From: Jakub Kicinski <kuba@kernel.org>
To: "Björn Töpel" <bjorn.topel@gmail.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
"Björn Töpel" <bjorn.topel@intel.com>,
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 v3 01/10] net: introduce preferred busy-polling
Date: Mon, 23 Nov 2020 16:04:12 -0800 [thread overview]
Message-ID: <20201123160412.1bfb5161@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20201119083024.119566-2-bjorn.topel@gmail.com>
On Thu, 19 Nov 2020 09:30:15 +0100 Björn Töpel wrote:
> + /* 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;
> + }
Do we really need to go through napi_complete_done() here?
Isn't it sufficient to check:
if (napi_prefer_busy_poll(n) &&
hrtimer_active(&n->timer)) // not 100% sure this is the
// right helper for the check
If timer is scheduled it will fire and worst case sirq will kick back
in after timeout. napi_complete_done() should had been called by the
driver already to schedule the timer. If the driver doesn't call
napi_complete_done() we should not allow it to use busy_poll() anyway.
next prev parent reply other threads:[~2020-11-24 0:04 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 8:30 [PATCH bpf-next v3 00/10] Introduce preferred busy-polling Björn Töpel
2020-11-19 8:30 ` [PATCH bpf-next v3 01/10] net: introduce " Björn Töpel
2020-11-24 0:04 ` Jakub Kicinski [this message]
2020-11-24 7:58 ` Björn Töpel
2020-11-24 0:11 ` Jakub Kicinski
2020-11-24 8:47 ` Björn Töpel
2020-11-24 16:21 ` Jakub Kicinski
2020-11-19 8:30 ` [PATCH bpf-next v3 02/10] net: add SO_BUSY_POLL_BUDGET socket option Björn Töpel
2020-11-24 16:21 ` Jakub Kicinski
2020-11-19 8:30 ` [PATCH bpf-next v3 03/10] xsk: add support for recvmsg() Björn Töpel
2020-11-25 6:55 ` Magnus Karlsson
2020-11-19 8:30 ` [PATCH bpf-next v3 04/10] xsk: check need wakeup flag in sendmsg() Björn Töpel
2020-11-25 7:16 ` Magnus Karlsson
2020-11-19 8:30 ` [PATCH bpf-next v3 05/10] xsk: add busy-poll support for {recv,send}msg() Björn Töpel
2020-11-25 7:58 ` Magnus Karlsson
2020-11-19 8:30 ` [PATCH bpf-next v3 06/10] xsk: propagate napi_id to XDP socket Rx path Björn Töpel
2020-11-25 14:47 ` Magnus Karlsson
2020-11-25 21:14 ` Michael S. Tsirkin
2021-09-29 18:33 ` kernel test robot
2021-09-30 6:04 ` Magnus Karlsson
2021-10-02 2:07 ` [kbuild-all] " Philip Li
2021-11-05 20:17 ` kernel test robot
2020-11-19 8:30 ` [PATCH bpf-next v3 07/10] samples/bpf: use recvfrom() in xdpsock/rxdrop Björn Töpel
2020-11-25 7:59 ` Magnus Karlsson
2020-11-19 8:30 ` [PATCH bpf-next v3 08/10] samples/bpf: use recvfrom() in xdpsock/l2fwd Björn Töpel
2020-11-25 8:00 ` Magnus Karlsson
2020-11-19 8:30 ` [PATCH bpf-next v3 09/10] samples/bpf: add busy-poll support to xdpsock Björn Töpel
2020-11-25 8:19 ` Magnus Karlsson
2020-11-19 8:30 ` [PATCH bpf-next v3 10/10] samples/bpf: add option to set the busy-poll budget Björn Töpel
2020-11-25 8:23 ` Magnus Karlsson
2020-11-23 13:31 ` [PATCH bpf-next v3 00/10] Introduce preferred busy-polling Björn Töpel
2020-11-23 23:54 ` Jakub Kicinski
2020-11-24 0:14 ` Jakub Kicinski
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