From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Song Liu <songliubraving@fb.com>
Cc: bpf <bpf@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <kernel-team@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>
Subject: Re: [PATCH v5 bpf-next 0/4] bpf: introduce bpf_get_task_stack()
Date: Wed, 1 Jul 2020 08:34:09 -0700 [thread overview]
Message-ID: <CAADnVQ+HFjn9+cXM9PRLEsopiEVfJ5vjVDBNrWUjZT8P8_kiVA@mail.gmail.com> (raw)
In-Reply-To: <20200630062846.664389-1-songliubraving@fb.com>
On Mon, Jun 29, 2020 at 11:28 PM Song Liu <songliubraving@fb.com> wrote:
>
> This set introduces a new helper bpf_get_task_stack(). The primary use case
> is to dump all /proc/*/stack to seq_file via bpf_iter__task.
>
> A few different approaches have been explored and compared:
>
> 1. A simple wrapper around stack_trace_save_tsk(), as v1 [1].
>
> This approach introduces new syntax, which is different to existing
> helper bpf_get_stack(). Therefore, this is not ideal.
>
> 2. Extend get_perf_callchain() to support "task" as argument.
>
> This approach reuses most of bpf_get_stack(). However, extending
> get_perf_callchain() requires non-trivial changes to architecture
> specific code. Which is error prone.
>
> 3. Current (v2) approach, leverages most of existing bpf_get_stack(), and
> uses stack_trace_save_tsk() to handle architecture specific logic.
>
> [1] https://lore.kernel.org/netdev/20200623070802.2310018-1-songliubraving@fb.com/
>
> Changes v4 => v5:
> 1. Rebase and work around git-am issue. (Alexei)
> 2. Update commit log for 4/4. (Yonghong)
Applied. Thanks
I've added /* */ tweak to BPF_FUNC_MAPPER, so we stop having
ongoing merge conflicts and preserve better 'git blame' for helpers.
prev parent reply other threads:[~2020-07-01 15:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-30 6:28 [PATCH v5 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Song Liu
2020-06-30 6:28 ` [PATCH v5 bpf-next 1/4] perf: expose get/put_callchain_entry() Song Liu
2020-06-30 6:28 ` [PATCH v5 bpf-next 2/4] bpf: introduce helper bpf_get_task_stack() Song Liu
2020-06-30 6:28 ` [PATCH v5 bpf-next 3/4] bpf: allow %pB in bpf_seq_printf() and bpf_trace_printk() Song Liu
2020-06-30 6:28 ` [PATCH v5 bpf-next 4/4] selftests/bpf: add bpf_iter test with bpf_get_task_stack() Song Liu
2020-07-01 15:34 ` Alexei Starovoitov [this message]
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