<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/net/openvswitch/datapath.h, branch v5.3-rc3</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 269</title>
<updated>2019-06-05T15:30:29+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-05-29T14:12:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c942299924a70b458320846e53b742ba11e985b3'/>
<id>c942299924a70b458320846e53b742ba11e985b3</id>
<content type='text'>
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin street fifth floor boston ma
  02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 21 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Richard Fontana &lt;rfontana@redhat.com&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141334.228102212@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details you should have received a copy of the gnu general
  public license along with this program if not write to the free
  software foundation inc 51 franklin street fifth floor boston ma
  02110 1301 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 21 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Richard Fontana &lt;rfontana@redhat.com&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141334.228102212@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: Support conntrack zone limit</title>
<updated>2018-05-25T20:45:19+00:00</updated>
<author>
<name>Yi-Hung Wei</name>
<email>yihung.wei@gmail.com</email>
</author>
<published>2018-05-25T00:56:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=11efd5cb04a184eea4f57b68ea63dddd463158d1'/>
<id>11efd5cb04a184eea4f57b68ea63dddd463158d1</id>
<content type='text'>
Currently, nf_conntrack_max is used to limit the maximum number of
conntrack entries in the conntrack table for every network namespace.
For the VMs and containers that reside in the same namespace,
they share the same conntrack table, and the total # of conntrack entries
for all the VMs and containers are limited by nf_conntrack_max.  In this
case, if one of the VM/container abuses the usage the conntrack entries,
it blocks the others from committing valid conntrack entries into the
conntrack table.  Even if we can possibly put the VM in different network
namespace, the current nf_conntrack_max configuration is kind of rigid
that we cannot limit different VM/container to have different # conntrack
entries.

To address the aforementioned issue, this patch proposes to have a
fine-grained mechanism that could further limit the # of conntrack entries
per-zone.  For example, we can designate different zone to different VM,
and set conntrack limit to each zone.  By providing this isolation, a
mis-behaved VM only consumes the conntrack entries in its own zone, and
it will not influence other well-behaved VMs.  Moreover, the users can
set various conntrack limit to different zone based on their preference.

The proposed implementation utilizes Netfilter's nf_conncount backend
to count the number of connections in a particular zone.  If the number of
connection is above a configured limitation, ovs will return ENOMEM to the
userspace.  If userspace does not configure the zone limit, the limit
defaults to zero that is no limitation, which is backward compatible to
the behavior without this patch.

The following high leve APIs are provided to the userspace:
  - OVS_CT_LIMIT_CMD_SET:
    * set default connection limit for all zones
    * set the connection limit for a particular zone
  - OVS_CT_LIMIT_CMD_DEL:
    * remove the connection limit for a particular zone
  - OVS_CT_LIMIT_CMD_GET:
    * get the default connection limit for all zones
    * get the connection limit for a particular zone

Signed-off-by: Yi-Hung Wei &lt;yihung.wei@gmail.com&gt;
Acked-by: Pravin B Shelar &lt;pshelar@ovn.org&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>
Currently, nf_conntrack_max is used to limit the maximum number of
conntrack entries in the conntrack table for every network namespace.
For the VMs and containers that reside in the same namespace,
they share the same conntrack table, and the total # of conntrack entries
for all the VMs and containers are limited by nf_conntrack_max.  In this
case, if one of the VM/container abuses the usage the conntrack entries,
it blocks the others from committing valid conntrack entries into the
conntrack table.  Even if we can possibly put the VM in different network
namespace, the current nf_conntrack_max configuration is kind of rigid
that we cannot limit different VM/container to have different # conntrack
entries.

To address the aforementioned issue, this patch proposes to have a
fine-grained mechanism that could further limit the # of conntrack entries
per-zone.  For example, we can designate different zone to different VM,
and set conntrack limit to each zone.  By providing this isolation, a
mis-behaved VM only consumes the conntrack entries in its own zone, and
it will not influence other well-behaved VMs.  Moreover, the users can
set various conntrack limit to different zone based on their preference.

The proposed implementation utilizes Netfilter's nf_conncount backend
to count the number of connections in a particular zone.  If the number of
connection is above a configured limitation, ovs will return ENOMEM to the
userspace.  If userspace does not configure the zone limit, the limit
defaults to zero that is no limitation, which is backward compatible to
the behavior without this patch.

