<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/xdp, branch v5.15</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2021-06-29T22:45:27+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2021-06-29T22:45:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b6df00789e2831fff7a2c65aa7164b2a4dcbe599'/>
<id>b6df00789e2831fff7a2c65aa7164b2a4dcbe599</id>
<content type='text'>
Trivial conflict in net/netfilter/nf_tables_api.c.

Duplicate fix in tools/testing/selftests/net/devlink_port_split.py
- take the net-next version.

skmsg, and L4 bpf - keep the bpf code but remove the flags
and err params.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Trivial conflict in net/netfilter/nf_tables_api.c.

Duplicate fix in tools/testing/selftests/net/devlink_port_split.py
- take the net-next version.

skmsg, and L4 bpf - keep the bpf code but remove the flags
and err params.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: sock: introduce sk_error_report</title>
<updated>2021-06-29T18:28:21+00:00</updated>
<author>
<name>Alexander Aring</name>
<email>aahringo@redhat.com</email>
</author>
<published>2021-06-27T22:48:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e3ae2365efc14269170a6326477e669332271ab3'/>
<id>e3ae2365efc14269170a6326477e669332271ab3</id>
<content type='text'>
This patch introduces a function wrapper to call the sk_error_report
callback. That will prepare to add additional handling whenever
sk_error_report is called, for example to trace socket errors.

Signed-off-by: Alexander Aring &lt;aahringo@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch introduces a function wrapper to call the sk_error_report
callback. That will prepare to add additional handling whenever
sk_error_report is called, for example to trace socket errors.

Signed-off-by: Alexander Aring &lt;aahringo@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>xdp: Add proper __rcu annotations to redirect map entries</title>
<updated>2021-06-24T17:41:15+00:00</updated>
<author>
<name>Toke Høiland-Jørgensen</name>
<email>toke@redhat.com</email>
</author>
<published>2021-06-24T16:05:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=782347b6bcad07ddb574422e01e22c92e05928c8'/>
<id>782347b6bcad07ddb574422e01e22c92e05928c8</id>
<content type='text'>
XDP_REDIRECT works by a three-step process: the bpf_redirect() and
bpf_redirect_map() helpers will lookup the target of the redirect and store
it (along with some other metadata) in a per-CPU struct bpf_redirect_info.
Next, when the program returns the XDP_REDIRECT return code, the driver
will call xdp_do_redirect() which will use the information thus stored to
actually enqueue the frame into a bulk queue structure (that differs
slightly by map type, but shares the same principle). Finally, before
exiting its NAPI poll loop, the driver will call xdp_do_flush(), which will
flush all the different bulk queues, thus completing the redirect.

Pointers to the map entries will be kept around for this whole sequence of
steps, protected by RCU. However, there is no top-level rcu_read_lock() in
the core code; instead drivers add their own rcu_read_lock() around the XDP
portions of the code, but somewhat inconsistently as Martin discovered[0].
However, things still work because everything happens inside a single NAPI
poll sequence, which means it's between a pair of calls to
local_bh_disable()/local_bh_enable(). So Paul suggested[1] that we could
document this intention by using rcu_dereference_check() with
rcu_read_lock_bh_held() as a second parameter, thus allowing sparse and
lockdep to verify that everything is done correctly.

This patch does just that: we add an __rcu annotation to the map entry
pointers and remove the various comments explaining the NAPI poll assurance
strewn through devmap.c in favour of a longer explanation in filter.c. The
goal is to have one coherent documentation of the entire flow, and rely on
the RCU annotations as a "standard" way of communicating the flow in the
map code (which can additionally be understood by sparse and lockdep).

The RCU annotation replacements result in a fairly straight-forward
replacement where READ_ONCE() becomes rcu_dereference_check(), WRITE_ONCE()
becomes rcu_assign_pointer() and xchg() and cmpxchg() gets wrapped in the
proper constructs to cast the pointer back and forth between __rcu and
__kernel address space (for the benefit of sparse). The one complication is
that xskmap has a few constructions where double-pointers are passed back
and forth; these simply all gain __rcu annotations, and only the final
reference/dereference to the inner-most pointer gets changed.

With this, everything can be run through sparse without eliciting
complaints, and lockdep can verify correctness even without the use of
rcu_read_lock() in the drivers. Subsequent patches will clean these up from
the drivers.

