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author | Eric Dumazet <edumazet@google.com> | 2016-12-04 09:48:16 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2016-12-05 15:21:59 -0500 |
commit | 1c0d32fde5bdf1184bc274f864c09799278a1114 (patch) | |
tree | 47367d46dfc125e19294c3f5fa9a021520bd5660 /Documentation/sphinx | |
parent | a6e169312971219a34927e8fdece60046fafb8ba (diff) | |
download | linux-1c0d32fde5bdf1184bc274f864c09799278a1114.tar.gz |
net_sched: gen_estimator: complete rewrite of rate estimators
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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