* Re: [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine
@ 2021-08-29 13:27 kernel test robot
0 siblings, 0 replies; 3+ messages in thread
From: kernel test robot @ 2021-08-29 13:27 UTC (permalink / raw)
To: kbuild
[-- Attachment #1: Type: text/plain, Size: 6384 bytes --]
CC: kbuild-all(a)lists.01.org
In-Reply-To: <3d98cda6f49ef9ff34d2aec3d00924592b4739e3.1629473233.git.lorenzo@kernel.org>
References: <3d98cda6f49ef9ff34d2aec3d00924592b4739e3.1629473233.git.lorenzo@kernel.org>
TO: Lorenzo Bianconi <lorenzo@kernel.org>
TO: bpf(a)vger.kernel.org
TO: netdev(a)vger.kernel.org
CC: lorenzo.bianconi(a)redhat.com
CC: davem(a)davemloft.net
CC: kuba(a)kernel.org
CC: ast(a)kernel.org
CC: daniel(a)iogearbox.net
CC: shayagr(a)amazon.com
CC: john.fastabend(a)gmail.com
CC: dsahern(a)kernel.org
Hi Lorenzo,
I love your patch! Perhaps something to improve:
[auto build test WARNING on bpf-next/master]
url: https://github.com/0day-ci/linux/commits/Lorenzo-Bianconi/mvneta-introduce-XDP-multi-buffer-support/20210820-234736
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
:::::: branch date: 9 days ago
:::::: commit date: 9 days ago
config: i386-randconfig-m021-20210829 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
smatch warnings:
net/core/xdp.c:568 __xdp_build_skb_from_frame() error: uninitialized symbol 'nr_frags'.
net/core/xdp.c:569 __xdp_build_skb_from_frame() error: uninitialized symbol 'frag_size'.
net/core/xdp.c:569 __xdp_build_skb_from_frame() error: uninitialized symbol 'frag_tsize'.
vim +/nr_frags +568 net/core/xdp.c
65e6dcf73398dd Lorenzo Bianconi 2021-01-29 529
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 530 struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 531 struct sk_buff *skb,
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 532 struct net_device *dev)
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 533 {
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 534 unsigned int frag_size, frag_tsize;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 535 unsigned int headroom, frame_size;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 536 void *hard_start;
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 537 u8 nr_frags;
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 538
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 539 /* xdp multi-buff frame */
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 540 if (unlikely(xdp_frame_is_mb(xdpf))) {
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 541 struct skb_shared_info *sinfo;
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 542
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 543 sinfo = xdp_get_shared_info_from_frame(xdpf);
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 544 frag_tsize = sinfo->xdp_frags_tsize;
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 545 frag_size = sinfo->xdp_frags_size;
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 546 nr_frags = sinfo->nr_frags;
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 547 }
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 548
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 549 /* Part of headroom was reserved to xdpf */
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 550 headroom = sizeof(*xdpf) + xdpf->headroom;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 551
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 552 /* Memory size backing xdp_frame data already have reserved
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 553 * room for build_skb to place skb_shared_info in tailroom.
