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From: "Björn Töpel" <bjorn.topel@intel.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Björn Töpel" <bjorn.topel@gmail.com>,
	ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Cc: magnus.karlsson@intel.com, jonathan.lemon@gmail.com,
	maximmi@nvidia.com, andrii@kernel.org, will@kernel.org
Subject: Re: [PATCH bpf-next 2/2] libbpf, xsk: add libbpf_smp_store_release libbpf_smp_load_acquire
Date: Tue, 2 Mar 2021 09:05:15 +0100	[thread overview]
Message-ID: <e052a22a-4b7b-fe38-06ad-2ad04c83dda7@intel.com> (raw)
In-Reply-To: <87k0qqx3be.fsf@toke.dk>

On 2021-03-01 17:10, Toke Høiland-Jørgensen wrote:
> Björn Töpel <bjorn.topel@gmail.com> writes:
> 
>> From: Björn Töpel <bjorn.topel@intel.com>
>>
>> Now that the AF_XDP rings have load-acquire/store-release semantics,
>> move libbpf to that as well.
>>
>> The library-internal libbpf_smp_{load_acquire,store_release} are only
>> valid for 32-bit words on ARM64.
>>
>> Also, remove the barriers that are no longer in use.
> 
> So what happens if an updated libbpf is paired with an older kernel (or
> vice versa)?
>

"This is fine." ;-) This was briefly discussed in [1], outlined by the
previous commit!

...even on POWER.


Björn

[1] https://lore.kernel.org/bpf/20200316184423.GA14143@willie-the-truck/


> -Toke
> 

  reply	other threads:[~2021-03-02 10:39 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-01 10:43 [PATCH bpf-next 0/2] load-acquire/store-release semantics for AF_XDP rings Björn Töpel
2021-03-01 10:43 ` [PATCH bpf-next 1/2] xsk: update rings for load-acquire/store-release semantics Björn Töpel
2021-03-01 16:08   ` Toke Høiland-Jørgensen
2021-03-02  8:04     ` Björn Töpel
2021-03-02 10:23       ` Toke Høiland-Jørgensen
2021-03-03  7:56         ` Björn Töpel
2021-03-01 10:43 ` [PATCH bpf-next 2/2] libbpf, xsk: add libbpf_smp_store_release libbpf_smp_load_acquire Björn Töpel
2021-03-01 16:10   ` Toke Høiland-Jørgensen
2021-03-02  8:05     ` Björn Töpel [this message]
2021-03-02  9:13       ` Daniel Borkmann
2021-03-02  9:16         ` Björn Töpel
2021-03-02  9:25           ` Daniel Borkmann
2021-03-03  8:08             ` Björn Töpel
2021-03-03 15:39         ` Will Deacon
2021-03-03 16:34           ` Björn Töpel
2021-03-03  4:38   ` Andrii Nakryiko
2021-03-03  7:14     ` Björn Töpel
2021-03-03  8:19       ` Björn Töpel

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