kernel/linux.git/net/core/gen_stats.c, branch linux-4.13.y

net_sched: gen_estimator: complete rewrite of rate estimators

2016-12-05T20:21:59+00:00

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 Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2016-06-10T18:52:24+00:00

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

net: sched: fix missing doc annotations

2016-06-08T18:20:40+00:00

"make htmldocs" complains otherwise: .//net/core/gen_stats.c:168: warning: No description found for parameter 'running' .//include/linux/netdevice.h:1867: warning: No description found for parameter 'qdisc_running_key' Fixes: f9eb8aea2a1e ("net_sched: transform qdisc running bit into a seqcount") Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump") Signed-off-by: Eric Dumazet Reported-by: kbuild test robot Signed-off-by: David S. Miller

net_sched: add missing paddattr description

2016-06-08T18:17:39+00:00

"make htmldocs" complains otherwise: .//net/core/gen_stats.c:65: warning: No description found for parameter 'padattr' .//net/core/gen_stats.c:101: warning: No description found for parameter 'padattr' Fixes: 9854518ea04d ("sched: align nlattr properly when needed") Signed-off-by: Eric Dumazet Reported-by: kbuild test robot Acked-by: Nicolas Dichtel Signed-off-by: David S. Miller

net: sched: do not acquire qdisc spinlock in qdisc/class stats dump

2016-06-07T23:37:14+00:00

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 Cc: Cong Wang Cc: Jamal Hadi Salim Cc: John Fastabend Cc: Kevin Athey Cc: Xiaotian Pei Signed-off-by: David S. Miller

sched: align nlattr properly when needed

2016-04-26T16:00:49+00:00

Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller

gen_stats.c: Add description for cpu argument

2016-03-20T20:48:06+00:00

Function gnet_stats_copy_basic is missing the description of the cpu argument in the documentation. Adding it. Signed-off-by: Luis de Bethencourt Signed-off-by: David S. Miller

gen_stats.c: Duplicate xstats buffer for later use

2015-02-19T20:45:53+00:00

The gnet_stats_copy_app() function gets called, more often than not, with its second argument a pointer to an automatic variable in the caller's stack. Therefore, to avoid copying garbage afterwards when calling gnet_stats_finish_copy(), this data is better copied to a dynamically allocated memory that gets freed after use. [xiyou.wangcong@gmail.com: remove a useless kfree()] Signed-off-by: Ignacy Gawędzki Signed-off-by: Cong Wang Signed-off-by: David S. Miller

net_sched: fix unused variables in __gnet_stats_copy_basic_cpu()

2014-10-07T04:10:49+00:00

Probably not a big deal, but we'd better just use the one we get in retry loop. Fixes: commit 22e0f8b9322cb1a48b1357e8 ("net: sched: make bstats per cpu and estimator RCU safe") Reported-by: Joe Perches Cc: John Fastabend Signed-off-by: Cong Wang Signed-off-by: David S. Miller

net: sched: enable per cpu qstats

2014-09-30T05:02:26+00:00

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 Signed-off-by: David S. Miller