| Age | Commit message (Collapse) | Author |
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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>
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The code using this variable has been commented out in the past as it
was causing issues in upperlimited link-sharing scenarios.
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch simplifies how we update fsc and calculate vt from it - while
keeping the expected functionality identical with how hfsc behaves
curently. It also fixes a certain issue introduced with
a very old patch.
The idea is, that instead of correcting cl_vt before fsc curve update
(rtsc_min) and correcting cl_vt after calculation (rtsc_y2x) to keep
cl_vt local to the current period - we can simply rely on virtual times
and curve values always being in sync - analogously to how rsc and usc
function, except that we use virtual time here.
Why hasn't it been done since the beginning this way ? The likely scenario
(basing on the code trying to correct curves whenever possible) was to
keep the virtual times as small as possible - as they have tendency to
"gallop" forward whenever their siblings and other fair sharing
subtrees are idling. On top of that, current code is subtly bugged, so
cumulative time (without any corrections) is always kept and used in
init_vf() when a new backlog period begins (using cl_cvtoff).
Is cumulative value safe ? Generally yes, though corner cases are easy
to create. For example consider:
1gbit interface
some 100kbit leaf, everything else idle
With current tick (64ns) 1s is 15625000 ticks, but the leaf is alone and
it's virtual time, so in reality it's 10000 times more. ITOW 38 bits are
needed to hold 1 second. 54 - 1 day, 59 - 1 month, 63 - 1 year (all
logarithms rounded up). It's getting somewhat dangerous, but also
requires setup excusing this kind of values not mentioning permanently
backlogged class for a year. In near most extreme case (10gbit, 10kbit
leaf), we have "enough" to hold ~13.6 days in 64 bits.
Well, the issue remains mostly theoretical and cl_cvtoff has been
working fine for all those years. Sensible configuration are de-facto
immune to this issue, and not so sensible can solve it with a cronjob
and its period inversely proportional to the insanity of such setup =)
Now let's explain the subtle bug mentioned earlier.
The issue is related to how offsets are kept and how we calculate
virtual times and update fair service curve(s). The issue itself is
subtle, but easy to observe with long m1 segments. It was introduced in
rather old patch:
Commit 99296150c7: "[NET_SCHED]: O(1) children vtoff adjustment
in HFSC scheduler"
(available in git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git)
Originally when a new backlog period was started, cl_vtoff of each
sibling was updated with cl_cvtmax from past period - naturally moving
all cl_vt to proper starting point. That patch adjusted it so cumulative
offset is kept in the parent, and there is no need for traversing the
list (as any subsequent child activation derives new vt from already
active sibling(s)).
But with this change, cl_vtoff (of each sibling) is no longer persistent
across the inactivity periods, as it's calculated from parent's
cl_cvtoff on a new backlog period, conflicting with the following curve
correction from the previous period:
if (cl->cl_virtual.x == vt) {
cl->cl_virtual.x -= cl->cl_vtoff;
cl->cl_vtoff = 0;
}
This essentially tries to keep curve as if it was local to the period
and resets cl_vtoff (cumulative vt offset of the class) to 0 when
possible (read: when we have an intersection or if a new curve is below
the old one). But then it's recalculated from cl_cvtoff on next active
period. Then rtsc_min() call preceding the above if() doesn't really
do what we expect it to do in such scenario - as it calculates the
minimum of corrected curve (from the previous backlog period) and the
new uncorrected curve (with offset derived from cl_cvtoff).
Example:
tc class add dev $ife parent 1:0 classid 1:1 hfsc ls m2 100mbit ul m2 100mbit
tc class add dev $ife parent 1:1 classid 1:10 hfsc ls m1 80mbit d 10s m2 20mbit
tc class add dev $ife parent 1:1 classid 1:11 hfsc ls m2 20mbit
start B, keep it backlogged, let it run 6s (30s worth of vt as A is idle)
pause B briefly to force cl_cvtoff update in parent (whole 1:1 going idle)
start A, let it run 10s
pause A briefly to force rtsc_min()
At this point we would expect A to continue at 20mbit after a brief
moment of 80mbit. But instead A will use 80mbit for full 10s again. It's
the effect of first correcting A (during 'start A'), and then - after
unpausing - calculating rtsc_min() from old corrected and new uncorrected
curve.
