From: Jakub Kicinski <kuba@kernel.org>
To: Alexander Duyck <alexanderduyck@fb.com>
Cc: Eric Dumazet <edumazet@google.com>, Wei Wang <weiwan@google.com>,
"David S . Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Martin Zaharinov <micron10@gmail.com>
Subject: Re: [PATCH net] net: fix race between napi kthread mode and busy poll
Date: Wed, 24 Feb 2021 18:03:29 -0800 [thread overview]
Message-ID: <20210224180329.306b2207@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <BN8PR15MB27873FF52B109480173366B8BD9E9@BN8PR15MB2787.namprd15.prod.outlook.com>
On Thu, 25 Feb 2021 01:22:08 +0000 Alexander Duyck wrote:
> Yeah, that was the patch Wei had done earlier. Eric complained about the extra set_bit atomic operation in the threaded path. That is when I came up with the idea of just adding a bit to the busy poll logic so that the only extra cost in the threaded path was having to check 2 bits instead of 1.
Maybe we can set the bit only if the thread is running? When thread
comes out of schedule() it can be sure that it has an NAPI to service.
But when it enters napi_thread_wait() and before it hits schedule()
it must be careful to make sure the NAPI is still (or already in the
very first run after creation) owned by it.
next prev parent reply other threads:[~2021-02-25 2:04 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 23:41 [PATCH net] net: fix race between napi kthread mode and busy poll Wei Wang
2021-02-24 19:48 ` Jakub Kicinski
2021-02-24 20:37 ` Eric Dumazet
2021-02-24 21:30 ` Jakub Kicinski
2021-02-24 22:29 ` Wei Wang
2021-02-24 23:29 ` Jakub Kicinski
[not found] ` <CANn89i+xGsMpRfPwZK281jyfum_1fhTNFXq7Z8HOww9H1BHmiw@mail.gmail.com>
2021-02-24 23:52 ` Jakub Kicinski
2021-02-24 23:59 ` Eric Dumazet
2021-02-25 0:07 ` Jakub Kicinski
2021-02-25 0:11 ` Alexander Duyck
2021-02-25 0:16 ` Wei Wang
2021-02-25 0:32 ` Jakub Kicinski
2021-02-25 0:44 ` Wei Wang
2021-02-25 0:49 ` Jakub Kicinski
2021-02-25 1:06 ` Wei Wang
2021-02-25 1:40 ` Jakub Kicinski
2021-02-25 2:16 ` Wei Wang
2021-02-25 0:20 ` Jakub Kicinski
2021-02-25 1:22 ` Alexander Duyck
2021-02-25 2:03 ` Jakub Kicinski [this message]
2021-02-25 2:31 ` Wei Wang
2021-02-25 5:52 ` Martin Zaharinov
2021-02-25 8:21 ` Jakub Kicinski
2021-02-25 18:29 ` Wei Wang
2021-02-25 23:00 ` Jakub Kicinski
2021-02-26 0:16 ` Wei Wang
2021-02-26 1:18 ` Jakub Kicinski
2021-02-26 1:49 ` Wei Wang
2021-02-26 3:52 ` Alexander Duyck
2021-02-26 18:28 ` Wei Wang
2021-02-26 21:35 ` Jakub Kicinski
2021-02-26 22:24 ` Wei Wang
[not found] ` <CALidq=UWupwXMMYAMMF2GW4ifR0WQJos6VqXPuzQ0_seHGUHdA@mail.gmail.com>
2021-02-26 22:37 ` Wei Wang
2021-02-26 23:10 ` Jakub Kicinski
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