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2018-06-24net_sched: remove unused htb drop_listCong Wang1-13/+0
After commit a09ceb0e0814 ("sched: remove qdisc->drop"), it is no longer used. Cc: Florian Westphal <fw@strlen.de> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-01net: sched: do not emit messages while holding spinlockLi RongQing1-4/+7
move messages emitting out of sch_tree_lock to avoid holding this lock too long. Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sch: api: add extack support in qdisc_create_dfltAlexander Aring1-4/+5
This patch adds extack support for the function qdisc_create_dflt which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why qdisc_create_dflt failed. The function qdisc_create_dflt will also call an init callback which can fail by any per-qdisc specific handling. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sch: api: add extack support in tcf_block_getAlexander Aring1-2/+2
This patch adds extack support for the function tcf_block_get which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why tcf_block_get failed. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sch: api: add extack support in qdisc_get_rtabAlexander Aring1-2/+4
This patch adds extack support for the function qdisc_get_rtab which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why qdisc_get_rtab failed. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sched: sch: add extack for graft callbackAlexander Aring1-1/+1
This patch adds extack support for graft callback to prepare per-qdisc specific changes for extack. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sched: sch: add extack for block callbackAlexander Aring1-1/+2
This patch adds extack support for block callback to prepare per-qdisc specific changes for extack. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sched: sch: add extack to change classAlexander Aring1-1/+1
This patch adds extack support for class change callback api. This prepares to handle extack support inside each specific class implementation. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-21net: sched: sch: add extack for init callbackAlexander Aring1-1/+2
This patch adds extack support for init callback to prepare per-qdisc specific changes for extack. Cc: David Ahern <dsahern@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Alexander Aring <aring@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-22net: sched: mark expected switch fall-throughsGustavo A. R. Silva1-0/+1
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where we are expecting to fall through. Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-16net: sched: store Qdisc pointer in struct blockJiri Pirko1-2/+2
Prepare for removal of tp->q and store Qdisc pointer in the block structure. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-18net_sched: sch_htb: add per class overlimits counterEric Dumazet1-0/+5
HTB qdisc overlimits counter is properly increased, but we have no per class counter, meaning it is difficult to diagnose HTB problems. This patch adds this counter, visible in "tc -s class show dev eth0", with current iproute2. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Denys Fedoryshchenko <nuclearcat@nuclearcat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-2/+3
Three cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-30sch_htb: fix crash on init failureNikolay Aleksandrov1-2/+3
The commit below added a call to the ->destroy() callback for all qdiscs which failed in their ->init(), but some were not prepared for such change and can't handle partially initialized qdisc. HTB is one of them and if any error occurs before the qdisc watchdog timer and qdisc work are initialized then we can hit either a null ptr deref (timer->base) when canceling in ->destroy or lockdep error info about trying to register a non-static key and a stack dump. So to fix these two move the watchdog timer and workqueue init before anything that can err out. To reproduce userspace needs to send broken htb qdisc create request, tested with a modified tc (q_htb.c). Trace log: [ 2710.897602] BUG: unable to handle kernel NULL pointer dereference at (null) [ 2710.897977] IP: hrtimer_active+0x17/0x8a [ 2710.898174] PGD 58fab067 [ 2710.898175] P4D 58fab067 [ 2710.898353] PUD 586c0067 [ 2710.898531] PMD 0 [ 2710.898710] [ 2710.899045] Oops: 0000 [#1] SMP [ 2710.899232] Modules linked in: [ 2710.899419] CPU: 1 PID: 950 Comm: tc Not tainted 4.13.0-rc6+ #54 [ 2710.899646] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 2710.900035] task: ffff880059ed2700 task.stack: ffff88005ad4c000 [ 2710.900262] RIP: 0010:hrtimer_active+0x17/0x8a [ 2710.900467] RSP: 0018:ffff88005ad4f960 EFLAGS: 00010246 [ 2710.900684] RAX: 0000000000000000 RBX: ffff88003701e298 RCX: 0000000000000000 [ 2710.900933] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88003701e298 [ 2710.901177] RBP: ffff88005ad4f980 R08: 0000000000000001 R09: 0000000000000001 [ 2710.901419] R10: ffff88005ad4f800 R11: 0000000000000400 R12: 0000000000000000 [ 