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 554 */
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 555 frame_size = xdpf->frame_sz;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 556
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 557 hard_start = xdpf->data - headroom;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 558 skb = build_skb_around(skb, hard_start, frame_size);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 559 if (unlikely(!skb))
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 560 return NULL;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 561
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 562 skb_reserve(skb, headroom);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 563 __skb_put(skb, xdpf->len);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 564 if (xdpf->metasize)
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 565 skb_metadata_set(skb, xdpf->metasize);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 566
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 567 if (unlikely(xdp_frame_is_mb(xdpf)))
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 @568 xdp_update_skb_shared_info(skb, nr_frags,
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 @569 frag_size, frag_tsize,
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 570 xdp_frame_is_frag_pfmemalloc(xdpf));
2f8c6ede2e6e56 Lorenzo Bianconi 2021-08-20 571
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 572 /* Essential SKB info: protocol and skb->dev */
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 573 skb->protocol = eth_type_trans(skb, dev);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 574
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 575 /* Optional SKB info, currently missing:
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 576 * - HW checksum info (skb->ip_summed)
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 577 * - HW RX hash (skb_set_hash)
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 578 * - RX ring dev queue index (skb_record_rx_queue)
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 579 */
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 580
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 581 /* Until page_pool get SKB return path, release DMA here */
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 582 xdp_release_frame(xdpf);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 583
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 584 /* Allow SKB to reuse area used by xdp_frame */
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 585 xdp_scrub_frame(xdpf);
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 586
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 587 return skb;
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 588 }
97a0e1ea7b41c2 Lorenzo Bianconi 2021-01-12 589 EXPORT_SYMBOL_GPL(__xdp_build_skb_from_frame);
89f479f0eccfc8 Lorenzo Bianconi 2021-01-12 590
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
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^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v12 bpf-next 00/18] mvneta: introduce XDP multi-buffer support
@ 2021-08-20 15:40 Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine Lorenzo Bianconi
0 siblings, 1 reply; 3+ messages in thread
From: Lorenzo Bianconi @ 2021-08-20 15:40 UTC (permalink / raw)
To: bpf, netdev
Cc: lorenzo.bianconi, davem, kuba, ast, daniel, shayagr,
john.fastabend, dsahern, brouer, echaudro, jasowang,
alexander.duyck, saeed, maciej.fijalkowski, magnus.karlsson,
tirthendu.sarkar, toke
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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This series introduce XDP multi-buffer support. The mvneta driver is
the first to support these new "non-linear" xdp_{buff,frame}. Reviewers
please focus on how these new types of xdp_{buff,frame} packets
traverse the different layers and the layout design. It is on purpose
that BPF-helpers are kept simple, as we don't want to expose the
internal layout to allow later changes.
The main idea for the new multi-buffer layout is to reuse the same
structure used for non-linear SKB. This rely on the "skb_shared_info"
struct at the end of the first buffer to link together subsequent
buffers. Keeping the layout compatible with SKBs is also done to ease
and speedup creating a SKB from an xdp_{buff,frame}.
Converting xdp_frame to SKB and deliver it to the network stack is shown
in patch 05/18 (e.g. cpumaps).
A multi-buffer bit (mb) has been introduced in the flags field of xdp_{buff,frame}
structure to notify the bpf/network layer if this is a xdp multi-buffer frame
(mb = 1) or not (mb = 0).
The mb bit will be set by a xdp multi-buffer capable driver only for
non-linear frames maintaining the capability to receive linear frames
without any extra cost since the skb_shared_info structure at the end
of the first buffer will be initialized only if mb is set.
Moreover the flags field in xdp_{buff,frame} will be reused even for
xdp rx csum offloading in future series.
Typical use cases for this series are:
- Jumbo-frames
- Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0])
- TSO/GRO
The two following ebpf helpers (and related selftests) has been introduced:
- bpf_xdp_adjust_data:
Move xdp_md->data and xdp_md->data_end pointers in subsequent fragments
according to the offset provided by the ebpf program. This helper can be
used to read/write values in frame payload.
- bpf_xdp_get_buff_len:
Return the total frame size (linear + paged parts)
bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into
account xdp multi-buff frames.
More info about the main idea behind this approach can be found here [1][2].
Changes since v11:
- add missing static to bpf_xdp_get_buff_len_proto structure
- fix bpf_xdp_adjust_data helper when offset is smaller than linear area length.