[0] https://lore.kernel.org/bpf/20210415173551.7ma4slcbqeyiba2r@kafai-mbp.dhcp.thefacebook.com/
[1] https://lore.kernel.org/bpf/20210419165837.GA975577@paulmck-ThinkPad-P17-Gen-1/

Signed-off-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Link: https://lore.kernel.org/bpf/20210624160609.292325-6-toke@redhat.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
XDP_REDIRECT works by a three-step process: the bpf_redirect() and
bpf_redirect_map() helpers will lookup the target of the redirect and store
it (along with some other metadata) in a per-CPU struct bpf_redirect_info.
Next, when the program returns the XDP_REDIRECT return code, the driver
will call xdp_do_redirect() which will use the information thus stored to
actually enqueue the frame into a bulk queue structure (that differs
slightly by map type, but shares the same principle). Finally, before
exiting its NAPI poll loop, the driver will call xdp_do_flush(), which will
flush all the different bulk queues, thus completing the redirect.

Pointers to the map entries will be kept around for this whole sequence of
steps, protected by RCU. However, there is no top-level rcu_read_lock() in
the core code; instead drivers add their own rcu_read_lock() around the XDP
portions of the code, but somewhat inconsistently as Martin discovered[0].
However, things still work because everything happens inside a single NAPI
poll sequence, which means it's between a pair of calls to
local_bh_disable()/local_bh_enable(). So Paul suggested[1] that we could
document this intention by using rcu_dereference_check() with
rcu_read_lock_bh_held() as a second parameter, thus allowing sparse and
lockdep to verify that everything is done correctly.

This patch does just that: we add an __rcu annotation to the map entry
pointers and remove the various comments explaining the NAPI poll assurance
strewn through devmap.c in favour of a longer explanation in filter.c. The
goal is to have one coherent documentation of the entire flow, and rely on
the RCU annotations as a "standard" way of communicating the flow in the
map code (which can additionally be understood by sparse and lockdep).

The RCU annotation replacements result in a fairly straight-forward
replacement where READ_ONCE() becomes rcu_dereference_check(), WRITE_ONCE()
becomes rcu_assign_pointer() and xchg() and cmpxchg() gets wrapped in the
proper constructs to cast the pointer back and forth between __rcu and
__kernel address space (for the benefit of sparse). The one complication is
that xskmap has a few constructions where double-pointers are passed back
and forth; these simply all gain __rcu annotations, and only the final
reference/dereference to the inner-most pointer gets changed.

With this, everything can be run through sparse without eliciting
complaints, and lockdep can verify correctness even without the use of
rcu_read_lock() in the drivers. Subsequent patches will clean these up from
the drivers.

[0] https://lore.kernel.org/bpf/20210415173551.7ma4slcbqeyiba2r@kafai-mbp.dhcp.thefacebook.com/
[1] https://lore.kernel.org/bpf/20210419165837.GA975577@paulmck-ThinkPad-P17-Gen-1/

Signed-off-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Link: https://lore.kernel.org/bpf/20210624160609.292325-6-toke@redhat.com
</pre>
</div>
</content>
</entry>
<entry>
<title>xsk: Fix broken Tx ring validation</title>
<updated>2021-06-18T14:59:20+00:00</updated>
<author>
<name>Magnus Karlsson</name>
<email>magnus.karlsson@intel.com</email>
</author>
<published>2021-06-18T07:58:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f654fae47e83e56b454fbbfd0af0a4f232e356d6'/>
<id>f654fae47e83e56b454fbbfd0af0a4f232e356d6</id>
<content type='text'>
Fix broken Tx ring validation for AF_XDP. The commit under the Fixes
tag, fixed an off-by-one error in the validation but introduced
another error. Descriptors are now let through even if they straddle a
chunk boundary which they are not allowed to do in aligned mode. Worse
is that they are let through even if they straddle the end of the umem
itself, tricking the kernel to read data outside the allowed umem
region which might or might not be mapped at all.

Fix this by reintroducing the old code, but subtract the length by one
to fix the off-by-one error that the original patch was
addressing. The test chunk != chunk_end makes sure packets do not
straddle chunk boundraries. Note that packets of zero length are
allowed in the interface, therefore the test if the length is
non-zero.

