From: "Björn Töpel" <bjorn.topel@intel.com>
To: "Jakub Kicinski" <kuba@kernel.org>,
"Björn Töpel" <bjorn.topel@gmail.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
magnus.karlsson@intel.com, ast@kernel.org, daniel@iogearbox.net,
maciej.fijalkowski@intel.com, sridhar.samudrala@intel.com,
jesse.brandeburg@intel.com, qi.z.zhang@intel.com,
edumazet@google.com, jonathan.lemon@gmail.com,
maximmi@nvidia.com
Subject: Re: [PATCH bpf-next v2 01/10] net: introduce preferred busy-polling
Date: Mon, 16 Nov 2020 17:19:17 +0100 [thread overview]
Message-ID: <2997d870-09d3-748f-0673-8e2baf7be3fa@intel.com> (raw)
In-Reply-To: <20201116080457.163bf83b@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On 2020-11-16 17:04, Jakub Kicinski wrote:
> On Mon, 16 Nov 2020 12:04:07 +0100 Björn Töpel wrote:
>> @@ -6771,6 +6806,19 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
>> if (likely(work < weight))
>> goto out_unlock;
>>
>> + /* The NAPI context has more processing work, but busy-polling
>> + * is preferred. Exit early.
>> + */
>> + if (napi_prefer_busy_poll(n)) {
>> + if (napi_complete_done(n, work)) {
>> + /* If timeout is not set, we need to make sure
>> + * that the NAPI is re-scheduled.
>> + */
>> + napi_schedule(n);
>> + }
>> + goto out_unlock;
>> + }
>
> Why is this before the disabled check?
>
This path is when the budget was exceeded (more work to be done). If the
prefer flag is set, the napi loop is exited prematurely. We check the
return value for napi_complete_done, to make sure that there is actually
a TO value set.
Uhm, maybe I not following what you mean by the "disabled check".
Björn
>> /* Drivers must not modify the NAPI state if they
>> * consume the entire weight. In such cases this code
>> * still "owns" the NAPI instance and therefore can
next prev parent reply other threads:[~2020-11-16 16:19 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-16 11:04 [PATCH bpf-next v2 00/10] Introduce preferred busy-polling Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 01/10] net: introduce " Björn Töpel
2020-11-16 16:04 ` Jakub Kicinski
2020-11-16 16:19 ` Björn Töpel [this message]
2020-11-16 17:28 ` Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 02/10] net: add SO_BUSY_POLL_BUDGET socket option Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 03/10] xsk: add support for recvmsg() Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 04/10] xsk: check need wakeup flag in sendmsg() Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 05/10] xsk: add busy-poll support for {recv,send}msg() Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 06/10] xsk: propagate napi_id to XDP socket Rx path Björn Töpel
2020-11-16 11:19 ` Tariq Toukan
2020-11-16 11:55 ` Michael S. Tsirkin
2020-11-16 12:01 ` Björn Töpel
2020-11-16 12:42 ` Michael S. Tsirkin
2020-11-16 13:24 ` Björn Töpel
2020-11-16 13:55 ` Michael S. Tsirkin
2020-11-16 17:40 ` Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 07/10] samples/bpf: use recvfrom() in xdpsock/rxdrop Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 08/10] samples/bpf: use recvfrom() in xdpsock/l2fwd Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 09/10] samples/bpf: add busy-poll support to xdpsock Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 10/10] samples/bpf: add option to set the busy-poll budget Björn Töpel
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