2710.901663] R13: ffff88003701e298 R14: ffffffff822a4540 R15: ffff88005ad4fac0 [ 2710.901907] FS: 00007f2f5e90f740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000 [ 2710.902277] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2710.902500] CR2: 0000000000000000 CR3: 0000000058ca3000 CR4: 00000000000406e0 [ 2710.902744] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2710.902977] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2710.903180] Call Trace: [ 2710.903332] hrtimer_try_to_cancel+0x1a/0x93 [ 2710.903504] hrtimer_cancel+0x15/0x20 [ 2710.903667] qdisc_watchdog_cancel+0x12/0x14 [ 2710.903866] htb_destroy+0x2e/0xf7 [ 2710.904097] qdisc_create+0x377/0x3fd [ 2710.904330] tc_modify_qdisc+0x4d2/0x4fd [ 2710.904511] rtnetlink_rcv_msg+0x188/0x197 [ 2710.904682] ? rcu_read_unlock+0x3e/0x5f [ 2710.904849] ? rtnl_newlink+0x729/0x729 [ 2710.905017] netlink_rcv_skb+0x6c/0xce [ 2710.905183] rtnetlink_rcv+0x23/0x2a [ 2710.905345] netlink_unicast+0x103/0x181 [ 2710.905511] netlink_sendmsg+0x326/0x337 [ 2710.905679] sock_sendmsg_nosec+0x14/0x3f [ 2710.905847] sock_sendmsg+0x29/0x2e [ 2710.906010] ___sys_sendmsg+0x209/0x28b [ 2710.906176] ? do_raw_spin_unlock+0xcd/0xf8 [ 2710.906346] ? _raw_spin_unlock+0x27/0x31 [ 2710.906514] ? __handle_mm_fault+0x651/0xdb1 [ 2710.906685] ? check_chain_key+0xb0/0xfd [ 2710.906855] __sys_sendmsg+0x45/0x63 [ 2710.907018] ? __sys_sendmsg+0x45/0x63 [ 2710.907185] SyS_sendmsg+0x19/0x1b [ 2710.907344] entry_SYSCALL_64_fastpath+0x23/0xc2 Note that probably this bug goes further back because the default qdisc handling always calls ->destroy on init failure too. Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-25net_sched: remove tc class reference countingWANG Cong1-26/+7
For TC classes, their ->get() and ->put() are always paired, and the reference counting is completely useless, because: 1) For class modification and dumping paths, we already hold RTNL lock, so all of these ->get(),->change(),->put() are atomic. 2) For filter bindiing/unbinding, we use other reference counter than this one, and they should have RTNL lock too. 3) For ->qlen_notify(), it is special because it is called on ->enqueue() path, but we already hold qdisc tree lock there, and we hold this tree lock when graft or delete the class too, so it should not be gone or changed until we release the tree lock. Therefore, this patch removes ->get() and ->put(), but: 1) Adds a new ->find() to find the pointer to a class by classid, no refcnt. 2) Move the original class destroy upon the last refcnt into ->delete(), right after releasing tree lock. This is fine because the class is already removed from hash when holding the lock. For those who also use ->put() as ->unbind(), just rename them to reflect this change. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-16net_sched: call qlen_notify only if child qdisc is emptyKonstantin Khlebnikov1-2/+1
This callback is used for deactivating class in parent qdisc. This is cheaper to test queue length right here. Also this allows to catch draining screwed backlog and prevent second deactivation of already inactive parent class which will crash kernel for sure. Kernel with print warning at destruction of child qdisc where no packets but backlog is not zero. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-15net_sched: reset pointers to tcf blocks in classful qdiscs' destructorsKonstantin Khlebnikov1-1/+3
Traffic filters could keep direct pointers to classes in classful qdisc, thus qdisc destruction first removes all filters before freeing classes. Class destruction methods also tries to free attached filters but now this isn't safe because tcf_block_put() unlike to tcf_destroy_chain() cannot be called second time. This patch set class->block to NULL after first tcf_block_put() and turn second call into no-op. Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure") Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-06net: sched: introduce a TRAP control actionJiri Pirko1-0/+1
There is need to instruct the HW offloaded path to push certain matched packets to cpu/kernel for further analysis. So this patch introduces a new TRAP control action to TC. For kernel datapath, this action does not make much sense. So with the same logic as in HW, new TRAP behaves similar to STOLEN. The skb is just dropped in the datapath (and virtually ejected to an upper level, which does not exist in case of kernel). Signed-off-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Yotam Gigi <yotamg@mellanox.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17net: sched: introduce tcf block infractructureJiri Pirko1-8/+18
Currently, the filter chains are direcly put into the private structures of qdiscs. In order to be able to have multiple chains per qdisc and to allow filter chains sharing among qdiscs, there is a need for common object that would hold the chains. This introduces such object and calls it "tcf_block". Helpers to get and put the blocks are provided to be called from individual qdisc code. Also, the original filter_list pointers are left in qdisc privs to allow the entry into tcf_block processing without any added overhead of possible multiple pointer dereference on fast path. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-17net: sched: move tc_classify function to cls_api.cJiri Pirko1-1/+1
