From: Jakub Kicinski <kuba@kernel.org>
To: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>, <davem@davemloft.net>,
<pabeni@redhat.com>, <edumazet@google.com>,
<netdev@vger.kernel.org>, <magnus.karlsson@intel.com>,
<aleksander.lobakin@intel.com>, <ast@kernel.org>,
<daniel@iogearbox.net>, <hawk@kernel.org>,
<john.fastabend@gmail.com>, <bpf@vger.kernel.org>,
Shannon Nelson <shannon.nelson@amd.com>,
Chandan Kumar Rout <chandanx.rout@intel.com>
Subject: Re: [PATCH net 6/8] ice: improve updating ice_{t, r}x_ring::xsk_pool
Date: Wed, 24 Jul 2024 07:57:42 -0700 [thread overview]
Message-ID: <20240724075742.0e70de49@kernel.org> (raw)
In-Reply-To: <ZqBAw0AEkieW+y4b@boxer>
On Wed, 24 Jul 2024 01:46:11 +0200 Maciej Fijalkowski wrote:
> Goal of this commit was to prevent compiler from code reoder such as NAPI
> is launched before update of xsk_buff_pool pointer which is achieved with
> WRITE_ONCE()/synchronize_net() pair. Then per my understanding single
> READ_ONCE() within NAPI was sufficient, the one that makes the decision
> which Rx routine should be called (zc or standard one). Given that bh are
> disabled and updater respects RCU grace period IMHO pointer is valid for
> current NAPI cycle.
So if we are already in the af_xdp handler, and update patch sets pool
to NULL - the af_xdp handler will be fine with the pool becoming NULL?
I guess it may be fine, it's just quite odd to call the function called
_ONCE() multiple times..
next prev parent reply other threads:[~2024-07-24 14:57 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-08 22:14 [PATCH net 0/8][pull request] ice: fix AF_XDP ZC timeout and concurrency issues Tony Nguyen
2024-07-08 22:14 ` [PATCH net 1/8] ice: respect netif readiness in AF_XDP ZC related ndo's Tony Nguyen
2024-07-08 22:14 ` [PATCH net 2/8] ice: don't busy wait for Rx queue disable in ice_qp_dis() Tony Nguyen
2024-07-08 22:14 ` [PATCH net 3/8] ice: replace synchronize_rcu with synchronize_net Tony Nguyen
2024-07-08 22:14 ` [PATCH net 4/8] ice: modify error handling when setting XSK pool in ndo_bpf Tony Nguyen
2024-07-08 22:14 ` [PATCH net 5/8] ice: toggle netif_carrier when setting up XSK pool Tony Nguyen
2024-07-08 22:14 ` [PATCH net 6/8] ice: improve updating ice_{t, r}x_ring::xsk_pool Tony Nguyen
2024-07-10 1:45 ` Jakub Kicinski
2024-07-23 23:46 ` Maciej Fijalkowski
2024-07-24 14:57 ` Jakub Kicinski [this message]
2024-07-24 15:49 ` Maciej Fijalkowski
2024-07-25 13:38 ` Jakub Kicinski
2024-07-25 18:31 ` Maciej Fijalkowski
2024-07-25 23:07 ` Jakub Kicinski
2024-07-26 13:43 ` Maciej Fijalkowski
2024-07-26 14:37 ` Jakub Kicinski
2024-07-08 22:14 ` [PATCH net 7/8] ice: add missing WRITE_ONCE when clearing ice_rx_ring::xdp_prog Tony Nguyen
2024-07-08 22:14 ` [PATCH net 8/8] ice: xsk: fix txq interrupt mapping Tony Nguyen
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