Re: [PATCH v7 bpf-next RESEND 1/2] bpf: Add bpf_read_branch_records() helper

From: "Daniel Xu" <dxu@dxuuu.xyz>
To: "Andrii Nakryiko" <andrii.nakryiko@gmail.com>
Cc: "bpf" <bpf@vger.kernel.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Andrii Nakryiko" <andriin@fb.com>,
	"open list" <linux-kernel@vger.kernel.org>,
	"Kernel Team" <kernel-team@fb.com>,
	"Peter Ziljstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>
Subject: Re: [PATCH v7 bpf-next RESEND 1/2] bpf: Add bpf_read_branch_records() helper
Date: Thu, 13 Feb 2020 22:34:56 -0800	[thread overview]
Message-ID: <C0LOF40A2NT4.1N6H8Y7LVZGFF@dlxu-fedora-R90QNFJV> (raw)
In-Reply-To: <CAEf4Bzam8ikJO7atrSS8s-rLJ0jHKNjahcuVEWFh7AAbGTaoGw@mail.gmail.com>

On Tue Feb 11, 2020 at 11:23 AM, Andrii Nakryiko wrote:
> On Mon, Feb 10, 2020 at 12:09 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
[...]
> > + * int bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
> > + *     Description
> > + *             For an eBPF program attached to a perf event, retrieve the
> > + *             branch records (struct perf_branch_entry) associated to *ctx*
> > + *             and store it in the buffer pointed by *buf* up to size
> > + *             *buf_size* bytes.
> > + *     Return
> > + *             On success, number of bytes written to *buf*. On error, a
> > + *             negative value.
> > + *
> > + *             The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
> > + *             instead return the number of bytes required to store all the
> > + *             branch entries. If this flag is set, *buf* may be NULL.
> > + *
> > + *             **-EINVAL** if arguments invalid or **buf_size** not a multiple
>
> 
> buf_size -> size

Whoops, thanks for catching.

[...]