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From: Vlad Buslov <vladbu@mellanox•com>
To: Jakub Kicinski <jakub.kicinski@netronome•com>
Cc: Vlad Buslov <vladbu@mellanox•com>,
	"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
	"jhs@mojatatu•com" <jhs@mojatatu•com>,
	"xiyou.wangcong@gmail•com" <xiyou.wangcong@gmail•com>,
	"jiri@resnulli•us" <jiri@resnulli•us>,
	"davem@davemloft•net" <davem@davemloft•net>,
	"john.hurley@netronome•com" <john.hurley@netronome•com>
Subject: Re: [PATCH net-next] net: sched: flower: insert filter to ht before offloading it to hw
Date: Wed, 10 Apr 2019 16:02:17 +0000	[thread overview]
Message-ID: <vbfpnpt4znd.fsf@mellanox.com> (raw)
In-Reply-To: <20190410084830.378b37fa@cakuba.netronome.com>


On Wed 10 Apr 2019 at 18:48, Jakub Kicinski <jakub.kicinski@netronome•com> wrote:
> On Wed, 10 Apr 2019 14:53:53 +0000, Vlad Buslov wrote:
>> >> For my next patch set that unlocks the offloads API I implemented the
>> >> algorithm to track reoffload count for each tp that works like this:
>> >>
>> >> 1. struct tcf_proto is extended with reoffload_count counter that
>> >>    incremented each time reoffload is called on particular tp instance.
>> >>    Counter is protected by tp->lock.
>> >>
>> >> 2. struct cls_fl_filter is also extended with reoffload_count counter.
>> >>    Its value is set to current tp->reoffload_count when offloading the
>> >>    filter.
>> >>
>> >> 3. After offloading the filter, but before inserting it to idr,
>> >>    f->reoffload_count is compared with tp->reoffload_count. If values
>> >>    don't match, filter is deleted and -EAGAIN is returned. Cls API
>> >>    retries filter insertion on -EAGAIN.
>> >
>> > Sounds good for add.  Does this solve delete case as well?
>> >
>> >    CPU 0                       CPU 1
>> >
>> > __fl_delete
>> >   IDR remove
>> >                            cb unregister
>> >                              hw delete all flows  <- doesn't see the
>> >                                                      remove in progress
>> >
>> >   hw delete  <- doesn't see
>> >                 the removed cb
>>
>> Thanks for pointing that out! Looks like I need to move call to hw
>> delete in __fl_delete() function to be executed before idr removal.
>
> Ack, plus you need to do the same retry mechanism.  Save CB "count"/seq,
> hw delete, remove from IDR, if CB "count"/seq changed hw delete again.
> Right?

Actually, I intended to modify fl_reoffload() to ignore filters with
'deleted' flag set when adding, but I guess reusing 'reoffload_count' to
retry fl_hw_destroy_filter() would also work.

  reply	other threads:[~2019-04-10 16:02 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-05 17:56 [PATCH net-next] net: sched: flower: insert filter to ht before offloading it to hw Vlad Buslov
2019-04-06  5:59 ` Jiri Pirko
2019-04-08  2:34 ` David Miller
2019-04-08 22:26 ` Jakub Kicinski
2019-04-09  8:23   ` Vlad Buslov
2019-04-09 17:10     ` Jakub Kicinski
2019-04-10 14:53       ` Vlad Buslov
2019-04-10 15:48         ` Jakub Kicinski
2019-04-10 16:02           ` Vlad Buslov [this message]
2019-04-10 16:09             ` Jakub Kicinski
2019-04-10 16:26               ` Vlad Buslov
2019-04-10 17:00                 ` Jakub Kicinski
2019-04-16 14:20                   ` [RFC PATCH net-next] net: sched: flower: refactor reoffload for concurrent access Vlad Buslov
2019-04-16 21:49                     ` Jakub Kicinski
2019-04-17  7:29                       ` Vlad Buslov
2019-04-17 16:34                         ` Jakub Kicinski
2019-04-17 17:01                           ` Vlad Buslov
2019-04-18 16:33                           ` Vlad Buslov
2019-04-18 17:46                             ` Jakub Kicinski
2019-04-18 17:58                               ` Vlad Buslov
2019-04-18 18:02                                 ` Jakub Kicinski
2019-04-18 18:13                                   ` Vlad Buslov
2019-04-18 18:15                                     ` Jakub Kicinski
2019-04-11 11:13 ` [PATCH net-next] net: sched: flower: insert filter to ht before offloading it to hw Ido Schimmel
2019-04-11 11:28   ` Vlad Buslov

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