Changes since v10:
- move xdp->data to the requested payload offset instead of to the beginning of
the fragment in bpf_xdp_adjust_data()
Changes since v9:
- introduce bpf_xdp_adjust_data helper and related selftest
- add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info
- introduce xdp_update_skb_shared_info utility routine in ordere to not reset
frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb
- simplify bpf_xdp_copy routine
Changes since v8:
- add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff
- switch back to skb_shared_info implementation from previous xdp_shared_info
one
- avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance
regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance
penalties for regular codebase
- add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx
- add data_len field in skb_shared_info struct
- introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag
Changes since v7:
- rebase on top of bpf-next
- fix sparse warnings
- improve comments for frame_length in include/net/xdp.h
Changes since v6:
- the main difference respect to previous versions is the new approach proposed
by Eelco to pass full length of the packet to eBPF layer in XDP context
- reintroduce multi-buff support to eBPF kself-tests
- reintroduce multi-buff support to bpf_xdp_adjust_tail helper
- introduce multi-buffer support to bpf_xdp_copy helper
- rebase on top of bpf-next
Changes since v5:
- rebase on top of bpf-next
- initialize mb bit in xdp_init_buff() and drop per-driver initialization
- drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame()
- postpone introduction of frame_length field in XDP ctx to another series
- minor changes
Changes since v4:
- rebase ontop of bpf-next
- introduce xdp_shared_info to build xdp multi-buff instead of using the
skb_shared_info struct
- introduce frame_length in xdp ctx
- drop previous bpf helpers
- fix bpf_xdp_adjust_tail for xdp multi-buff
- introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail
- fix xdp_return_frame_bulk for xdp multi-buff
Changes since v3:
- rebase ontop of bpf-next
- add patch 10/13 to copy back paged data from a xdp multi-buff frame to
userspace buffer for xdp multi-buff selftests
Changes since v2:
- add throughput measurements
- drop bpf_xdp_adjust_mb_header bpf helper
- introduce selftest for xdp multibuffer
- addressed comments on bpf_xdp_get_frags_count
- introduce xdp multi-buff support to cpumaps
Changes since v1:
- Fix use-after-free in xdp_return_{buff/frame}
- Introduce bpf helpers
- Introduce xdp_mb sample program
- access skb_shared_info->nr_frags only on the last fragment
Changes since RFC:
- squash multi-buffer bit initialization in a single patch
- add mvneta non-linear XDP buff support for tx side
[0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy
[1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org
[2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section)
Eelco Chaudron (3):
bpf: add multi-buff support to the bpf_xdp_adjust_tail() API
bpf: add multi-buffer support to xdp copy helpers
bpf: update xdp_adjust_tail selftest to include multi-buffer
Lorenzo Bianconi (15):
net: skbuff: add size metadata to skb_shared_info for xdp
xdp: introduce flags field in xdp_buff/xdp_frame
net: mvneta: update mb bit before passing the xdp buffer to eBPF layer
net: mvneta: simplify mvneta_swbm_add_rx_fragment management
net: xdp: add xdp_update_skb_shared_info utility routine
net: marvell: rely on xdp_update_skb_shared_info utility routine
xdp: add multi-buff support to xdp_return_{buff/frame}
net: mvneta: add multi buffer support to XDP_TX
net: mvneta: enable jumbo frames for XDP
bpf: introduce bpf_xdp_get_buff_len helper
bpf: move user_size out of bpf_test_init
bpf: introduce multibuff support to bpf_prog_test_run_xdp()
bpf: test_run: add xdp_shared_info pointer in bpf_test_finish
signature
net: xdp: introduce bpf_xdp_adjust_data helper
bpf: add bpf_xdp_adjust_data selftest
drivers/net/ethernet/marvell/mvneta.c | 204 ++++++++++-------
include/linux/skbuff.h | 6 +-
include/net/xdp.h | 95 +++++++-
include/uapi/linux/bpf.h | 39 ++++
kernel/trace/bpf_trace.c | 3 +
net/bpf/test_run.c | 117 ++++++++--
net/core/filter.c | 213 +++++++++++++++++-
net/core/xdp.c | 76 ++++++-
tools/include/uapi/linux/bpf.h | 39 ++++
.../bpf/prog_tests/xdp_adjust_data.c | 55 +++++
.../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++
.../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++----
.../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +-
.../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++-
.../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +-
.../bpf/progs/test_xdp_update_frags.c | 41 ++++
16 files changed, 1036 insertions(+), 165 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_data.c
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread* [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine
2021-08-20 15:40 [PATCH v12 bpf-next 00/18] mvneta: introduce XDP multi-buffer support Lorenzo Bianconi
@ 2021-08-20 15:40 ` Lorenzo Bianconi
2021-08-31 23:38 ` John Fastabend
0 siblings, 1 reply; 3+ messages in thread
From: Lorenzo Bianconi @ 2021-08-20 15:40 UTC (permalink / raw)
To: bpf, netdev
Cc: lorenzo.bianconi, davem, kuba, ast, daniel, shayagr,
john.fastabend, dsahern, brouer, echaudro, jasowang,
alexander.duyck, saeed, maciej.fijalkowski, magnus.karlsson,
tirthendu.sarkar, toke
Introduce xdp_update_skb_shared_info routine to update frags array
metadata in skb_shared_info data structure converting to a skb from
a xdp_buff or xdp_frame.