The patch fixes this bug and keepis vt and fsc in sync (virtual times
are cumulative, not local to the backlog period).
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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hfsc_sched is huge (size: 920, cachelines: 15), but we can get it to 14
cachelines by placing level after filter_cnt (covering 4 byte hole) and
reducing period/nactive/flags to u32 (period is just a counter,
incremented when class becomes active -- 2**32 is plenty for this
purpose, also, long is only 32bit wide on 32bit platforms anyway).
cl_vtperiod is exported to userspace via tc_hfsc_stats, but its period
member is already u32, so no precision is lost there either.
Cc: Michal Soltys <soltys@ziu.info>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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cl->cl_vt alone is relative only to the current backlog period, while
the curve operates on cumulative virtual time. This patch adds missing
cl->cl_vtoff.
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When a class is going passive, it should update its cl_vt first
to be consistent with the last dequeue operation.
Otherwise its cl_vt will be one packet behind and parent's cvtmax might
not be updated as well.
One possible side effect is if some class goes passive and subsequently
goes active /without/ its parent going passive - with cl_vt lagging one
packet behind - comparison made in init_vf() will be affected (same
period).
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This is update to:
commit a09ceb0e08140a ("sched: remove qdisc->drop")
That commit removed qdisc->drop, but left alone dlist and droplist
that no longer serve any meaningful purpose.
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The condition can only succeed on wrong configurations.
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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calculated deadline
Realtime scheduling implemented in HFSC uses head of the queue to make
the decision about which packet to schedule next. But in case of any
head drop, the deadline calculated for the previous head is not
necessarily correct for the next head (unless both packets have the same
length).
Thanks to peek() function used during dequeue - which internally is a
dequeue operation - hfsc is almost safe from this issue, as peek()
dequeues and isolates the head storing it temporarily until the real
dequeue happens.
But there is one exception: if after the class activation a drop happens
before the first dequeue operation, there's never a chance to do the
peek().
Adding peek() call in enqueue - if this is the first packet in a new
backlog period AND the scheduler has realtime curve defined - fixes that
one corner case. The 1st hfsc_dequeue() will use that peeked packet,
similarly as every subsequent hfsc_dequeue() call uses packet peeked by
the previous call.
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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>
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__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>
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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>
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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>
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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>
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hfsc updates backlog lazily, that is only when we
dump the stats. This is problematic after we begin to
update backlog in qdisc_tree_reduce_backlog().
Reported-by: Stas Nichiporovich <stasn77@gmail.com>
Tested-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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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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nla_nest_end() already has return skb->len, so replace
return skb->len with return nla_nest_end instead().
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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struct gnet_stats_rate_est contains u32 fields, so the bytes per second
field can wrap at 34360Mbit.
Add a new gnet_stats_rate_est64 structure to get 64bit bps/pps fields,
and switch the kernel to use this structure natively.
This structure is dumped to user space as a new attribute :
TCA_STATS_RATE_EST64
Old tc command will now display the capped bps (to 34360Mbit), instead
of wrapped values, and updated tc command will display correct
information.
Old tc command output, after patch :
eric:~# tc -s -d qd sh dev lo
qdisc pfifo 8001: root refcnt 2 limit 1000p
Sent 80868245400 bytes 1978837 pkt (dropped 0, overlimits 0 requeues 0)
rate 34360Mbit 189696pps backlog 0b 0p requeues 0
This patch carefully reorganizes "struct Qdisc" layout to get optimal
performance on SMP.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Class bytes/packets stats can be misleading because they are updated in
enqueue() while packet might be dropped later.
We already fixed all qdiscs but sch_atm.
This patch makes the final cleanup.
class rate estimators can now match qdisc ones.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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These macros contain a hidden goto, and are thus extremely error
prone and make code hard to audit.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add backlog (byte count) information in hfsc classes and qdisc, so that
"tc -s" can report it to user, instead of 0 values :
qdisc hfsc 1: root refcnt 6 default 20
Sent 45141660 bytes 30545 pkt (dropped 0, overlimits 91751 requeues 0)
rate 1492Kbit 126pps backlog 103226b 74p requeues 0
...
class hfsc 1:20 parent 1:1 leaf 1201: rt m1 0bit d 0us m2 400000bit ls m1 0bit d 0us m2 200000bit
Sent 49534912 bytes 33519 pkt (dropped 0, overlimits 0 requeues 0)
backlog 81822b 56p requeues 0
period 23 work 49451576 bytes rtwork 13277552 bytes level 0
...
