits the amount of bytes dequeued, based on the drivers BQL limits. In-effect bulking will only happen for BQL enabled drivers. Small amounts for extra HoL blocking (2x MTU/0.24ms) were measured at 100Mbit/s, with bulking 8 packets, but the oscillating nature of the measurement indicate something, like sched latency might be causing this effect. More comparisons show, that this oscillation goes away occationally. Thus, we disregard this artifact completely and remove any "magic" bulking limit. For now, as a conservative approach, stop bulking when seeing TSO and segmented GSO packets. They already benefit from bulking on their own. A followup patch add this, to allow easier bisect-ability for finding regressions. Jointed work with Hannes, Daniel and Florian. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: make bstats per cpu and estimator RCU safeJohn Fastabend2014-09-301-0/+3
| | | | | | | | | | | | | | | | | In order to run qdisc's without locking statistics and estimators need to be handled correctly. To resolve bstats make the statistics per cpu. And because this is only needed for qdiscs that are running without locks which is not the case for most qdiscs in the near future only create percpu stats when qdiscs set the TCQ_F_CPUSTATS flag. Next because estimators use the bstats to calculate packets per second and bytes per second the estimator code paths are updated to use the per cpu statistics. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: sched: use __skb_queue_head_init() where applicableEric Dumazet2014-09-191-1/+1
| | | | | | | | | | | pfifo_fast and htb use skb lists, without needing their spinlocks. (They instead use the standard qdisc lock) We can use __skb_queue_head_init() instead of skb_queue_head_init() to be consistent. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: qdisc: use rcu prefix and silence sparse warningsJohn Fastabend2014-09-131-2/+2
| | | | | | | | | | | | | | | Add __rcu notation to qdisc handling by doing this we can make smatch output more legible. And anyways some of the cases should be using rcu_dereference() see qdisc_all_tx_empty(), qdisc_tx_chainging(), and so on. Also *wake_queue() API is commonly called from driver timer routines without rcu lock or rtnl lock. So I added rcu_read_lock() blocks around netif_wake_subqueue and netif_tx_wake_queue. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: exit case fixes for skb list handling in qdisc layerJesper Dangaard Brouer2014-09-031-2/+2
| | | | | | | | | | | | | | | More minor fixes to merge commit 53fda7f7f9e (Merge branch 'xmit_list') that allows us to work with a list of SKBs. Fixing exit cases in qdisc_reset() and qdisc_destroy(), where a leftover requeued SKB (qdisc->gso_skb) can have the potential of being a skb list, thus use kfree_skb_list(). This is a followup to commit 10770bc2d1 ("qdisc: adjustments for API allowing skb list xmits"). Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: adjustments for API allowing skb list xmitsJesper Dangaard Brouer2014-09-021-4/+4
| | | | | | | | | | | | Minor adjustments for merge commit 53fda7f7f9e (Merge branch 'xmit_list') that allows us to work with a list of SKBs. Update code doc to function sch_direct_xmit(). In handle_dev_cpu_collision() use kfree_skb_list() in error handling. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Don't keep around original SKB when we software segment GSO frames.David S. Miller2014-09-011-1/+1
| | | | | | | Just maintain the list properly by returning the head of the remaining SKB list from dev_hard_start_xmit(). Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Validate xmit SKBs right when we pull them out of the qdisc.David S. Miller2014-09-011-1/+4
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* net: add skb_get_tx_queue() helperDaniel Borkmann2014-08-291-2/+4
| | | | | | | | Replace occurences of skb_get_queue_mapping() and follow-up netdev_get_tx_queue() with an actual helper function. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix some typos in commentYing Xue2014-07-011-2/+2
| | | | | | | | | | | In commit 371121057607e3127e19b3fa094330181b5b031e("net: QDISC_STATE_RUNNING dont need atomic bit ops") the __QDISC_STATE_RUNNING is renamed to __QDISC___STATE_RUNNING, but the old names existing in comment are not replaced with the new name completely. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net-sysfs: expose number of carrier on/off changesdavid decotigny2014-03-311-0/+2
| | | | | | | | | | | | | | | | | This allows to monitor carrier on/off transitions and detect link flapping issues: - new /sys/class/net/X/carrier_changes - new rtnetlink IFLA_CARRIER_CHANGES (getlink) Tested: - grep . /sys/class/net/*/carrier_changes + ip link set dev X down/up + plug/unplug cable - updated iproute2: prints IFLA_CARRIER_CHANGES - iproute2 20121211-2 (debian): unchanged behavior Signed-off-by: David Decotigny <decot@googlers.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2014-01-141-1/+1