Fixes: ac31565c2193 ("xsk: Fix for xp_aligned_validate_desc() when len == chunk_size")
Signed-off-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Reviewed-by: Xuan Zhuo &lt;xuanzhuo@linux.alibaba.com&gt;
Acked-by: Björn Töpel &lt;bjorn@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20210618075805.14412-1-magnus.karlsson@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix broken Tx ring validation for AF_XDP. The commit under the Fixes
tag, fixed an off-by-one error in the validation but introduced
another error. Descriptors are now let through even if they straddle a
chunk boundary which they are not allowed to do in aligned mode. Worse
is that they are let through even if they straddle the end of the umem
itself, tricking the kernel to read data outside the allowed umem
region which might or might not be mapped at all.

Fix this by reintroducing the old code, but subtract the length by one
to fix the off-by-one error that the original patch was
addressing. The test chunk != chunk_end makes sure packets do not
straddle chunk boundraries. Note that packets of zero length are
allowed in the interface, therefore the test if the length is
non-zero.

Fixes: ac31565c2193 ("xsk: Fix for xp_aligned_validate_desc() when len == chunk_size")
Signed-off-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Reviewed-by: Xuan Zhuo &lt;xuanzhuo@linux.alibaba.com&gt;
Acked-by: Björn Töpel &lt;bjorn@kernel.org&gt;
Link: https://lore.kernel.org/bpf/20210618075805.14412-1-magnus.karlsson@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>xdp: Extend xdp_redirect_map with broadcast support</title>
<updated>2021-05-26T07:46:16+00:00</updated>
<author>
<name>Hangbin Liu</name>
<email>liuhangbin@gmail.com</email>
</author>
<published>2021-05-19T09:07:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e624d4ed4aa8cc3c69d1359b0aaea539203ed266'/>
<id>e624d4ed4aa8cc3c69d1359b0aaea539203ed266</id>
<content type='text'>
This patch adds two flags BPF_F_BROADCAST and BPF_F_EXCLUDE_INGRESS to
extend xdp_redirect_map for broadcast support.

With BPF_F_BROADCAST the packet will be broadcasted to all the interfaces
in the map. with BPF_F_EXCLUDE_INGRESS the ingress interface will be
excluded when do broadcasting.

When getting the devices in dev hash map via dev_map_hash_get_next_key(),
there is a possibility that we fall back to the first key when a device
was removed. This will duplicate packets on some interfaces. So just walk
the whole buckets to avoid this issue. For dev array map, we also walk the
whole map to find valid interfaces.

Function bpf_clear_redirect_map() was removed in
commit ee75aef23afe ("bpf, xdp: Restructure redirect actions").
Add it back as we need to use ri-&gt;map again.

With test topology:
  +-------------------+             +-------------------+
  | Host A (i40e 10G) |  ---------- | eno1(i40e 10G)    |
  +-------------------+             |                   |
                                    |   Host B          |
  +-------------------+             |                   |
  | Host C (i40e 10G) |  ---------- | eno2(i40e 10G)    |
  +-------------------+             |                   |
                                    |          +------+ |
                                    | veth0 -- | Peer | |
                                    | veth1 -- |      | |
                                    | veth2 -- |  NS  | |
                                    |          +------+ |
                                    +-------------------+

On Host A:
 # pktgen/pktgen_sample03_burst_single_flow.sh -i eno1 -d $dst_ip -m $dst_mac -s 64

On Host B(Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz, 128G Memory):
Use xdp_redirect_map and xdp_redirect_map_multi in samples/bpf for testing.
All the veth peers in the NS have a XDP_DROP program loaded. The
forward_map max_entries in xdp_redirect_map_multi is modify to 4.

Testing the performance impact on the regular xdp_redirect path with and
without patch (to check impact of additional check for broadcast mode):

5.12 rc4         | redirect_map        i40e-&gt;i40e      |    2.0M |  9.7M
5.12 rc4         | redirect_map        i40e-&gt;veth      |    1.7M | 11.8M
5.12 rc4 + patch | redirect_map        i40e-&gt;i40e      |    2.0M |  9.6M
5.12 rc4 + patch | redirect_map        i40e-&gt;veth      |    1.7M | 11.7M

Testing the performance when cloning packets with the redirect_map_multi
test, using a redirect map size of 4, filled with 1-3 devices:

5.12 rc4 + patch | redirect_map multi  i40e-&gt;veth (x1) |    1.7M | 11.4M
5.12 rc4 + patch | redirect_map multi  i40e-&gt;veth (x2) |    1.1M |  4.3M
5.12 rc4 + patch | redirect_map multi  i40e-&gt;veth (x3) |    0.8M |  2.6M

Signed-off-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210519090747.1655268-3-liuhangbin@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds two flags BPF_F_BROADCAST and BPF_F_EXCLUDE_INGRESS to
extend xdp_redirect_map for broadcast support.