Move tc_classify function to cls_api.c where it belongs, rename it to fit the namespace. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-13netlink: pass extended ACK struct to parsing functionsJohannes Berg1-2/+2
Pass the new extended ACK reporting struct to all of the generic netlink parsing functions. For now, pass NULL in almost all callers (except for some in the core.) Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-12net: sched: make default fifo qdiscs appear in the dumpJiri Kosina1-0/+2
The original reason [1] for having hidden qdiscs (potential scalability issues in qdisc_match_from_root() with single linked list in case of large amount of qdiscs) has been invalidated by 59cc1f61f0 ("net: sched: convert qdisc linked list to hashtable"). This allows us for bringing more clarity and determinism into the dump by making default pfifo qdiscs visible. We're not turning this on by default though, at it was deemed [2] too intrusive / unnecessary change of default behavior towards userspace. Instead, TCA_DUMP_INVISIBLE netlink attribute is introduced, which allows applications to request complete qdisc hierarchy dump, including the ones that have always been implicit/invisible. Singleton noop_qdisc stays invisible, as teaching the whole infrastructure about singletons would require quite some surgery with very little gain (seeing no qdisc or seeing noop qdisc in the dump is probably setting the same user expectation). [1] http://lkml.kernel.org/r/1460732328.10638.74.camel@edumazet-glaptop3.roam.corp.google.com [2] http://lkml.kernel.org/r/20161021.105935.1907696543877061916.davem@davemloft.net Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-10sched: move tcf_proto_destroy and tcf_destroy_chain helpers into cls_apiJiri Pirko1-0/+1
Creation is done in this file, move destruction to be at the same place. Signed-off-by: Jiri Pirko <jiri@mellanox.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-05net_sched: gen_estimator: complete rewrite of rate estimatorsEric Dumazet1-3/+3
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>
2016-10-26sch_htb: do not report fake rate estimatorsEric Dumazet1-1/+1
When I prepared commit d250a5f90e53 ("pkt_sched: gen_estimator: Dont report fake rate estimators"), htb still had an implicit rate estimator for all its classes. Then later, I made this rate estimator optional in commit 64153ce0a7b6 ("net_sched: htb: do not setup default rate estimators"), but I forgot to update htb use of gnet_stats_copy_rate_est() After this patch, "tc -s qdisc ..." no longer report fake rate estimators for HTB classes. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-19sched: add and use qdisc_skb_head helpersFlorian Westphal1-4/+20
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>
2016-07-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-2/+4
Just several instances of overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-18net/sched/sch_htb: clamp xstats tokens to fit into 32-bit intKonstantin Khlebnikov1-2/+4
In kernel HTB keeps tokens in signed 64-bit in nanoseconds. In netlink protocol these values are converted into pshed ticks (64ns for now) and truncated to 32-bit. In struct tc_htb_xstats fields "tokens" and "ctokens" are declared as unsigned 32-bit but they could be negative thus tool 'tc' prints them as signed. Big values loose higher bits and/or become negative. This patch clamps tokens in xstat into range from INT_MIN to INT_MAX. In this way it's easier to understand what's going on here. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+2
Several cases of overlapping changes, except the packet scheduler conflicts which deal with the addition of the free list parameter to qdisc_enqueue(). Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-25net_sched: sch_htb: export class backlog in dumpsEric Dumazet1-4/+10
We already get child qdisc qlen, we also can get its backlog so that class dumps can report it. Also replace qstats by a single drop counter, but move it in a separate cache line so that drops do not dirty useful cache lines. Tested: $ tc -s cl sh dev eth0 class htb 1:1 root leaf 3: prio 0 rate 1Gbit ceil 1Gbit burst 500000b cburst 500000b Sent 2183346912 bytes 9021815 pkt (dropped 2340774, overlimits 0 requeues 0) rate 1001Mbit 517543pps backlog 120758b 499p requeues 0 lended: 9021770 borrowed: 0 giants: 0 tokens: 9 ctokens: 9 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-25net_sched: drop packets after root qdisc lock is releasedEric Dumazet1-4/+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>
2016-06-15htb: call qdisc_root with rcu read lock heldFlorian Westphal1-0/+2