The following high leve APIs are provided to the userspace:
  - OVS_CT_LIMIT_CMD_SET:
    * set default connection limit for all zones
    * set the connection limit for a particular zone
  - OVS_CT_LIMIT_CMD_DEL:
    * remove the connection limit for a particular zone
  - OVS_CT_LIMIT_CMD_GET:
    * get the default connection limit for all zones
    * get the connection limit for a particular zone

Signed-off-by: Yi-Hung Wei &lt;yihung.wei@gmail.com&gt;
Acked-by: Pravin B Shelar &lt;pshelar@ovn.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: Add meter action support</title>
<updated>2017-11-13T01:37:07+00:00</updated>
<author>
<name>Andy Zhou</name>
<email>azhou@ovn.org</email>
</author>
<published>2017-11-10T20:09:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cd8a6c33693c1b89d2737ffdbf9611564e9ac907'/>
<id>cd8a6c33693c1b89d2737ffdbf9611564e9ac907</id>
<content type='text'>
Implements OVS kernel meter action support.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&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>
Implements OVS kernel meter action support.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: Add meter infrastructure</title>
<updated>2017-11-13T01:37:07+00:00</updated>
<author>
<name>Andy Zhou</name>
<email>azhou@ovn.org</email>
</author>
<published>2017-11-10T20:09:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=96fbc13d7e770b542d2d1fcf700d0baadc6e8063'/>
<id>96fbc13d7e770b542d2d1fcf700d0baadc6e8063</id>
<content type='text'>
OVS kernel datapath so far does not support Openflow meter action.
This is the first stab at adding kernel datapath meter support.
This implementation supports only drop band type.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&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>
OVS kernel datapath so far does not support Openflow meter action.
This is the first stab at adding kernel datapath meter support.
This implementation supports only drop band type.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: export get_dp() API.</title>
<updated>2017-11-13T01:37:07+00:00</updated>
<author>
<name>Andy Zhou</name>
<email>azhou@ovn.org</email>
</author>
<published>2017-11-10T20:09:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9602c01e57f7b868d748c2ba2aef0efa64b71ffc'/>
<id>9602c01e57f7b868d748c2ba2aef0efa64b71ffc</id>
<content type='text'>
Later patches will invoke get_dp() outside of datapath.c. Export it.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&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>
Later patches will invoke get_dp() outside of datapath.c. Export it.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: reliable interface indentification in port dumps</title>
<updated>2017-11-05T12:49:17+00:00</updated>
<author>
<name>Jiri Benc</name>
<email>jbenc@redhat.com</email>
</author>
<published>2017-11-02T19:04:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9354d452034273a50a4fd703bea31e5d6b1fc20b'/>
<id>9354d452034273a50a4fd703bea31e5d6b1fc20b</id>
<content type='text'>
This patch allows reliable identification of netdevice interfaces connected
to openvswitch bridges. In particular, user space queries the netdev
interfaces belonging to the ports for statistics, up/down state, etc.
Datapath dump needs to provide enough information for the user space to be
able to do that.

Currently, only interface names are returned. This is not sufficient, as
openvswitch allows its ports to be in different name spaces and the
interface name is valid only in its name space. What is needed and generally
used in other netlink APIs, is the pair ifindex+netnsid.

The solution is addition of the ifindex+netnsid pair (or only ifindex if in
the same name space) to vport get/dump operation.

On request side, ideally the ifindex+netnsid pair could be used to
get/set/del the corresponding vport. This is not implemented by this patch
and can be added later if needed.

Signed-off-by: Jiri Benc &lt;jbenc@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 allows reliable identification of netdevice interfaces connected
to openvswitch bridges. In particular, user space queries the netdev
interfaces belonging to the ports for statistics, up/down state, etc.
Datapath dump needs to provide enough information for the user space to be
able to do that.

Currently, only interface names are returned. This is not sufficient, as
openvswitch allows its ports to be in different name spaces and the
interface name is valid only in its name space. What is needed and generally
used in other netlink APIs, is the pair ifindex+netnsid.

The solution is addition of the ifindex+netnsid pair (or only ifindex if in
the same name space) to vport get/dump operation.

On request side, ideally the ifindex+netnsid pair could be used to
get/set/del the corresponding vport. This is not implemented by this patch
and can be added later if needed.