With BPF_F_BROADCAST the packet will be broadcasted to all the interfaces
in the map. with BPF_F_EXCLUDE_INGRESS the ingress interface will be
excluded when do broadcasting.

When getting the devices in dev hash map via dev_map_hash_get_next_key(),
there is a possibility that we fall back to the first key when a device
was removed. This will duplicate packets on some interfaces. So just walk
the whole buckets to avoid this issue. For dev array map, we also walk the
whole map to find valid interfaces.

Function bpf_clear_redirect_map() was removed in
commit ee75aef23afe ("bpf, xdp: Restructure redirect actions").
Add it back as we need to use ri-&gt;map again.

With test topology:
  +-------------------+             +-------------------+
  | Host A (i40e 10G) |  ---------- | eno1(i40e 10G)    |
  +-------------------+             |                   |
                                    |   Host B          |
  +-------------------+             |                   |
  | Host C (i40e 10G) |  ---------- | eno2(i40e 10G)    |
  +-------------------+             |                   |
                                    |          +------+ |
                                    | veth0 -- | Peer | |
                                    | veth1 -- |      | |
                                    | veth2 -- |  NS  | |
                                    |          +------+ |
                                    +-------------------+

On Host A:
 # pktgen/pktgen_sample03_burst_single_flow.sh -i eno1 -d $dst_ip -m $dst_mac -s 64

On Host B(Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz, 128G Memory):
Use xdp_redirect_map and xdp_redirect_map_multi in samples/bpf for testing.
All the veth peers in the NS have a XDP_DROP program loaded. The
forward_map max_entries in xdp_redirect_map_multi is modify to 4.

Testing the performance impact on the regular xdp_redirect path with and
without patch (to check impact of additional check for broadcast mode):

5.12 rc4         | redirect_map        i40e-&gt;i40e      |    2.0M |  9.7M
5.12 rc4         | redirect_map        i40e-&gt;veth      |    1.7M | 11.8M
5.12 rc4 + patch | redirect_map        i40e-&gt;i40e      |    2.0M |  9.6M
5.12 rc4 + patch | redirect_map        i40e-&gt;veth      |    1.7M | 11.7M

Testing the performance when cloning packets with the redirect_map_multi
test, using a redirect map size of 4, filled with 1-3 devices:

5.12 rc4 + patch | redirect_map multi  i40e-&gt;veth (x1) |    1.7M | 11.4M
5.12 rc4 + patch | redirect_map multi  i40e-&gt;veth (x2) |    1.1M |  4.3M
5.12 rc4 + patch | redirect_map multi  i40e-&gt;veth (x3) |    0.8M |  2.6M

Signed-off-by: Hangbin Liu &lt;liuhangbin@gmail.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Acked-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210519090747.1655268-3-liuhangbin@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>xsk: Use kvcalloc to support large umems</title>
<updated>2021-05-25T11:11:50+00:00</updated>
<author>
<name>Magnus Karlsson</name>
<email>magnus.karlsson@intel.com</email>
</author>
<published>2021-05-21T08:33:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a720a2a0ad6cb6f769b6c7cbc3c54287a7d54ff8'/>
<id>a720a2a0ad6cb6f769b6c7cbc3c54287a7d54ff8</id>
<content type='text'>
Use kvcalloc() instead of kcalloc() to support large umems with, on my
server, one million pages or more in the umem.

Reported-by: Dan Siemon &lt;dan@coverfire.com&gt;
Signed-off-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Björn Töpel &lt;bjorn@kernel.org&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20210521083301.26921-1-magnus.karlsson@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Use kvcalloc() instead of kcalloc() to support large umems with, on my
server, one million pages or more in the umem.