saw a debug splat: net/include/net/sch_generic.h:287 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by kworker/2:1/710: #0: ("events"){.+.+.+}, at: [<ffffffff8106ca1d>] #1: ((&q->work)){+.+...}, at: [<ffffffff8106ca1d>] process_one_work+0x14d/0x690 Workqueue: events htb_work_func Call Trace: [<ffffffff812dc763>] dump_stack+0x85/0xc2 [<ffffffff8109fee7>] lockdep_rcu_suspicious+0xe7/0x120 [<ffffffff814ced47>] htb_work_func+0x67/0x70 Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-15net_sched: sch_htb: defer skb freeingEric Dumazet1-2/+2
Both htb_reset() and htb_destroy() can use __qdisc_reset_queue() instead of __skb_queue_purge() to defer skb freeing of internal queues. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-10net_sched: remove generic throttled managementEric Dumazet1-2/+1
__QDISC_STATE_THROTTLED bit manipulation is rather expensive for HTB and few others. I already removed it for sch_fq in commit f2600cf02b5b ("net: sched: avoid costly atomic operation in fq_dequeue()") and so far nobody complained. When one ore more packets are stuck in one or more throttled HTB class, a htb dequeue() performs two atomic operations to clear/set __QDISC_STATE_THROTTLED bit, while root qdisc lock is held. Removing this pair of atomic operations bring me a 8 % performance increase on 200 TCP_RR tests, in presence of throttled classes. This patch has no side effect, since nothing actually uses disc_is_throttled() anymore. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-08sched: remove qdisc->dropFlorian Westphal1-26/+0
after removal of TCA_CBQ_OVL_STRATEGY from cbq scheduler, there are no more callers of ->drop() outside of other ->drop functions, i.e. nothing calls them. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-07net: sched: do not acquire qdisc spinlock in qdisc/class stats dumpEric Dumazet1-5/+6
Large tc dumps (tc -s {qdisc|class} sh dev ethX) done by Google BwE host agent [1] are problematic at scale : For each qdisc/class found in the dump, we currently lock the root qdisc spinlock in order to get stats. Sampling stats every 5 seconds from thousands of HTB classes is a challenge when the root qdisc spinlock is under high pressure. Not only the dumps take time, they also slow down the fast path (queue/dequeue packets) by 10 % to 20 % in some cases. An audit of existing qdiscs showed that sch_fq_codel is the only qdisc that might need the qdisc lock in fq_codel_dump_stats() and fq_codel_dump_class_stats() In v2 of this patch, I now use the Qdisc running seqcount to provide consistent reads of packets/bytes counters, regardless of 32/64 bit arches. I also changed rate estimators to use the same infrastructure so that they no longer need to lock root qdisc lock. [1] http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/43838.pdf Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Kevin Athey <kda@google.com> Cc: Xiaotian Pei <xiaotian@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-24net_sched: avoid too many hrtimer_start() callsEric Dumazet1-10/+3
I found a serious performance bug in packet schedulers using hrtimers. sch_htb and sch_fq are definitely impacted by this problem. We constantly rearm high resolution timers if some packets are throttled in one (or more) class, and other packets are flying through qdisc on another (non throttled) class. hrtimer_start() does not have the mod_timer() trick of doing nothing if expires value does not change : if (timer_pending(timer) && timer->expires == expires) return 1; This issue is particularly visible when multiple cpus can queue/dequeue packets on the same qdisc, as hrtimer code has to lock a remote base. I used following fix : 1) Change htb to use qdisc_watchdog_schedule_ns() instead of open-coding it. 2) Cache watchdog prior expiration. hrtimer might provide this, but I prefer to not rely on some hrtimer internal. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25sched: use nla_put_u64_64bit()Nicolas Dichtel1-2/+4
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29sch_htb: update backlog as wellWANG Cong1-1/+4
We saw qlen!=0 but backlog==0 on our production machine: qdisc htb 1: dev eth0 root refcnt 2 r2q 10 default 1 direct_packets_stat 0 ver 3.17 Sent 172680457356 bytes 222469449 pkt (dropped 0, overlimits 123575834 requeues 0) backlog 0b 72p requeues 0 The problem is we only count qlen for HTB qdisc but not backlog. We need to update backlog too when we update qlen, so that we can at least know the average packet length. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29net_sched: update hierarchical backlog tooWANG Cong1-4/+6
When the bottom qdisc decides to, for example, drop some packet, it calls qdisc_tree_decrease_qlen() to update the queue length for all its ancestors, we need to update the backlog too to keep the stats on root qdisc accurate. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29net_sched: introduce qdisc_replace() helperWANG Cong1-8/+1
Remove nearly duplicated code and prepare for the following patch. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-27net: sched: consolidate tc_classify{,_compat}Daniel Borkmann1-1/+1