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: John A. Sullivan III <jsullivan@opensourcedevel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
net/sched/sch_hfsc.c
net/sched/sch_htb.c
net/sched/sch_tbf.c
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In commit 44b8288308ac9d (net_sched: pfifo_head_drop problem), we fixed
a problem with pfifo_head drops that incorrectly decreased
sch->bstats.bytes and sch->bstats.packets
Several qdiscs (CHOKe, SFQ, pfifo_head, ...) are able to drop a
previously enqueued packet, and bstats cannot be changed, so
bstats/rates are not accurate (over estimated)
This patch changes the qdisc_bstats updates to be done at dequeue() time
instead of enqueue() time. bstats counters no longer account for dropped
frames, and rates are more correct, since enqueue() bursts dont have
effect on dequeue() rate.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In commit 371121057607e (net: QDISC_STATE_RUNNING dont need atomic bit
ops) I moved QDISC_STATE_RUNNING flag to __state container, located in
the cache line containing qdisc lock and often dirtied fields.
I now move TCQ_F_THROTTLED bit too, so that we let first cache line read
mostly, and shared by all cpus. This should speedup HTB/CBQ for example.
Not using test_bit()/__clear_bit()/__test_and_set_bit allows to use an
"unsigned int" for __state container, reducing by 8 bytes Qdisc size.
Introduce helpers to hide implementation details.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Jesper Dangaard Brouer <hawk@diku.dk>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Jamal Hadi Salim <hadi@cyberus.ca>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Cleanup net/sched code to current CodingStyle and practices.
Reduce inline abuse
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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HTB takes into account skb is segmented in stats updates.
Generalize this to all schedulers.
They should use qdisc_bstats_update() helper instead of manipulating
bstats.bytes and bstats.packets
Add bstats_update() helper too for classes that use
gnet_stats_basic_packed fields.
Note : Right now, TCQ_F_CAN_BYPASS shortcurt can be taken only if no
stab is setup on qdisc.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The first parameter dev isn't in use in qdisc_create_dflt().
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch fixes init_vf() function, so on each new backlog period parent's
cl_cfmin is properly updated (including further propgation towards the root),
even if the activated leaf has no upperlimit curve defined.
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch removes from net/ (but not any netfilter files)
all the unnecessary return; statements that precede the
last closing brace of void functions.
It does not remove the returns that are immediately
preceded by a label as gcc doesn't like that.
Done via:
$ grep -rP --include=*.[ch] -l "return;\n}" net/ | \
xargs perl -i -e 'local $/ ; while (<>) { s/\n[ \t\n]+return;\n}/\n}/g; print; }'
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When attaching filters to a class pointing to a class higher up in the
hierarchy, classification may enter an endless loop. Currently this is
prevented for filters that are already resolved, but not for filters
resolved at runtime.
Only allow filters to point downwards in the hierarchy, similar to what
CBQ does.
Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jarek Poplawski a écrit :
>
>
> Hmm... So you made me to do some "real" work here, and guess what?:
> there is one serious checkpatch warning! ;-) Plus, this new parameter
> should be added to the function description. Otherwise:
> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
>
> Thanks,
> Jarek P.
>
> PS: I guess full "Don't" would show we really mean it...
Okay :) Here is the last round, before the night !
Thanks again
[RFC] pkt_sched: gen_estimator: Don't report fake rate estimators
We currently send TCA_STATS_RATE_EST elements to netlink users, even if no estimator
is running.
