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From: "Björn Töpel" <bjorn.topel@intel.com>
To: "Eric Dumazet" <edumazet@google.com>,
	"Björn Töpel" <bjorn.topel@gmail.com>
Cc: netdev <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	magnus.karlsson@intel.com, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	maciej.fijalkowski@intel.com, "Samudrala,
	Sridhar" <sridhar.samudrala@intel.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	qi.z.zhang@intel.com, Jakub Kicinski <kuba@kernel.org>,
	Jonathan Lemon <jonathan.lemon@gmail.com>,
	maximmi@nvidia.com
Subject: Re: [PATCH bpf-next 2/9] net: add SO_BUSY_POLL_BUDGET socket option
Date: Thu, 12 Nov 2020 15:45:35 +0100	[thread overview]
Message-ID: <03a5a7d5-e5c9-5c61-8e8e-9393e8772d88@intel.com> (raw)
In-Reply-To: <CANn89i+Zumgn+phZEYPb9yCQRrJ7UYh1wY7SBio6ykg2noYz2w@mail.gmail.com>

On 2020-11-12 15:36, Eric Dumazet wrote:
> On Thu, Nov 12, 2020 at 12:41 PM Björn Töpel <bjorn.topel@gmail.com> wrote:
>>
>> From: Björn Töpel <bjorn.topel@intel.com>
>>
>> This option lets a user set a per socket NAPI budget for
>> busy-polling. If the options is not set, it will use the default of 8.
>>
>> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
>> ---
>>
> 
> ...
> 
>>   #else /* CONFIG_NET_RX_BUSY_POLL */
>>   static inline unsigned long net_busy_loop_on(void)
>> @@ -106,7 +108,8 @@ static inline void sk_busy_loop(struct sock *sk, int nonblock)
>>
>>          if (napi_id >= MIN_NAPI_ID)
>>                  napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
>> -                              READ_ONCE(sk->sk_prefer_busy_poll));
>> +                              READ_ONCE(sk->sk_prefer_busy_poll),
>> +                              sk->sk_busy_poll_budget ?: BUSY_POLL_BUDGET);
> 
> Please use :
> 
>         READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET
> 
> Because sk_busy_loop() is usually called without socket lock being held.
> 
> This will prevent yet another KCSAN report.
> 
>>   #endif
>>   }
>>
> 
> ...
> 
>> --- a/net/core/sock.c
>> +++ b/net/core/sock.c
>> @@ -1165,6 +1165,16 @@ int sock_setsockopt(struct socket *sock, int level, int optname,
>>                  else
>>                          sk->sk_prefer_busy_poll = valbool;
>>                  break;
>> +       case SO_BUSY_POLL_BUDGET:
>> +               if (val > sk->sk_busy_poll_budget && !capable(CAP_NET_ADMIN)) {
>> +                       ret = -EPERM;
>> +               } else {
>> +                       if (val < 0)
> 
>                 if (val < 0 || val > (u16)~0)
> 
>> +                               ret = -EINVAL;
>> +                       else
>> +                               sk->sk_busy_poll_budget = val;
> 
> 
>                                 WRITE_ONCE(sk->sk_busy_poll_budget, val);
>

Thanks for the review! I'll address it all.



  reply	other threads:[~2020-11-12 14:45 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12 11:40 [PATCH bpf-next 0/9] Introduce preferred busy-polling Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 1/9] net: introduce " Björn Töpel
2020-11-12 14:38   ` Eric Dumazet
2020-11-12 14:43     ` Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 2/9] net: add SO_BUSY_POLL_BUDGET socket option Björn Töpel
2020-11-12 14:36   ` Eric Dumazet
2020-11-12 14:45     ` Björn Töpel [this message]
2020-11-12 11:40 ` [PATCH bpf-next 3/9] xsk: add support for recvmsg() Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 4/9] xsk: check need wakeup flag in sendmsg() Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 5/9] xsk: add busy-poll support for {recv,send}msg() Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 6/9] xsk: propagate napi_id to XDP socket Rx path Björn Töpel
2020-11-15  4:48   ` Ilias Apalodimas
2020-11-12 11:40 ` [PATCH bpf-next 7/9] samples/bpf: use recvfrom() in xdpsock Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 8/9] samples/bpf: add busy-poll support to xdpsock Björn Töpel
2020-11-12 11:40 ` [PATCH bpf-next 9/9] samples/bpf: add option to set the busy-poll budget Björn Töpel

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