Signed-off-by: Jiri Benc &lt;jbenc@redhat.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: fix skb_panic due to the incorrect actions attrlen</title>
<updated>2017-08-16T21:12:37+00:00</updated>
<author>
<name>Liping Zhang</name>
<email>zlpnobody@gmail.com</email>
</author>
<published>2017-08-16T05:30:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=494bea39f3201776cdfddc232705f54a0bd210c4'/>
<id>494bea39f3201776cdfddc232705f54a0bd210c4</id>
<content type='text'>
For sw_flow_actions, the actions_len only represents the kernel part's
size, and when we dump the actions to the userspace, we will do the
convertions, so it's true size may become bigger than the actions_len.

But unfortunately, for OVS_PACKET_ATTR_ACTIONS, we use the actions_len
to alloc the skbuff, so the user_skb's size may become insufficient and
oops will happen like this:
  skbuff: skb_over_panic: text:ffffffff8148fabf len:1749 put:157 head:
  ffff881300f39000 data:ffff881300f39000 tail:0x6d5 end:0x6c0 dev:&lt;NULL&gt;
  ------------[ cut here ]------------
  kernel BUG at net/core/skbuff.c:129!
  [...]
  Call Trace:
   &lt;IRQ&gt;
   [&lt;ffffffff8148be82&gt;] skb_put+0x43/0x44
   [&lt;ffffffff8148fabf&gt;] skb_zerocopy+0x6c/0x1f4
   [&lt;ffffffffa0290d36&gt;] queue_userspace_packet+0x3a3/0x448 [openvswitch]
   [&lt;ffffffffa0292023&gt;] ovs_dp_upcall+0x30/0x5c [openvswitch]
   [&lt;ffffffffa028d435&gt;] output_userspace+0x132/0x158 [openvswitch]
   [&lt;ffffffffa01e6890&gt;] ? ip6_rcv_finish+0x74/0x77 [ipv6]
   [&lt;ffffffffa028e277&gt;] do_execute_actions+0xcc1/0xdc8 [openvswitch]
   [&lt;ffffffffa028e3f2&gt;] ovs_execute_actions+0x74/0x106 [openvswitch]
   [&lt;ffffffffa0292130&gt;] ovs_dp_process_packet+0xe1/0xfd [openvswitch]
   [&lt;ffffffffa0292b77&gt;] ? key_extract+0x63c/0x8d5 [openvswitch]
   [&lt;ffffffffa029848b&gt;] ovs_vport_receive+0xa1/0xc3 [openvswitch]
  [...]

Also we can find that the actions_len is much little than the orig_len:
  crash&gt; struct sw_flow_actions 0xffff8812f539d000
  struct sw_flow_actions {
    rcu = {
      next = 0xffff8812f5398800,
      func = 0xffffe3b00035db32
    },
    orig_len = 1384,
    actions_len = 592,
    actions = 0xffff8812f539d01c
  }

So as a quick fix, use the orig_len instead of the actions_len to alloc
the user_skb.

Last, this oops happened on our system running a relative old kernel, but
the same risk still exists on the mainline, since we use the wrong
actions_len from the beginning.

Fixes: ccea74457bbd ("openvswitch: include datapath actions with sampled-packet upcall to userspace")
Cc: Neil McKee &lt;neil.mckee@inmon.com&gt;
Signed-off-by: Liping Zhang &lt;zlpnobody@gmail.com&gt;
Acked-by: Pravin B Shelar &lt;pshelar@ovn.org&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>
For sw_flow_actions, the actions_len only represents the kernel part's
size, and when we dump the actions to the userspace, we will do the
convertions, so it's true size may become bigger than the actions_len.

But unfortunately, for OVS_PACKET_ATTR_ACTIONS, we use the actions_len
to alloc the skbuff, so the user_skb's size may become insufficient and
oops will happen like this:
  skbuff: skb_over_panic: text:ffffffff8148fabf len:1749 put:157 head:
  ffff881300f39000 data:ffff881300f39000 tail:0x6d5 end:0x6c0 dev:&lt;NULL&gt;
  ------------[ cut here ]------------
  kernel BUG at net/core/skbuff.c:129!
  [...]
  Call Trace:
   &lt;IRQ&gt;
   [&lt;ffffffff8148be82&gt;] skb_put+0x43/0x44
   [&lt;ffffffff8148fabf&gt;] skb_zerocopy+0x6c/0x1f4
   [&lt;ffffffffa0290d36&gt;] queue_userspace_packet+0x3a3/0x448 [openvswitch]
   [&lt;ffffffffa0292023&gt;] ovs_dp_upcall+0x30/0x5c [openvswitch]
   [&lt;ffffffffa028d435&gt;] output_userspace+0x132/0x158 [openvswitch]
   [&lt;ffffffffa01e6890&gt;] ? ip6_rcv_finish+0x74/0x77 [ipv6]
   [&lt;ffffffffa028e277&gt;] do_execute_actions+0xcc1/0xdc8 [openvswitch]
   [&lt;ffffffffa028e3f2&gt;] ovs_execute_actions+0x74/0x106 [openvswitch]
   [&lt;ffffffffa0292130&gt;] ovs_dp_process_packet+0xe1/0xfd [openvswitch]
   [&lt;ffffffffa0292b77&gt;] ? key_extract+0x63c/0x8d5 [openvswitch]
   [&lt;ffffffffa029848b&gt;] ovs_vport_receive+0xa1/0xc3 [openvswitch]
  [...]