According to the current skb_shared_info architecture in
xdp_frame/xdp_buff and to the xdp multi-buff support, there is
no need to run skb_add_rx_frag() and reset frags array converting the buffer
to a skb since the frag array will be in the same position for xdp_buff/xdp_frame
and for the skb, we just need to update memory metadata.
Introduce XDP_FLAGS_PF_MEMALLOC flag in xdp_buff_flags in order to mark
the xdp_buff or xdp_frame as under memory-pressure if pages of the frags array
are under memory pressure. Doing so we can avoid looping over all fragments in
xdp_update_skb_shared_info routine. The driver is expected to set the
flag constructing the xdp_buffer using xdp_buff_set_frag_pfmemalloc
utility routine.
Rely on xdp_update_skb_shared_info in __xdp_build_skb_from_frame routine
converting the multi-buff xdp_frame to a skb after performing a XDP_REDIRECT.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
include/net/xdp.h | 33 ++++++++++++++++++++++++++++++++-
net/core/xdp.c | 17 +++++++++++++++++
2 files changed, 49 insertions(+), 1 deletion(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index ed5ea784fd45..53cccdc9528c 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -67,7 +67,10 @@ struct xdp_txq_info {
};
enum xdp_buff_flags {
- XDP_FLAGS_MULTI_BUFF = BIT(0), /* non-linear xdp buff */
+ XDP_FLAGS_MULTI_BUFF = BIT(0), /* non-linear xdp buff */
+ XDP_FLAGS_FRAGS_PF_MEMALLOC = BIT(1), /* xdp multi-buff paged memory
+ * is under pressure
+ */
};
struct xdp_buff {
@@ -96,6 +99,16 @@ static __always_inline void xdp_buff_clear_mb(struct xdp_buff *xdp)
xdp->flags &= ~XDP_FLAGS_MULTI_BUFF;
}
+static __always_inline bool xdp_buff_is_frag_pfmemalloc(struct xdp_buff *xdp)
+{
+ return !!(xdp->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
+}
+
+static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp)
+{
+ xdp->flags |= XDP_FLAGS_FRAGS_PF_MEMALLOC;
+}
+
static __always_inline void
xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq)
{
@@ -151,6 +164,11 @@ static __always_inline bool xdp_frame_is_mb(struct xdp_frame *frame)
return !!(frame->flags & XDP_FLAGS_MULTI_BUFF);
}
+static __always_inline bool xdp_frame_is_frag_pfmemalloc(struct xdp_frame *frame)
+{
+ return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
+}
+
#define XDP_BULK_QUEUE_SIZE 16
struct xdp_frame_bulk {
int count;
@@ -186,6 +204,19 @@ static inline void xdp_scrub_frame(struct xdp_frame *frame)
frame->dev_rx = NULL;
}
+static inline void
+xdp_update_skb_shared_info(struct sk_buff *skb, u8 nr_frags,
+ unsigned int size, unsigned int truesize,
+ bool pfmemalloc)
+{
+ skb_shinfo(skb)->nr_frags = nr_frags;
+
+ skb->len += size;
+ skb->data_len += size;
+ skb->truesize += truesize;
+ skb->pfmemalloc |= pfmemalloc;
+}
+
/* Avoids inlining WARN macro in fast-path */
void xdp_warn(const char *msg, const char *func, const int line);
#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index cc92ccb38432..504be3ce3ca9 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -531,8 +531,20 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
