From: Vlad Buslov <vladbu@mellanox.com>
To: netdev@vger.kernel.org
Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
davem@davemloft.net, Vlad Buslov <vladbu@mellanox.com>
Subject: [PATCH net-next 00/12] Refactor flower classifier to remove dependency on rtnl lock
Date: Thu, 14 Feb 2019 09:47:00 +0200 [thread overview]
Message-ID: <20190214074712.17846-1-vladbu@mellanox.com> (raw)
Currently, all netlink protocol handlers for updating rules, actions and
qdiscs are protected with single global rtnl lock which removes any
possibility for parallelism. This patch set is a third step to remove
rtnl lock dependency from TC rules update path.
Recently, new rtnl registration flag RTNL_FLAG_DOIT_UNLOCKED was added.
TC rule update handlers (RTM_NEWTFILTER, RTM_DELTFILTER, etc.) are
already registered with this flag and only take rtnl lock when qdisc or
classifier requires it. Classifiers can indicate that their ops
callbacks don't require caller to hold rtnl lock by setting the
TCF_PROTO_OPS_DOIT_UNLOCKED flag. The goal of this change is to refactor
flower classifier to support unlocked execution and register it with
unlocked flag.
This patch set implements following changes to make flower classifier
concurrency-safe:
- Implement reference counting for individual filters. Change fl_get to
take reference to filter. Implement tp->ops->put callback that was
introduced in cls API patch set to release reference to flower filter.
- Use tp->lock spinlock to protect internal classifier data structures
from concurrent modification.
- Handle concurrent tcf proto deletion by returning EAGAIN, which will
cause cls API to retry and create new proto instance or return error
to the user (depending on message type).
- Handle concurrent insertion of filter with same priority and handle by
returning EAGAIN, which will cause cls API to lookup filter again and
process it accordingly to netlink message flags.
- Extend flower mask with reference counting and protect masks list with
masks_lock spinlock.
- Prevent concurrent mask insertion by inserting temporary value to
masks hash table. This is necessary because mask initialization is a
sleeping operation and cannot be done while holding tp->lock.
Tcf hw offloads API is not changed by this patch set and still requires
caller to hold rtnl lock. Refactored flower classifier tracks rtnl lock
state by means of 'rtnl_held' flag provided by cls API and obtains the
lock before calling hw offloads.
With these changes flower classifier is safely registered with
TCF_PROTO_OPS_DOIT_UNLOCKED flag in last patch.
Github: [https://github.com/vbuslov/linux/tree/unlocked_flower_cong_1]
Vlad Buslov (12):
net: sched: flower: don't check for rtnl on head dereference
net: sched: flower: refactor fl_change
net: sched: flower: introduce reference counting for filters
net: sched: flower: track filter deletion with flag
net: sched: flower: add reference counter to flower mask
net: sched: flower: handle concurrent mask insertion
net: sched: flower: protect masks list with spinlock
net: sched: flower: handle concurrent filter insertion in fl_change
net: sched: flower: handle concurrent tcf proto deletion
net: sched: flower: protect flower classifier state with spinlock
net: sched: flower: track rtnl lock state
net: sched: flower: set unlocked flag for flower proto ops
net/sched/cls_flower.c | 424 +++++++++++++++++++++++++++++++++++++------------
1 file changed, 321 insertions(+), 103 deletions(-)
--
2.13.6
next reply other threads:[~2019-02-14 7:48 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 7:47 Vlad Buslov [this message]
2019-02-14 7:47 ` [PATCH net-next 01/12] net: sched: flower: don't check for rtnl on head dereference Vlad Buslov
2019-02-18 19:08 ` Cong Wang
2019-02-19 9:45 ` Vlad Buslov
2019-02-20 22:33 ` Cong Wang
2019-02-21 17:45 ` Vlad Buslov
2019-02-22 19:32 ` Cong Wang
2019-02-25 16:11 ` Vlad Buslov
2019-02-25 22:39 ` Cong Wang
2019-02-26 14:57 ` Vlad Buslov
2019-02-28 0:49 ` Cong Wang
2019-02-28 18:35 ` Vlad Buslov
2019-03-02 0:51 ` Cong Wang
2019-02-14 7:47 ` [PATCH net-next 02/12] net: sched: flower: refactor fl_change Vlad Buslov
2019-02-14 20:34 ` Stefano Brivio
2019-02-15 10:38 ` Vlad Buslov
2019-02-15 10:47 ` Stefano Brivio
2019-02-15 16:25 ` Vlad Buslov
2019-02-18 18:20 ` Stefano Brivio
2019-02-14 7:47 ` [PATCH net-next 03/12] net: sched: flower: introduce reference counting for filters Vlad Buslov
2019-02-14 20:34 ` Stefano Brivio
2019-02-15 11:22 ` Vlad Buslov
2019-02-15 12:32 ` Stefano Brivio
2019-02-14 7:47 ` [PATCH net-next 04/12] net: sched: flower: track filter deletion with flag Vlad Buslov
2019-02-14 20:49 ` Stefano Brivio
2019-02-15 15:54 ` Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 05/12] net: sched: flower: add reference counter to flower mask Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 06/12] net: sched: flower: handle concurrent mask insertion Vlad Buslov
2019-02-15 22:46 ` Stefano Brivio
2019-02-14 7:47 ` [PATCH net-next 07/12] net: sched: flower: protect masks list with spinlock Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 08/12] net: sched: flower: handle concurrent filter insertion in fl_change Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 09/12] net: sched: flower: handle concurrent tcf proto deletion Vlad Buslov
2019-02-18 20:47 ` Cong Wang
2019-02-19 14:08 ` Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 10/12] net: sched: flower: protect flower classifier state with spinlock Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 11/12] net: sched: flower: track rtnl lock state Vlad Buslov
2019-02-15 22:46 ` Stefano Brivio
2019-02-18 9:35 ` Vlad Buslov
2019-02-14 7:47 ` [PATCH net-next 12/12] net: sched: flower: set unlocked flag for flower proto ops Vlad Buslov
2019-02-18 19:27 ` Cong Wang
2019-02-19 10:15 ` Vlad Buslov
2019-02-20 22:36 ` Cong Wang
2019-02-18 19:15 ` [PATCH net-next 00/12] Refactor flower classifier to remove dependency on rtnl lock Cong Wang
2019-02-19 10:00 ` Vlad Buslov
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