Also we can find that the actions_len is much little than the orig_len:
  crash&gt; struct sw_flow_actions 0xffff8812f539d000
  struct sw_flow_actions {
    rcu = {
      next = 0xffff8812f5398800,
      func = 0xffffe3b00035db32
    },
    orig_len = 1384,
    actions_len = 592,
    actions = 0xffff8812f539d01c
  }

So as a quick fix, use the orig_len instead of the actions_len to alloc
the user_skb.

Last, this oops happened on our system running a relative old kernel, but
the same risk still exists on the mainline, since we use the wrong
actions_len from the beginning.

Fixes: ccea74457bbd ("openvswitch: include datapath actions with sampled-packet upcall to userspace")
Cc: Neil McKee &lt;neil.mckee@inmon.com&gt;
Signed-off-by: Liping Zhang &lt;zlpnobody@gmail.com&gt;
Acked-by: Pravin B Shelar &lt;pshelar@ovn.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: fix mis-ordered comment lines for ovs_skb_cb</title>
<updated>2017-07-03T12:54:00+00:00</updated>
<author>
<name>Daniel Axtens</name>
<email>dja@axtens.net</email>
</author>
<published>2017-07-03T11:46:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=52427fa0631269c62885dc48e0c32e2ad6e17f8c'/>
<id>52427fa0631269c62885dc48e0c32e2ad6e17f8c</id>
<content type='text'>
I was trying to wrap my head around meaning of mru, and realised
that the second line of the comment defining it had somehow
ended up after the line defining cutlen, leading to much confusion.

Reorder the lines to make sense.

Signed-off-by: Daniel Axtens &lt;dja@axtens.net&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>
I was trying to wrap my head around meaning of mru, and realised
that the second line of the comment defining it had somehow
ended up after the line defining cutlen, leading to much confusion.

Reorder the lines to make sense.

Signed-off-by: Daniel Axtens &lt;dja@axtens.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>openvswitch: Optimize sample action for the clone use cases</title>
<updated>2017-03-22T18:28:35+00:00</updated>
<author>
<name>andy zhou</name>
<email>azhou@ovn.org</email>
</author>
<published>2017-03-20T23:32:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=798c166173ffb50128993641fcf791df51bed48e'/>
<id>798c166173ffb50128993641fcf791df51bed48e</id>
<content type='text'>
With the introduction of open flow 'clone' action, the OVS user space
can now translate the 'clone' action into kernel datapath 'sample'
action, with 100% probability, to ensure that the clone semantics,
which is that the packet seen by the clone action is the same as the
packet seen by the action after clone, is faithfully carried out
in the datapath.

While the sample action in the datpath has the matching semantics,
its implementation is only optimized for its original use.
Specifically, there are two limitation: First, there is a 3 level of
nesting restriction, enforced at the flow downloading time. This
limit turns out to be too restrictive for the 'clone' use case.
Second, the implementation avoid recursive call only if the sample
action list has a single userspace action.

The main optimization implemented in this series removes the static
nesting limit check, instead, implement the run time recursion limit
check, and recursion avoidance similar to that of the 'recirc' action.
This optimization solve both #1 and #2 issues above.

One related optimization attempts to avoid copying flow key as
long as the actions enclosed does not change the flow key. The
detection is performed only once at the flow downloading time.

Another related optimization is to rewrite the action list
at flow downloading time in order to save the fast path from parsing
the sample action list in its original form repeatedly.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&gt;
Acked-by: Pravin B Shelar &lt;pshelar@ovn.org&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>
With the introduction of open flow 'clone' action, the OVS user space
can now translate the 'clone' action into kernel datapath 'sample'
action, with 100% probability, to ensure that the clone semantics,
which is that the packet seen by the clone action is the same as the
packet seen by the action after clone, is faithfully carried out
in the datapath.