struct sk_buff *skb,
struct net_device *dev)
{
+ unsigned int frag_size, frag_tsize;
unsigned int headroom, frame_size;
void *hard_start;
+ u8 nr_frags;
+
+ /* xdp multi-buff frame */
+ if (unlikely(xdp_frame_is_mb(xdpf))) {
+ struct skb_shared_info *sinfo;
+
+ sinfo = xdp_get_shared_info_from_frame(xdpf);
+ frag_tsize = sinfo->xdp_frags_tsize;
+ frag_size = sinfo->xdp_frags_size;
+ nr_frags = sinfo->nr_frags;
+ }
/* Part of headroom was reserved to xdpf */
headroom = sizeof(*xdpf) + xdpf->headroom;
@@ -552,6 +564,11 @@ struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
if (xdpf->metasize)
skb_metadata_set(skb, xdpf->metasize);
+ if (unlikely(xdp_frame_is_mb(xdpf)))
+ xdp_update_skb_shared_info(skb, nr_frags,
+ frag_size, frag_tsize,
+ xdp_frame_is_frag_pfmemalloc(xdpf));
+
/* Essential SKB info: protocol and skb->dev */
skb->protocol = eth_type_trans(skb, dev);
--
2.31.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* RE: [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine
2021-08-20 15:40 ` [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine Lorenzo Bianconi
@ 2021-08-31 23:38 ` John Fastabend
0 siblings, 0 replies; 3+ messages in thread
From: John Fastabend @ 2021-08-31 23:38 UTC (permalink / raw)
To: Lorenzo Bianconi, bpf, netdev
Cc: lorenzo.bianconi, davem, kuba, ast, daniel, shayagr,
john.fastabend, dsahern, brouer, echaudro, jasowang,
alexander.duyck, saeed, maciej.fijalkowski, magnus.karlsson,
tirthendu.sarkar, toke
Lorenzo Bianconi wrote:
> Introduce xdp_update_skb_shared_info routine to update frags array
> metadata in skb_shared_info data structure converting to a skb from
> a xdp_buff or xdp_frame.
> According to the current skb_shared_info architecture in
> xdp_frame/xdp_buff and to the xdp multi-buff support, there is
> no need to run skb_add_rx_frag() and reset frags array converting the buffer
> to a skb since the frag array will be in the same position for xdp_buff/xdp_frame
> and for the skb, we just need to update memory metadata.
> Introduce XDP_FLAGS_PF_MEMALLOC flag in xdp_buff_flags in order to mark
> the xdp_buff or xdp_frame as under memory-pressure if pages of the frags array
> are under memory pressure. Doing so we can avoid looping over all fragments in
> xdp_update_skb_shared_info routine. The driver is expected to set the
> flag constructing the xdp_buffer using xdp_buff_set_frag_pfmemalloc
> utility routine.
> Rely on xdp_update_skb_shared_info in __xdp_build_skb_from_frame routine
> converting the multi-buff xdp_frame to a skb after performing a XDP_REDIRECT.
>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
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2021-08-29 13:27 [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine kernel test robot
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2021-08-20 15:40 [PATCH v12 bpf-next 00/18] mvneta: introduce XDP multi-buffer support Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine Lorenzo Bianconi
2021-08-31 23:38 ` John Fastabend
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