From: Lorenzo Bianconi <lorenzo@kernel.org>
To: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net,
lorenzo.bianconi@redhat.com, brouer@redhat.com,
echaudro@redhat.com, sameehj@amazon.com, kuba@kernel.org,
john.fastabend@gmail.com, daniel@iogearbox.net, ast@kernel.org,
shayagr@amazon.com
Subject: Re: [PATCH v2 net-next 7/9] bpf: helpers: add multibuffer support
Date: Fri, 4 Sep 2020 11:47:59 +0200 [thread overview]
Message-ID: <20200904094759.GG2884@lore-desk> (raw)
In-Reply-To: <20200903212409.GA14273@ranger.igk.intel.com>
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> On Thu, Sep 03, 2020 at 10:58:51PM +0200, Lorenzo Bianconi wrote:
> > From: Sameeh Jubran <sameehj@amazon.com>
> >
> > The implementation is based on this [0] draft by Jesper D. Brouer.
> >
> > Provided two new helpers:
> >
> > * bpf_xdp_get_frag_count()
> > * bpf_xdp_get_frags_total_size()
> >
> > [0] xdp mb design - https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org
> > Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> > include/uapi/linux/bpf.h | 14 ++++++++++++
> > net/core/filter.c | 39 ++++++++++++++++++++++++++++++++++
> > tools/include/uapi/linux/bpf.h | 14 ++++++++++++
> > 3 files changed, 67 insertions(+)
> >
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index c4a6d245619c..53db75095306 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -3590,6 +3590,18 @@ union bpf_attr {
> > *
> > * Return
> > * 0 on success, or a negative error in case of failure.
[...]
> > +
>
> I only quickly jumped through series and IMHO this helper should be
> rewritten/optimized in a way that we bail out as early as possible if
> !xdp->mb as the rest of the code on that condition will do nothing and i'm
> not sure if compiler would optimize it.
>
>
> struct skb_shared_info *sinfo;
> int nfrags, i;
> int size = 0;
>
> if (!xdp->mb)
> return 0;
>
> sinfo = xdp_get_shared_info_from_buff(xdp);
>
> nfrags = min(sinfo->nr_frags, MAX_SKB_FRAGS);
>
> for (i = 0; i < nfrags; i++)
> size += skb_frag_size(&sinfo->frags[i]);
>
> return size;
>
> Thoughts?
I agree.
Regards,
Lorenzo
>
>
> > + return size;
> > +}
> > +
> > +const struct bpf_func_proto bpf_xdp_get_frags_total_size_proto = {
> > + .func = bpf_xdp_get_frags_total_size,
> > + .gpl_only = false,
> > + .ret_type = RET_INTEGER,
> > + .arg1_type = ARG_PTR_TO_CTX,
> > +};
> > +
> > BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset)
> > {
> > void *data_hard_end = xdp_data_hard_end(xdp); /* use xdp->frame_sz */
> > @@ -6889,6 +6924,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > return &bpf_xdp_adjust_tail_proto;
> > case BPF_FUNC_xdp_adjust_mb_header:
> > return &bpf_xdp_adjust_mb_header_proto;
> > + case BPF_FUNC_xdp_get_frag_count:
> > + return &bpf_xdp_get_frag_count_proto;
> > + case BPF_FUNC_xdp_get_frags_total_size:
> > + return &bpf_xdp_get_frags_total_size_proto;
> > case BPF_FUNC_fib_lookup:
> > return &bpf_xdp_fib_lookup_proto;
> > #ifdef CONFIG_INET
> > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> > index 392d52a2ecef..dd4669096cbb 100644
> > --- a/tools/include/uapi/linux/bpf.h
> > +++ b/tools/include/uapi/linux/bpf.h
> > @@ -3591,6 +3591,18 @@ union bpf_attr {
> > *
> > * Return
> > * 0 on success, or a negative error in case of failure.
> > + *
> > + * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md)
> > + * Description
> > + * Get the total number of frags for a given packet.