Reported-by: Dan Siemon &lt;dan@coverfire.com&gt;
Signed-off-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Björn Töpel &lt;bjorn@kernel.org&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20210521083301.26921-1-magnus.karlsson@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>xsk: Fix for xp_aligned_validate_desc() when len == chunk_size</title>
<updated>2021-05-03T22:28:06+00:00</updated>
<author>
<name>Xuan Zhuo</name>
<email>xuanzhuo@linux.alibaba.com</email>
</author>
<published>2021-04-28T09:44:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ac31565c21937eee9117e43c9cd34f557f6f1cb8'/>
<id>ac31565c21937eee9117e43c9cd34f557f6f1cb8</id>
<content type='text'>
When desc-&gt;len is equal to chunk_size, it is legal. But when the
xp_aligned_validate_desc() got chunk_end from desc-&gt;addr + desc-&gt;len
pointing to the next chunk during the check, it caused the check to
fail.

This problem was first introduced in bbff2f321a86 ("xsk: new descriptor
addressing scheme"). Later in 2b43470add8c ("xsk: Introduce AF_XDP buffer
allocation API") this piece of code was moved into the new function called
xp_aligned_validate_desc(). This function was then moved into xsk_queue.h
via 26062b185eee ("xsk: Explicitly inline functions and move definitions").

Fixes: bbff2f321a86 ("xsk: new descriptor addressing scheme")
Signed-off-by: Xuan Zhuo &lt;xuanzhuo@linux.alibaba.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Link: https://lore.kernel.org/bpf/20210428094424.54435-1-xuanzhuo@linux.alibaba.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When desc-&gt;len is equal to chunk_size, it is legal. But when the
xp_aligned_validate_desc() got chunk_end from desc-&gt;addr + desc-&gt;len
pointing to the next chunk during the check, it caused the check to
fail.

This problem was first introduced in bbff2f321a86 ("xsk: new descriptor
addressing scheme"). Later in 2b43470add8c ("xsk: Introduce AF_XDP buffer
allocation API") this piece of code was moved into the new function called
xp_aligned_validate_desc(). This function was then moved into xsk_queue.h
via 26062b185eee ("xsk: Explicitly inline functions and move definitions").

Fixes: bbff2f321a86 ("xsk: new descriptor addressing scheme")
Signed-off-by: Xuan Zhuo &lt;xuanzhuo@linux.alibaba.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Link: https://lore.kernel.org/bpf/20210428094424.54435-1-xuanzhuo@linux.alibaba.com
</pre>
</div>
</content>
</entry>
<entry>
<title>xsk: Align XDP socket batch size with DPDK</title>
<updated>2021-04-23T07:50:35+00:00</updated>
<author>
<name>Li RongQing</name>
<email>lirongqing@baidu.com</email>
</author>
<published>2021-04-14T05:39:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e7a1c1300891d8f11d05b42665e299cc22a4b383'/>
<id>e7a1c1300891d8f11d05b42665e299cc22a4b383</id>
<content type='text'>
DPDK default burst size is 32, however, kernel xsk sendto
syscall can not handle all 32 at one time, and return with
error.

So make kernel XDP socket batch size larger to avoid
unnecessary syscall fail and context switch which will help
to increase performance.

Signed-off-by: Li RongQing &lt;lirongqing@baidu.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Link: https://lore.kernel.org/bpf/1618378752-4191-1-git-send-email-lirongqing@baidu.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
DPDK default burst size is 32, however, kernel xsk sendto
syscall can not handle all 32 at one time, and return with
error.

So make kernel XDP socket batch size larger to avoid
unnecessary syscall fail and context switch which will help
to increase performance.

Signed-off-by: Li RongQing &lt;lirongqing@baidu.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Magnus Karlsson &lt;magnus.karlsson@intel.com&gt;
Link: https://lore.kernel.org/bpf/1618378752-4191-1-git-send-email-lirongqing@baidu.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf, xdp: Restructure redirect actions</title>
<updated>2021-03-10T00:06:34+00:00</updated>
<author>
<name>Björn Töpel</name>
<email>bjorn.topel@intel.com</email>
</author>
<published>2021-03-08T11:29:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ee75aef23afe6e88497151c127c13ed69f41aaa2'/>
<id>ee75aef23afe6e88497151c127c13ed69f41aaa2</id>
<content type='text'>
The XDP_REDIRECT implementations for maps and non-maps are fairly
similar, but obviously need to take different code paths depending on
if the target is using a map or not. Today, the redirect targets for
XDP either uses a map, or is based on ifindex.

