kernel/linux.git/include/uapi/linux/pkt_sched.h, branch v5.10.258

fq_codel: reject silly quantum parameters

2021-09-22T10:28:05+00:00

[ Upstream commit c7c5e6ff533fe1f9afef7d2fa46678987a1335a7 ] syzbot found that forcing a big quantum attribute would crash hosts fast, essentially using this: tc qd replace dev eth0 root fq_codel quantum 4294967295 This is because fq_codel_dequeue() would have to loop ~2^31 times in : if (flow->deficit <= 0) { flow->deficit += q->quantum; list_move_tail(&flow->flowchain, &q->old_flows); goto begin; } SFQ max quantum is 2^19 (half a megabyte) Lets adopt a max quantum of one megabyte for FQ_CODEL. Fixes: 4b549a2ef4be ("fq_codel: Fair Queue Codel AQM") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: sched: sch_red: Add qevents "early_drop" and "mark"

2020-06-30T00:08:28+00:00

In order to allow acting on dropped and/or ECN-marked packets, add two new qevents to the RED qdisc: "early_drop" and "mark". Filters attached at "early_drop" block are executed as packets are early-dropped, those attached at the "mark" block are executed as packets are ECN-marked. Two new attributes are introduced: TCA_RED_EARLY_DROP_BLOCK with the block index for the "early_drop" qevent, and TCA_RED_MARK_BLOCK for the "mark" qevent. Absence of these attributes signifies "don't care": no block is allocated in that case, or the existing blocks are left intact in case of the change callback. For purposes of offloading, blocks attached to these qevents appear with newly-introduced binder types, FLOW_BLOCK_BINDER_TYPE_RED_EARLY_DROP and FLOW_BLOCK_BINDER_TYPE_RED_MARK. Signed-off-by: Petr Machata Signed-off-by: David S. Miller

net_sched: sch_fq: add horizon attribute

2020-05-04T18:56:17+00:00

QUIC servers would like to use SO_TXTIME, without having CAP_NET_ADMIN, to efficiently pace UDP packets. As far as sch_fq is concerned, we need to add safety checks, so that a buggy application does not fill the qdisc with packets having delivery time far in the future. This patch adds a configurable horizon (default: 10 seconds), and a configurable policy when a packet is beyond the horizon at enqueue() time: - either drop the packet (default policy) - or cap its delivery time to the horizon. $ tc -s -d qd sh dev eth0 qdisc fq 8022: root refcnt 257 limit 10000p flow_limit 100p buckets 1024 orphan_mask 1023 quantum 10Kb initial_quantum 51160b low_rate_threshold 550Kbit refill_delay 40.0ms timer_slack 10.000us horizon 10.000s Sent 1234215879 bytes 837099 pkt (dropped 21, overlimits 0 requeues 6) backlog 0b 0p requeues 6 flows 1191 (inactive 1177 throttled 0) gc 0 highprio 0 throttled 692 latency 11.480us pkts_too_long 0 alloc_errors 0 horizon_drops 21 horizon_caps 0 v2: fixed an overflow on 32bit kernels in fq_init(), reported by kbuild test robot Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Signed-off-by: David S. Miller

taprio: do not use BIT() in TCA_TAPRIO_ATTR_FLAG_* definitions

2020-03-27T03:08:45+00:00

BIT() macro definition is internal to the Linux kernel and is not to be used in UAPI headers; replace its usage with the _BITUL() macro that is already used elsewhere in the header. Fixes: 9c66d1564676 ("taprio: Add support for hardware offloading") Signed-off-by: Eugene Syromiatnikov Acked-by: Vladimir Oltean Signed-off-by: David S. Miller

net_sched: sch_fq: enable use of hrtimer slack

2020-03-18T04:16:35+00:00

Add a new attribute to control the fq qdisc hrtimer slack. Default is set to 10 usec. When/if packets are throttled, fq set up an hrtimer that can lead to one interrupt per packet in the throttled queue. By using a timer slack, we allow better use of timer interrupts, by giving them a chance to call multiple timer callbacks at each hardware interrupt. Also, giving a slack allows FQ to dequeue batches of packets instead of a single one, thus increasing xmit_more efficiency. This has no negative effect on the rate a TCP flow can sustain, since each TCP flow maintains its own precise vtime (tp->tcp_wstamp_ns) v2: added strict netlink checking (as feedback from Jakub Kicinski) Tested: 1000 concurrent flows all using paced packets. 1,000,000 packets sent per second. Before the patch : $ vmstat 2 10 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 60726784 23628 3485992 0 0 138 1 977 535 0 12 87 0 0 0 0 0 60714700 23628 3485628 0 0 0 0 1568827 26462 0 22 78 0 0 1 0 0 60716012 23628 3485656 0 0 0 0 1570034 26216 0 22 78 0 0 0 0 0 60722420 23628 3485492 0 0 0 0 1567230 26424 0 22 78 0 0 0 0 0 60727484 23628 3485556 0 0 0 0 1568220 26200 0 22 78 0 0 2 0 0 60718900 23628 3485380 0 0 0 40 1564721 26630 0 22 78 0 0 2 0 0 60718096 23628 3485332 0 0 0 0 1562593 26432 0 22 78 0 0 0 0 0 60719608 23628 3485064 0 0 0 0 1563806 26238 0 22 78 0 0 1 0 0 60722876 23628 3485236 0 0 0 130 1565874 26566 0 22 78 0 0 1 0 0 60722752 23628 3484908 0 0 0 0 1567646 26247 0 22 78 0 0 After the patch, slack of 10 usec, we can see a reduction of interrupts per second, and a small decrease of reported cpu usage. $ vmstat 2 10 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 1 0 0 60722564 23628 3484728 0 0 133 1 696 545 0 13 87 0 0 1 0 0 60722568 23628 3484824 0 0 0 0 977278 25469 0 20 80 0 0 0 0 0 60716396 23628 3484764 0 0 0 0 979997 25326 0 20 80 0 0 0 0 0 60713844 23628 3484960 0 0 0 0 981394 25249 0 20 80 0 0 2 0 0 60720468 23628 3484916 0 0 0 0 982860 25062 0 20 80 0 0 1 0 0 60721236 23628 3484856 0 0 0 0 982867 25100 0 20 80 0 0 1 0 0 60722400 23628 3484456 0 0 0 8 982698 25303 0 20 80 0 0 0 0 0 60715396 23628 3484428 0 0 0 0 981777 25176 0 20 80 0 0 0 0 0 60716520 23628 3486544 0 0 0 36 978965 27857 0 21 79 0 0 0 0 0 60719592 23628 3486516 0 0 0 22 977318 25106 0 20 80 0 0 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: sched: RED: Introduce an ECN nodrop mode

