From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Song Liu <songliubraving@fb.com>
Cc: Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@fb.com>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 2/3] libbpf: make global data internal arrays mmap()-able, if possible
Date: Fri, 8 Nov 2019 11:34:59 -0800 [thread overview]
Message-ID: <CAEf4Bzb6cGC_UcH+-WfZaj1i7nnZApTGp3wb0g11HehcURtm9A@mail.gmail.com> (raw)
In-Reply-To: <A5F17C12-EBB2-4588-863E-69EDE650DE43@fb.com>
On Thu, Nov 7, 2019 at 10:44 PM Song Liu <songliubraving@fb.com> wrote:
>
>
>
> > On Nov 7, 2019, at 8:20 PM, Andrii Nakryiko <andriin@fb.com> wrote:
> >
> > Add detection of BPF_F_MMAPABLE flag support for arrays and add it as an extra
> > flag to internal global data maps, if supported by kernel. This allows users
> > to memory-map global data and use it without BPF map operations, greatly
> > simplifying user experience.
> >
> > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
>
> Acked-by: Song Liu <songliubraving@fb.com>
>
> With nit below.
>
> > ---
> > tools/lib/bpf/libbpf.c | 31 +++++++++++++++++++++++++++++--
> > 1 file changed, 29 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index fde6cb3e5d41..73607a31a068 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -142,6 +142,8 @@ struct bpf_capabilities {
> > __u32 btf_func:1;
> > /* BTF_KIND_VAR and BTF_KIND_DATASEC support */
> > __u32 btf_datasec:1;
> > + /* BPF_F_MMAPABLE is supported for arrays */
> > + __u32 array_mmap:1;
> > };
> >
> > /*
> > @@ -855,8 +857,6 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
> > pr_warn("failed to alloc map name\n");
> > return -ENOMEM;
> > }
> > - pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n",
> > - map_name, map->sec_idx, map->sec_offset);
> >
> > def = &map->def;
> > def->type = BPF_MAP_TYPE_ARRAY;
> > @@ -864,6 +864,12 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
> > def->value_size = data->d_size;
> > def->max_entries = 1;
> > def->map_flags = type == LIBBPF_MAP_RODATA ? BPF_F_RDONLY_PROG : 0;
> > + if (obj->caps.array_mmap)
> > + def->map_flags |= BPF_F_MMAPABLE;
> > +
> > + pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %u.\n",
>
> nit: Better print flags as %x.
>
>
sure, will update
next prev parent reply other threads:[~2019-11-08 19:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-08 4:20 [PATCH bpf-next 0/3] Add support for memory-mapping BPF array maps Andrii Nakryiko
2019-11-08 4:20 ` [PATCH bpf-next 1/3] bpf: add mmap() support for BPF_MAP_TYPE_ARRAY Andrii Nakryiko
2019-11-08 6:39 ` Song Liu
2019-11-08 19:34 ` Andrii Nakryiko
2019-11-11 16:39 ` Song Liu
2019-11-08 4:20 ` [PATCH bpf-next 2/3] libbpf: make global data internal arrays mmap()-able, if possible Andrii Nakryiko
2019-11-08 6:44 ` Song Liu
2019-11-08 19:34 ` Andrii Nakryiko [this message]
2019-11-08 4:20 ` [PATCH bpf-next 3/3] selftests/bpf: add BPF_TYPE_MAP_ARRAY mmap() tests Andrii Nakryiko
2019-11-08 6:49 ` Song Liu
2019-11-08 22:08 ` [PATCH bpf-next 0/3] Add support for memory-mapping BPF array maps Stanislav Fomichev
2019-11-08 23:19 ` Andrii Nakryiko
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