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Groups > linux.kernel > #1266948
| From | Z Lim <zlim.lnx@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction |
| Date | 2015-11-11 04:00 +0100 |
| Message-ID | <qttNE-5dn-7@gated-at.bofh.it> (permalink) |
| References | <qtqd4-36K-7@gated-at.bofh.it> <qtqd4-36K-5@gated-at.bofh.it> <qtr97-3J0-1@gated-at.bofh.it> <qtrsu-3Qd-3@gated-at.bofh.it> <qtrLP-3YD-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Yang, On Tue, Nov 10, 2015 at 4:42 PM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote: > On Tue, Nov 10, 2015 at 04:26:02PM -0800, Shi, Yang wrote: >> 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: aarch64 supports atomic add in ARMv8.1. For ARMv8(.0), please consider using LDXR/STXR 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 think doc is clear enough, but it can always be improved. Pls suggest a patch. > It's quite hard to write a test for atomicity in test_bpf framework, so > code review is the key. Eric, thanks for catching it! > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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[PATCH 2/2] arm64: bpf: add BPF XADD instruction Yang Shi <yang.shi@linaro.org> - 2015-11-11 00:10 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Eric Dumazet <eric.dumazet@gmail.com> - 2015-11-11 01:10 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction "Shi, Yang" <yang.shi@linaro.org> - 2015-11-11 01:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-11-11 01:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Z Lim <zlim.lnx@gmail.com> - 2015-11-11 04:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Arnd Bergmann <arnd@arndb.de> - 2015-11-11 10:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Will Deacon <will.deacon@arm.com> - 2015-11-11 11:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Daniel Borkmann <daniel@iogearbox.net> - 2015-11-11 11:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Will Deacon <will.deacon@arm.com> - 2015-11-11 13:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Daniel Borkmann <daniel@iogearbox.net> - 2015-11-11 13:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Will Deacon <will.deacon@arm.com> - 2015-11-11 13:40 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 14:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Daniel Borkmann <daniel@iogearbox.net> - 2015-11-11 17:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Will Deacon <will.deacon@arm.com> - 2015-11-11 17:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-11-11 18:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction David Miller <davem@davemloft.net> - 2015-11-11 18:40 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Will Deacon <will.deacon@arm.com> - 2015-11-11 18:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction David Miller <davem@davemloft.net> - 2015-11-11 20:10 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 19:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-11-11 19:20 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 19:40 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 19:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 19:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 20:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-11-11 21:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 23:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2015-11-12 00:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-12 10:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Daniel Borkmann <daniel@iogearbox.net> - 2015-11-11 20:00 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction David Miller <davem@davemloft.net> - 2015-11-11 20:10 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Peter Zijlstra <peterz@infradead.org> - 2015-11-11 20:30 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Daniel Borkmann <daniel@iogearbox.net> - 2015-11-11 20:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction Will Deacon <will.deacon@arm.com> - 2015-11-11 19:50 +0100
Re: [PATCH 2/2] arm64: bpf: add BPF XADD instruction David Miller <davem@davemloft.net> - 2015-11-11 20:10 +0100
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