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| * net: core: explicitly select a txq before doing l2 forwardingJason Wang2014-01-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the tx queue were selected implicitly in ndo_dfwd_start_xmit(). The will cause several issues: - NETIF_F_LLTX were removed for macvlan, so txq lock were done for macvlan instead of lower device which misses the necessary txq synchronization for lower device such as txq stopping or frozen required by dev watchdog or control path. - dev_hard_start_xmit() was called with NULL txq which bypasses the net device watchdog. - dev_hard_start_xmit() does not check txq everywhere which will lead a crash when tso is disabled for lower device. Fix this by explicitly introducing a new param for .ndo_select_queue() for just selecting queues in the case of l2 forwarding offload. netdev_pick_tx() was also extended to accept this parameter and dev_queue_xmit_accel() was used to do l2 forwarding transmission. With this fixes, NETIF_F_LLTX could be preserved for macvlan and there's no need to check txq against NULL in dev_hard_start_xmit(). Also there's no need to keep a dedicated ndo_dfwd_start_xmit() and we can just reuse the code of dev_queue_xmit() to do the transmission. In the future, it was also required for macvtap l2 forwarding support since it provides a necessary synchronization method. Cc: John Fastabend <john.r.fastabend@intel.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: e1000-devel@lists.sourceforge.net Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | pkt_sched: set root qdisc before change() in attach_default_qdiscs()Eric Dumazet2013-12-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After commit 95dc19299f74 ("pkt_sched: give visibility to mq slave qdiscs") we call disc_list_add() while the device qdisc might be the noop_qdisc one. This shows up as duplicates in "tc qdisc show", as all inactive devices point to noop_qdisc. Fix this by setting dev->qdisc to the new qdisc before calling ops->change() in attach_default_qdiscs() Add a WARN_ON_ONCE() to catch any future similar problem. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net_sched: change "foo* bar" to "foo *bar"Yang Yingliang2013-12-101-2/+2
|/ | | | | | | "foo* bar" or "foo * bar" should be "foo *bar". Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Add layer 2 hardware acceleration operations for macvlan devicesJohn Fastabend2013-11-071-1/+1
| | | | | | | | | | | | | | | Add a operations structure that allows a network interface to export the fact that it supports package forwarding in hardware between physical interfaces and other mac layer devices assigned to it (such as macvlans). This operaions structure can be used by virtual mac devices to bypass software switching so that forwarding can be done in hardware more efficiently. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Andy Gospodarek <andy@greyhouse.net> CC: "David S. Miller" <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Separate the close_list and the unreg_list v2Eric W. Biederman2013-10-071-3/+3
| | | | | | | | | | | | | | | | | | Separate the unreg_list and the close_list in dev_close_many preventing dev_close_many from permuting the unreg_list. The permutations of the unreg_list have resulted in cases where the loopback device is accessed it has been freed in code such as dst_ifdown. Resulting in subtle memory corruption. This is the second bug from sharing the storage between the close_list and the unreg_list. The issues that crop up with sharing are apparently too subtle to show up in normal testing or usage, so let's forget about being clever and use two separate lists. v2: Make all callers pass in a close_list to dev_close_many Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net_sched: add u64 rate to psched_ratecfg_precompute()Eric Dumazet2013-09-201-2/+3
| | | | | | | | | | | | | Add an extra u64 rate parameter to psched_ratecfg_precompute() so that some qdisc can opt-in for 64bit rates in the future, to overcome the ~34 Gbits limit. psched_ratecfg_getrate() reports a legacy structure to tc utility, so if actual rate is above the 32bit rate field, cap it to the 34Gbit limit. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: fix build with !CONFIG_NET_SCHEDstephen hemminger2013-08-311-0/+4
| | | | | | | | | Multiqueue scheduler refers to default_qdisc_ops; therefore the variable definition needs to be moved to handle case where net scheduler API is not available. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* qdisc: make args to qdisc_create_default conststephen hemminger2013-08-311-2/+3
| | | | | | | Fixes warnings introduced by the qdisc default patch. Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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