2020-03-15T04:03:46+00:00

When the RED Qdisc is currently configured to enable ECN, the RED algorithm is used to decide whether a certain SKB should be marked. If that SKB is not ECN-capable, it is early-dropped. It is also possible to keep all traffic in the queue, and just mark the ECN-capable subset of it, as appropriate under the RED algorithm. Some switches support this mode, and some installations make use of it. To that end, add a new RED flag, TC_RED_NODROP. When the Qdisc is configured with this flag, non-ECT traffic is enqueued instead of being early-dropped. Signed-off-by: Petr Machata Reviewed-by: Jakub Kicinski Signed-off-by: David S. Miller

net: sched: Allow extending set of supported RED flags

2020-03-15T04:03:46+00:00

The qdiscs RED, GRED, SFQ and CHOKE use different subsets of the same pool of global RED flags. These are passed in tc_red_qopt.flags. However none of these qdiscs validate the flag field, and just copy it over wholesale to internal structures, and later dump it back. (An exception is GRED, which does validate for VQs -- however not for the main setup.) A broken userspace can therefore configure a qdisc with arbitrary unsupported flags, and later expect to see the flags on qdisc dump. The current ABI therefore allows storage of several bits of custom data to qdisc instances of the types mentioned above. How many bits, depends on which flags are meaningful for the qdisc in question. E.g. SFQ recognizes flags ECN and HARDDROP, and the rest is not interpreted. If SFQ ever needs to support ADAPTATIVE, it needs another way of doing it, and at the same time it needs to retain the possibility to store 6 bits of uninterpreted data. Likewise RED, which adds a new flag later in this patchset. To that end, this patch adds a new function, red_get_flags(), to split the passed flags of RED-like qdiscs to flags and user bits, and red_validate_flags() to validate the resulting configuration. It further adds a new attribute, TCA_RED_FLAGS, to pass arbitrary flags. Signed-off-by: Petr Machata Reviewed-by: Jakub Kicinski Signed-off-by: David S. Miller

net: sched: add Flow Queue PIE packet scheduler

2020-01-23T10:38:31+00:00

Principles: - Packets are classified on flows. - This is a Stochastic model (as we use a hash, several flows might be hashed to the same slot) - Each flow has a PIE managed queue. - Flows are linked onto two (Round Robin) lists, so that new flows have priority on old ones. - For a given flow, packets are not reordered. - Drops during enqueue only. - ECN capability is off by default. - ECN threshold (if ECN is enabled) is at 10% by default. - Uses timestamps to calculate queue delay by default. Usage: tc qdisc ... fq_pie [ limit PACKETS ] [ flows NUMBER ] [ target TIME ] [ tupdate TIME ] [ alpha NUMBER ] [ beta NUMBER ] [ quantum BYTES ] [ memory_limit BYTES ] [ ecnprob PERCENTAGE ] [ [no]ecn ] [ [no]bytemode ] [ [no_]dq_rate_estimator ] defaults: limit: 10240 packets, flows: 1024 target: 15 ms, tupdate: 15 ms (in jiffies) alpha: 1/8, beta : 5/4 quantum: device MTU, memory_limit: 32 Mb ecnprob: 10%, ecn: off bytemode: off, dq_rate_estimator: off Signed-off-by: Mohit P. Tahiliani Signed-off-by: Sachin D. Patil Signed-off-by: V. Saicharan Signed-off-by: Mohit Bhasi Signed-off-by: Leslie Monis Signed-off-by: Gautam Ramakrishnan Signed-off-by: David S. Miller

net: sch_ets: Add a new Qdisc

2019-12-18T21:32:29+00:00

Introduces a new Qdisc, which is based on 802.1Q-2014 wording. It is PRIO-like in how it is configured, meaning one needs to specify how many bands there are, how many are strict and how many are dwrr, quanta for the latter, and priomap. The new Qdisc operates like the PRIO / DRR combo would when configured as per the standard. The strict classes, if any, are tried for traffic first. When there's no traffic in any of the strict queues, the ETS ones (if any) are treated in the same way as in DRR. Signed-off-by: Petr Machata Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: sched: pie: enable timestamp based delay calculation

2019-11-20T20:31:45+00:00

RFC 8033 suggests an alternative approach to calculate the queue delay in PIE by using a timestamp on every enqueued packet. This patch adds an implementation of that approach and sets it as the default method to calculate queue delay. The previous method (based on Little's law) to calculate queue delay is set as optional. Signed-off-by: Gautam Ramakrishnan Signed-off-by: Leslie Monis Signed-off-by: Mohit P. Tahiliani Acked-by: Dave Taht Signed-off-by: David S. Miller