While the sample action in the datpath has the matching semantics,
its implementation is only optimized for its original use.
Specifically, there are two limitation: First, there is a 3 level of
nesting restriction, enforced at the flow downloading time. This
limit turns out to be too restrictive for the 'clone' use case.
Second, the implementation avoid recursive call only if the sample
action list has a single userspace action.

The main optimization implemented in this series removes the static
nesting limit check, instead, implement the run time recursion limit
check, and recursion avoidance similar to that of the 'recirc' action.
This optimization solve both #1 and #2 issues above.

One related optimization attempts to avoid copying flow key as
long as the actions enclosed does not change the flow key. The
detection is performed only once at the flow downloading time.

Another related optimization is to rewrite the action list
at flow downloading time in order to save the fast path from parsing
the sample action list in its original form repeatedly.

Signed-off-by: Andy Zhou &lt;azhou@ovn.org&gt;
Acked-by: Pravin B Shelar &lt;pshelar@ovn.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netns: make struct pernet_operations::id unsigned int</title>
<updated>2016-11-18T15:59:15+00:00</updated>
<author>
<name>Alexey Dobriyan</name>
<email>adobriyan@gmail.com</email>
</author>
<published>2016-11-17T01:58:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=c7d03a00b56fc23c3a01a8353789ad257363e281'/>
<id>c7d03a00b56fc23c3a01a8353789ad257363e281</id>
<content type='text'>
Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

	void f(long *p, int i)
	{
		g(p[i]);
	}

  roughly translates to

	movsx	rsi, esi
	mov	rdi, [rsi+...]
	call 	g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

	static inline void *net_generic(const struct net *net, int id)
	{
		...
		ptr = ng-&gt;ptr[id - 1];
		...
	}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
	function                                     old     new   delta
	nfsd4_lock                                  3886    3959     +73
	tipc_link_build_proto_msg                   1096    1140     +44
	mac80211_hwsim_new_radio                    2776    2808     +32
	tipc_mon_rcv                                1032    1058     +26
	svcauth_gss_legacy_init                     1413    1429     +16
	tipc_bcbase_select_primary                   379     392     +13
	nfsd4_exchange_id                           1247    1260     +13
	nfsd4_setclientid_confirm                    782     793     +11
		...
	put_client_renew_locked                      494     480     -14
	ip_set_sockfn_get                            730     716     -14
	geneve_sock_add                              829     813     -16
	nfsd4_sequence_done                          721     703     -18
	nlmclnt_lookup_host                          708     686     -22
	nfsd4_lockt                                 1085    1063     -22
	nfs_get_client                              1077    1050     -27
	tcf_bpf_init                                1106    1076     -30
	nfsd4_encode_fattr                          5997    5930     -67
	Total: Before=154856051, After=154854321, chg -0.00%

Signed-off-by: Alexey Dobriyan &lt;adobriyan@gmail.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>
Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

	void f(long *p, int i)
	{
		g(p[i]);
	}

  roughly translates to

	movsx	rsi, esi
	mov	rdi, [rsi+...]
	call 	g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

	static inline void *net_generic(const struct net *net, int id)
	{
		...
		ptr = ng-&gt;ptr[id - 1];
		...
	}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
	function                                     old     new   delta
	nfsd4_lock                                  3886    3959     +73
	tipc_link_build_proto_msg                   1096    1140     +44
	mac80211_hwsim_new_radio                    2776    2808     +32
	tipc_mon_rcv                                1032    1058     +26
	svcauth_gss_legacy_init                     1413    1429     +16
	tipc_bcbase_select_primary                   379     392     +13
	nfsd4_exchange_id                           1247    1260     +13
	nfsd4_setclientid_confirm                    782     793     +11
		...
	put_client_renew_locked                      494     480     -14
	ip_set_sockfn_get                            730     716     -14
	geneve_sock_add                              829     813     -16
	nfsd4_sequence_done                          721     703     -18
	nlmclnt_lookup_host                          708     686     -22
	nfsd4_lockt                                 1085    1063     -22
	nfs_get_client                              1077    1050     -27
	tcf_bpf_init                                1106    1076     -30
	nfsd4_encode_fattr                          5997    5930     -67
	Total: Before=154856051, After=154854321, chg -0.00%

Signed-off-by: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