For classifiers getting invoked via tc_classify(), we always need an extra function call into tc_classify_compat(), as both are being exported as symbols and tc_classify() itself doesn't do much except handling of reclassifications when tp->classify() returned with TC_ACT_RECLASSIFY. CBQ and ATM are the only qdiscs that directly call into tc_classify_compat(), all others use tc_classify(). When tc actions are being configured out in the kernel, tc_classify() effectively does nothing besides delegating. We could spare this layer and consolidate both functions. pktgen on single CPU constantly pushing skbs directly into the netif_receive_skb() path with a dummy classifier on ingress qdisc attached, improves slightly from 22.3Mpps to 23.1Mpps. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-18net: sched: drop all special handling of tx_queue_len == 0Phil Sutter1-4/+2
Those were all workarounds for the formerly double meaning of tx_queue_len, which broke scheduling algorithms if untreated. Now that all in-tree drivers have been converted away from setting tx_queue_len = 0, it should be safe to drop these workarounds for categorically broken setups. Signed-off-by: Phil Sutter <phil@nwl.cc> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30net: sched: enable per cpu qstatsJohn Fastabend1-1/+1
After previous patches to simplify qstats the qstats can be made per cpu with a packed union in Qdisc struct. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30net: sched: restrict use of qstats qlenJohn Fastabend1-2/+3
This removes the use of qstats->qlen variable from the classifiers and makes it an explicit argument to gnet_stats_copy_queue(). The qlen represents the qdisc queue length and is packed into the qstats at the last moment before passnig to user space. By handling it explicitely we avoid, in the percpu stats case, having to figure out which per_cpu variable to put it in. It would probably be best to remove it from qstats completely but qstats is a user space ABI and can't be broken. A future patch could make an internal only qstats structure that would avoid having to allocate an additional u32 variable on the Qdisc struct. This would make the qstats struct 128bits instead of 128+32. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30net: sched: implement qstat helper routinesJohn Fastabend1-3/+3
This adds helpers to manipulate qstats logic and replaces locations that touch the counters directly. This simplifies future patches to push qstats onto per cpu counters. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30net: sched: make bstats per cpu and estimator RCU safeJohn Fastabend1-4/+8
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>
2014-09-26net: sched: use pinned timersEric Dumazet1-1/+1
While using a MQ + NETEM setup, I had confirmation that the default timer migration ( /proc/sys/kernel/timer_migration ) is killing us. Installing this on a receiver side of a TCP_STREAM test, (NIC has 8 TX queues) : EST="est 1sec 4sec" for ETH in eth1 do tc qd del dev $ETH root 2>/dev/null tc qd add dev $ETH root handle 1: mq tc qd add dev $ETH parent 1:1 $EST netem limit 70000 delay 6ms tc qd add dev $ETH parent 1:2 $EST netem limit 70000 delay 8ms tc qd add dev $ETH parent 1:3 $EST netem limit 70000 delay 10ms tc qd add dev $ETH parent 1:4 $EST netem limit 70000 delay 12ms tc qd add dev $ETH parent 1:5 $EST netem limit 70000 delay 14ms tc qd add dev $ETH parent 1:6 $EST netem limit 70000 delay 16ms tc qd add dev $ETH parent 1:7 $EST netem limit 80000 delay 18ms tc qd add dev $ETH parent 1:8 $EST netem limit 90000 delay 20ms done We can see that timers get migrated into a single cpu, presumably idle at the time timers are set up. Then all qdisc dequeues run from this cpu and huge lock contention happens. This single cpu is stuck in softirq mode and cannot dequeue fast enough. 39.24% [kernel] [k] _raw_spin_lock 2.65% [kernel] [k] netem_enqueue 1.80% [kernel] [k] netem_dequeue 1.63% [kernel] [k] copy_user_enhanced_fast_string 1.45% [kernel] [k] _raw_spin_lock_bh By pinning qdisc timers on the cpu running the qdisc, we respect proper XPS setting and remove this lock contention. 5.84% [kernel] [k] netem_enqueue 4.83% [kernel] [k] _raw_spin_lock 2.92% [kernel] [k] copy_user_enhanced_fast_string Current Qdiscs that benefit from this change are : netem, cbq, fq, hfsc, tbf, htb. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-19net: sched: use __skb_queue_head_init() where applicableEric Dumazet1-1/+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>
2014-09-13net: rcu-ify tcf_protoJohn Fastabend1-7/+8
rcu'ify tcf_proto this allows calling tc_classify() without holding any locks. Updaters are protected by RTNL. This patch prepares the core net_sched infrastracture for running the classifier/action chains without holding the qdisc lock however it does nothing to ensure cls_xxx and act_xxx types also work without locking. Additional patches are required to address the fall out. 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>
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