# tc -s -d qdisc
qdisc pfifo_fast 0: dev eth0 root bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
Sent 112833764978 bytes 1495081739 pkt (dropped 0, overlimits 0 requeues 0)
rate 0bit 0pps backlog 0b 0p requeues 0
User has no way to tell if the "rate 0bit 0pps" is a real estimation, or a fake
one (because no estimator is active)
After this patch, tc command output is :
$ tc -s -d qdisc
qdisc pfifo_fast 0: dev eth0 root bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
Sent 561075 bytes 1196 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
We add a parameter to gnet_stats_copy_rate_est() function so that
it can use gen_estimator_active(bstats, r), as suggested by Jarek.
This parameter can be NULL if check is not necessary, (htb for
example has a mandatory rate estimator)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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The class argument to the ->graft(), ->leaf(), ->dump(), ->dump_stats() all
originate from either ->get() or ->walk() and are always valid.
Remove unnecessary checks.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In 5e140dfc1fe87eae27846f193086724806b33c7d "net: reorder struct Qdisc
for better SMP performance" the definition of struct gnet_stats_basic
changed incompatibly, as copies of this struct are shipped to
userland via netlink.
Restoring old behavior is not welcome, for performance reason.
Fix is to use a private structure for kernel, and
teach gnet_stats_copy_basic() to convert from kernel to user land,
using legacy structure (struct gnet_stats_basic)
Based on a report and initial patch from Michael Spang.
Reported-by: Michael Spang <mspang@csclub.uwaterloo.ca>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Use PSCHED_SHIFT constant instead of '10' in PSCHED_US2NS() and
PSCHED_NS2US() macros to enable changing this value later.
Additionally use PSCHED_SHIFT in sch_hfsc SM_SHIFT and ISM_SHIFT
definitions. This part of the patch is based on feedback from
Patrick McHardy <kaber@trash.net>.
Reported-by: Antonio Almeida <vexwek@gmail.com>
Tested-by: Antonio Almeida <vexwek@gmail.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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While looking for a possible reason of bugzilla report on HTB oops:
http://bugzilla.kernel.org/show_bug.cgi?id=12858
I found the code in htb_delete calling htb_destroy_class on zero
refcount is very misleading: it can suggest this is a common path, and
destroy is called under sch_tree_lock. Actually, this can never happen
like this because before deletion cops->get() is done, and after
delete a class is still used by tclass_notify. The class destroy is
always called from cops->put(), so without sch_tree_lock.
This doesn't mean much now (since 2.6.27) because all vulnerable calls
were moved from htb_destroy_class to htb_delete, but there was a bug
in older kernels. The same change is done for other classful scheds,
which, it seems, didn't have similar locking problems here.
Reported-by: m0sia <m0sia@m0sia.ru>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Patrick McHardy <kaber@trash.net> suggested:
> How about making this flag and the warning message (in a out-of-line
> function) globally available? Other qdiscs (f.i. HFSC) can't deal with
> inner non-work-conserving qdiscs as well.
This patch uses qdisc->flags field of "suspected" child qdisc.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The functions gen_new_estimator and gen_replace_estimator can return
errors, but they were being ignored.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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this warning:
net/sched/sch_hfsc.c: In function ‘hfsc_enqueue’:
net/sched/sch_hfsc.c:1577: warning: ‘err’ may be used uninitialized in this function
triggers because GCC does not recognize the (correct) error flow
between hfsc_classify(), 'cl' and 'err'.
Annotate it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The use of xchg() hasn't been necessary since 2.2.something when proper
locking was added to packet schedulers.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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After implementing qdisc->ops->peek() and changing sch_netem into
classless qdisc there are no more qdisc->ops->requeue() users. This
patch removes this method with its wrappers (qdisc_requeue()), and
also unused qdisc->requeue structure. There are a few minor fixes of
warnings (htb_enqueue()) and comments btw.
The idea to kill ->requeue() and a similar patch were first developed
by David S. Miller.
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch adds qdisc_peek_dequeued() wrapper to emulate peek method
with qdisc->dequeue() and storing "peeked" skb in qdisc->gso_skb until
dequeuing. This is mainly for compatibility reasons not to break some
strange configs because peeking is expected for non-work-conserving
parent qdiscs to query work-conserving child qdiscs.
This implementation requires using qdisc_dequeue_peeked() wrapper
instead of directly calling qdisc->dequeue() for all qdiscs ever
querried with qdisc->ops->peek() or qdisc_peek_dequeued().
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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