From: yang.shi@linaro.org (Shi, Yang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] arm64: bpf: add BPF XADD instruction
Date: Tue, 10 Nov 2015 16:26:02 -0800 [thread overview]
Message-ID: <56428B1A.5090303@linaro.org> (raw)
In-Reply-To: <1447200535.17135.88.camel@edumazet-glaptop2.roam.corp.google.com>
On 11/10/2015 4:08 PM, Eric Dumazet wrote:
> On Tue, 2015-11-10 at 14:41 -0800, Yang Shi wrote:
>> aarch64 doesn't have native support for XADD instruction, implement it by
>> the below instruction sequence:
>>
>> Load (dst + off) to a register
>> Add src to it
>> Store it back to (dst + off)
>
> Not really what is needed ?
>
> See this BPF_XADD as an atomic_add() equivalent.
I see. Thanks. The documentation doesn't say too much about "exclusive"
add. If so it should need load-acquire/store-release.
I will rework it.
Yang
>
>
WARNING: multiple messages have this Message-ID (diff)
From: "Shi, Yang" <yang.shi@linaro.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: ast@kernel.org, daniel@iogearbox.net, catalin.marinas@arm.com,
will.deacon@arm.com, zlim.lnx@gmail.com, xi.wang@gmail.com,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linaro-kernel@lists.linaro.org
Subject: Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction
Date: Tue, 10 Nov 2015 16:26:02 -0800 [thread overview]
Message-ID: <56428B1A.5090303@linaro.org> (raw)
In-Reply-To: <1447200535.17135.88.camel@edumazet-glaptop2.roam.corp.google.com>
On 11/10/2015 4:08 PM, Eric Dumazet wrote:
> On Tue, 2015-11-10 at 14:41 -0800, Yang Shi wrote:
>> aarch64 doesn't have native support for XADD instruction, implement it by
>> the below instruction sequence:
>>
>> Load (dst + off) to a register
>> Add src to it
>> Store it back to (dst + off)
>
> Not really what is needed ?
>
> See this BPF_XADD as an atomic_add() equivalent.
I see. Thanks. The documentation doesn't say too much about "exclusive"
add. If so it should need load-acquire/store-release.
I will rework it.
Yang
>
>
next prev parent reply other threads:[~2015-11-11 0:26 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-10 22:41 [PATCH 0/2] arm64: bpf: add BPF_ST and BPF_XADD instructions support Yang Shi
2015-11-10 22:41 ` Yang Shi
2015-11-10 22:41 ` Yang Shi
2015-11-10 22:41 ` [PATCH 1/2] arm64: bpf: add 'store immediate' instruction Yang Shi
2015-11-10 22:41 ` Yang Shi
2015-11-11 2:45 ` Z Lim
2015-11-11 2:45 ` Z Lim
2015-11-11 12:12 ` Will Deacon
2015-11-11 12:12 ` Will Deacon
2015-11-11 12:39 ` Will Deacon
2015-11-11 12:39 ` Will Deacon
2015-11-12 19:33 ` Shi, Yang
2015-11-12 19:33 ` Shi, Yang
2015-11-13 3:45 ` Z Lim
2015-11-13 3:45 ` Z Lim
2015-11-23 19:34 ` Shi, Yang
2015-11-23 19:34 ` Shi, Yang
2015-11-10 22:41 ` [PATCH 2/2] arm64: bpf: add BPF XADD instruction Yang Shi
2015-11-10 22:41 ` Yang Shi
2015-11-11 0:08 ` Eric Dumazet
2015-11-11 0:08 ` Eric Dumazet
2015-11-11 0:26 ` Shi, Yang [this message]
2015-11-11 0:26 ` Shi, Yang
2015-11-11 0:42 ` Alexei Starovoitov
2015-11-11 0:42 ` Alexei Starovoitov
2015-11-11 2:52 ` Z Lim
2015-11-11 2:52 ` Z Lim
2015-11-11 8:49 ` Arnd Bergmann
2015-11-11 8:49 ` Arnd Bergmann
2015-11-11 10:24 ` Will Deacon
2015-11-11 10:24 ` Will Deacon
2015-11-11 10:42 ` Daniel Borkmann
2015-11-11 10:42 ` Daniel Borkmann
2015-11-11 11:58 ` Will Deacon
2015-11-11 11:58 ` Will Deacon
2015-11-11 12:21 ` Daniel Borkmann
2015-11-11 12:21 ` Daniel Borkmann
2015-11-11 12:38 ` Will Deacon
2015-11-11 12:38 ` Will Deacon
2015-11-11 12:58 ` Peter Zijlstra
2015-11-11 12:58 ` Peter Zijlstra
2015-11-11 15:52 ` Daniel Borkmann
2015-11-11 15:52 ` Daniel Borkmann
2015-11-11 16:23 ` Will Deacon
2015-11-11 16:23 ` Will Deacon
2015-11-11 17:27 ` Alexei Starovoitov
2015-11-11 17:27 ` Alexei Starovoitov
2015-11-11 17:35 ` David Miller
2015-11-11 17:35 ` David Miller
2015-11-11 17:44 ` Will Deacon
2015-11-11 17:44 ` Will Deacon
2015-11-11 19:01 ` David Miller
2015-11-11 19:01 ` David Miller
2015-11-11 17:57 ` Peter Zijlstra
2015-11-11 17:57 ` Peter Zijlstra
2015-11-11 18:11 ` Alexei Starovoitov
2015-11-11 18:11 ` Alexei Starovoitov
2015-11-11 18:31 ` Peter Zijlstra
2015-11-11 18:31 ` Peter Zijlstra
2015-11-11 18:41 ` Peter Zijlstra
2015-11-11 18:41 ` Peter Zijlstra
2015-11-11 18:44 ` Peter Zijlstra
2015-11-11 18:44 ` Peter Zijlstra
2015-11-11 18:54 ` Peter Zijlstra
2015-11-11 18:54 ` Peter Zijlstra
2015-11-11 19:55 ` Alexei Starovoitov
2015-11-11 19:55 ` Alexei Starovoitov
2015-11-11 22:21 ` Peter Zijlstra
2015-11-11 22:21 ` Peter Zijlstra
2015-11-11 23:40 ` Alexei Starovoitov
2015-11-11 23:40 ` Alexei Starovoitov
2015-11-11 23:40 ` Alexei Starovoitov
2015-11-12 8:57 ` Peter Zijlstra
2015-11-12 8:57 ` Peter Zijlstra
2015-11-11 18:50 ` Daniel Borkmann
2015-11-11 18:50 ` Daniel Borkmann
2015-11-11 19:04 ` David Miller
2015-11-11 19:04 ` David Miller
2015-11-11 19:23 ` Peter Zijlstra
2015-11-11 19:23 ` Peter Zijlstra
2015-11-11 19:41 ` Daniel Borkmann
2015-11-11 19:41 ` Daniel Borkmann
2015-11-11 18:46 ` Will Deacon
2015-11-11 18:46 ` Will Deacon
2015-11-11 19:01 ` David Miller
2015-11-11 19:01 ` David Miller
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