Here, the map type and id are added to bpf_redirect_info, instead of
the actual map. Map type, map item/ifindex, and the map_id (if any) is
passed to xdp_do_redirect().

For ifindex-based redirect, used by the bpf_redirect() XDP BFP helper,
a special map type/id are used. Map type of UNSPEC together with map id
equal to INT_MAX has the special meaning of an ifindex based
redirect. Note that valid map ids are 1 inclusive, INT_MAX exclusive
([1,INT_MAX[).

In addition to making the code easier to follow, using explicit type
and id in bpf_redirect_info has a slight positive performance impact
by avoiding a pointer indirection for the map type lookup, and instead
use the cacheline for bpf_redirect_info.

Since the actual map is not passed via bpf_redirect_info anymore, the
map lookup is only done in the BPF helper. This means that the
bpf_clear_redirect_map() function can be removed. The actual map item
is RCU protected.

The bpf_redirect_info flags member is not used by XDP, and not
read/written any more. The map member is only written to when
required/used, and not unconditionally.

Signed-off-by: Björn Töpel &lt;bjorn.topel@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Reviewed-by: Maciej Fijalkowski &lt;maciej.fijalkowski@intel.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210308112907.559576-3-bjorn.topel@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The XDP_REDIRECT implementations for maps and non-maps are fairly
similar, but obviously need to take different code paths depending on
if the target is using a map or not. Today, the redirect targets for
XDP either uses a map, or is based on ifindex.

Here, the map type and id are added to bpf_redirect_info, instead of
the actual map. Map type, map item/ifindex, and the map_id (if any) is
passed to xdp_do_redirect().

For ifindex-based redirect, used by the bpf_redirect() XDP BFP helper,
a special map type/id are used. Map type of UNSPEC together with map id
equal to INT_MAX has the special meaning of an ifindex based
redirect. Note that valid map ids are 1 inclusive, INT_MAX exclusive
([1,INT_MAX[).

In addition to making the code easier to follow, using explicit type
and id in bpf_redirect_info has a slight positive performance impact
by avoiding a pointer indirection for the map type lookup, and instead
use the cacheline for bpf_redirect_info.

Since the actual map is not passed via bpf_redirect_info anymore, the
map lookup is only done in the BPF helper. This means that the
bpf_clear_redirect_map() function can be removed. The actual map item
is RCU protected.

The bpf_redirect_info flags member is not used by XDP, and not
read/written any more. The map member is only written to when
required/used, and not unconditionally.

Signed-off-by: Björn Töpel &lt;bjorn.topel@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Reviewed-by: Maciej Fijalkowski &lt;maciej.fijalkowski@intel.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210308112907.559576-3-bjorn.topel@gmail.com
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf, xdp: Make bpf_redirect_map() a map operation</title>
<updated>2021-03-10T00:06:34+00:00</updated>
<author>
<name>Björn Töpel</name>
<email>bjorn.topel@intel.com</email>
</author>
<published>2021-03-08T11:29:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e6a4750ffe9d701c4d55212b14b615e63571d235'/>
<id>e6a4750ffe9d701c4d55212b14b615e63571d235</id>
<content type='text'>
Currently the bpf_redirect_map() implementation dispatches to the
correct map-lookup function via a switch-statement. To avoid the
dispatching, this change adds bpf_redirect_map() as a map
operation. Each map provides its bpf_redirect_map() version, and
correct function is automatically selected by the BPF verifier.

A nice side-effect of the code movement is that the map lookup
functions are now local to the map implementation files, which removes
one additional function call.

Signed-off-by: Björn Töpel &lt;bjorn.topel@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210308112907.559576-2-bjorn.topel@gmail.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently the bpf_redirect_map() implementation dispatches to the
correct map-lookup function via a switch-statement. To avoid the
dispatching, this change adds bpf_redirect_map() as a map
operation. Each map provides its bpf_redirect_map() version, and
correct function is automatically selected by the BPF verifier.

A nice side-effect of the code movement is that the map lookup
functions are now local to the map implementation files, which removes
one additional function call.

Signed-off-by: Björn Töpel &lt;bjorn.topel@intel.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Toke Høiland-Jørgensen &lt;toke@redhat.com&gt;
Link: https://lore.kernel.org/bpf/20210308112907.559576-2-bjorn.topel@gmail.com
</pre>
</div>
</content>
</entry>
</feed>
