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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Network Development <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next v2 0/8] Optimize BPF tail calls for direct jumps
Date: Fri, 22 Nov 2019 18:22:58 -0800	[thread overview]
Message-ID: <CAADnVQKpJDD-bG1GnhGwMKfk6rdshGmRY6UrfXtfkqD0V5Sb9A@mail.gmail.com> (raw)
In-Reply-To: <cover.1574452833.git.daniel@iogearbox.net>

On Fri, Nov 22, 2019 at 12:08 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> This gets rid of indirect jumps for BPF tail calls whenever possible.
> The series adds emission for *direct* jumps for tail call maps in order
> to avoid the retpoline overhead from a493a87f38cf ("bpf, x64: implement
> retpoline for tail call") for situations that allow for it, meaning,
> for known constant keys at verification time which are used as index
> into the tail call map. See patch 7/8 for more general details.
>
> Thanks!
>
> v1  -> v2:
>   - added more test cases
>   - u8 ip_stable -> bool (Andrii)
>   - removed bpf_map_poke_{un,}lock and simplified the code (Andrii)
>   - added break into prog_array_map_poke_untrack since there's just
>     one prog (Andrii)
>   - fixed typo: for for in commit msg (Andrii)
>   - reworked __bpf_arch_text_poke (Andrii)
>   - added subtests, and comment on tests themselves, NULL-NULL
>     transistion (Andrii)
>   - in constant map key tracking I've moved the map_poke_track callback
>     to once we've finished creating the poke tab as otherwise concurrent
>     access from tail call map would blow up (since we realloc the table)
> rfc -> v1:
>   - Applied Alexei's and Andrii's feeback from
>     https://lore.kernel.org/bpf/cover.1573779287.git.daniel@iogearbox.net/T/#t

Applied. Thanks!

      parent reply	other threads:[~2019-11-23  2:23 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-22 20:07 [PATCH bpf-next v2 0/8] Optimize BPF tail calls for direct jumps Daniel Borkmann
2019-11-22 20:07 ` [PATCH bpf-next v2 1/8] bpf, x86: generalize and extend bpf_arch_text_poke " Daniel Borkmann
2019-11-22 20:07 ` [PATCH bpf-next v2 2/8] bpf: move bpf_free_used_maps into sleepable section Daniel Borkmann
2019-11-22 20:07 ` [PATCH bpf-next v2 3/8] bpf: move owner type,jited info into array auxiliary data Daniel Borkmann
2019-11-22 20:07 ` [PATCH bpf-next v2 4/8] bpf: add initial poke descriptor table for jit images Daniel Borkmann
2019-11-22 20:07 ` [PATCH bpf-next v2 5/8] bpf: add poke dependency tracking for prog array maps Daniel Borkmann
2019-11-22 22:55   ` Andrii Nakryiko
2019-11-22 23:06     ` Daniel Borkmann
2019-11-22 23:10       ` Andrii Nakryiko
2019-11-22 20:07 ` [PATCH bpf-next v2 6/8] bpf: constant map key tracking for prog array pokes Daniel Borkmann
2019-11-22 22:57   ` Andrii Nakryiko
2019-11-23 10:39   ` Jakub Sitnicki
2019-11-22 20:08 ` [PATCH bpf-next v2 7/8] bpf, x86: emit patchable direct jump as tail call Daniel Borkmann
2019-11-22 23:09   ` Andrii Nakryiko
2019-11-22 23:25     ` Daniel Borkmann
2019-11-23  2:28       ` Alexei Starovoitov
2019-11-23  5:00         ` Andrii Nakryiko
2019-11-23  6:18           ` Alexei Starovoitov
2019-11-23  9:24             ` Daniel Borkmann
2019-11-22 20:08 ` [PATCH bpf-next v2 8/8] bpf, testing: add various tail call test cases Daniel Borkmann
2019-11-22 23:14   ` Andrii Nakryiko
2019-11-23  2:22 ` Alexei Starovoitov [this message]

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