> > + * Return
> > + * The number of frags
> > + *
> > + * int bpf_xdp_get_frags_total_size(struct xdp_buff *xdp_md)
> > + * Description
> > + * Get the total size of frags for a given packet.
> > + * Return
> > + * The total size of frags for a given packet.
> > */
> > #define __BPF_FUNC_MAPPER(FN) \
> > FN(unspec), \
> > @@ -3743,6 +3755,8 @@ union bpf_attr {
> > FN(d_path), \
> > FN(copy_from_user), \
> > FN(xdp_adjust_mb_header), \
> > + FN(xdp_get_frag_count), \
> > + FN(xdp_get_frags_total_size), \
> > /* */
> >
> > /* integer value in 'imm' field of BPF_CALL instruction selects which helper
> > --
> > 2.26.2
> >
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next prev parent reply other threads:[~2020-09-04 9:48 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 20:58 [PATCH v2 net-next 0/9] mvneta: introduce XDP multi-buffer support Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 1/9] xdp: introduce mb in xdp_buff/xdp_frame Lorenzo Bianconi
2020-09-04 1:07 ` Alexei Starovoitov
2020-09-04 7:19 ` Jesper Dangaard Brouer
2020-09-04 15:15 ` David Ahern
2020-09-04 15:59 ` Jesper Dangaard Brouer
2020-09-04 16:30 ` David Ahern
2020-09-07 18:02 ` Jesper Dangaard Brouer
2020-09-08 1:22 ` David Ahern
2020-09-03 20:58 ` [PATCH v2 net-next 2/9] xdp: initialize xdp_buff mb bit to 0 in all XDP drivers Lorenzo Bianconi
2020-09-04 7:35 ` Jesper Dangaard Brouer
2020-09-04 7:54 ` Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 3/9] net: mvneta: update mb bit before passing the xdp buffer to eBPF layer Lorenzo Bianconi
2020-09-06 7:33 ` Shay Agroskin
2020-09-06 9:05 ` Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 4/9] xdp: add multi-buff support to xdp_return_{buff/frame} Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 5/9] net: mvneta: add multi buffer support to XDP_TX Lorenzo Bianconi
2020-09-06 7:20 ` Shay Agroskin
2020-09-06 8:43 ` Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 6/9] bpf: helpers: add bpf_xdp_adjust_mb_header helper Lorenzo Bianconi
2020-09-04 1:09 ` Alexei Starovoitov
2020-09-04 8:07 ` Lorenzo Bianconi
2020-09-04 1:13 ` Alexei Starovoitov
2020-09-04 7:50 ` Lorenzo Bianconi
2020-09-04 13:52 ` Jesper Dangaard Brouer
2020-09-04 14:27 ` Lorenzo Bianconi
2020-09-04 6:47 ` John Fastabend
2020-09-04 9:45 ` Lorenzo Bianconi
2020-09-04 15:23 ` John Fastabend
2020-09-06 13:36 ` Lorenzo Bianconi
2020-09-08 19:57 ` John Fastabend
2020-09-08 21:31 ` Lorenzo Bianconi
2020-09-09 20:51 ` Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 7/9] bpf: helpers: add multibuffer support Lorenzo Bianconi
2020-09-03 21:24 ` Maciej Fijalkowski
2020-09-04 9:47 ` Lorenzo Bianconi [this message]
2020-09-03 20:58 ` [PATCH v2 net-next 8/9] samples/bpf: add bpf program that uses xdp mb helpers Lorenzo Bianconi
2020-09-03 20:58 ` [PATCH v2 net-next 9/9] net: mvneta: enable jumbo frames for XDP Lorenzo Bianconi
2020-09-04 1:08 ` [PATCH v2 net-next 0/9] mvneta: introduce XDP multi-buffer support Alexei Starovoitov
2020-09-04 7:40 ` Lorenzo Bianconi
2020-09-04 5:41 ` John Fastabend
2020-09-04 7:39 ` Lorenzo Bianconi
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