From: peterz@infradead.org (Peter Zijlstra)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] arm64: bpf: add BPF XADD instruction
Date: Wed, 11 Nov 2015 23:21:35 +0100 [thread overview]
Message-ID: <20151111222135.GU17308@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20151111195558.GA4173@ast-mbp.thefacebook.com>
On Wed, Nov 11, 2015 at 11:55:59AM -0800, Alexei Starovoitov wrote:
> Therefore things like memory barriers, full set of atomics are not applicable
> in bpf world.
There are still plenty of wait-free constructs one can make using them.
Say a barrier/rendezvous construct for knowing when an event has
happened on all CPUs.
But if you really do not want any of that, I suppose that is a valid
choice.
Is even privileged (e)BPF not allowed things like this? I was thinking
the strict no loops stuff was for unpriv (e)BPF only.
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Miller <davem@davemloft.net>,
will.deacon@arm.com, daniel@iogearbox.net, arnd@arndb.de,
yang.shi@linaro.org, linaro-kernel@lists.linaro.org,
eric.dumazet@gmail.com, zlim.lnx@gmail.com, ast@kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
xi.wang@gmail.com, catalin.marinas@arm.com,
linux-arm-kernel@lists.infradead.org, yhs@plumgrid.com,
bblanco@plumgrid.com
Subject: Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction
Date: Wed, 11 Nov 2015 23:21:35 +0100 [thread overview]
Message-ID: <20151111222135.GU17308@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20151111195558.GA4173@ast-mbp.thefacebook.com>
On Wed, Nov 11, 2015 at 11:55:59AM -0800, Alexei Starovoitov wrote:
> Therefore things like memory barriers, full set of atomics are not applicable
> in bpf world.
There are still plenty of wait-free constructs one can make using them.
Say a barrier/rendezvous construct for knowing when an event has
happened on all CPUs.
But if you really do not want any of that, I suppose that is a valid
choice.
Is even privileged (e)BPF not allowed things like this? I was thinking
the strict no loops stuff was for unpriv (e)BPF only.
next prev parent reply other threads:[~2015-11-11 22:21 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
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 [this message]
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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