<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/dcb, branch v4.18.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>treewide: kmalloc() -&gt; kmalloc_array()</title>
<updated>2018-06-12T23:19:22+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2018-06-12T20:55:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6da2ec56059c3c7a7e5f729e6349e74ace1e5c57'/>
<id>6da2ec56059c3c7a7e5f729e6349e74ace1e5c57</id>
<content type='text'>
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net/dcb: Add dcbnl buffer attribute</title>
<updated>2018-05-24T21:22:59+00:00</updated>
<author>
<name>Huy Nguyen</name>
<email>huyn@mellanox.com</email>
</author>
<published>2018-02-22T17:57:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e549f6f9c098067a99e9de8ac84f5cc2c07ae5c6'/>
<id>e549f6f9c098067a99e9de8ac84f5cc2c07ae5c6</id>
<content type='text'>
In this patch, we add dcbnl buffer attribute to allow user
change the NIC's buffer configuration such as priority
to buffer mapping and buffer size of individual buffer.

This attribute combined with pfc attribute allows advanced user to
fine tune the qos setting for specific priority queue. For example,
user can give dedicated buffer for one or more priorities or user
can give large buffer to certain priorities.

The dcb buffer configuration will be controlled by lldptool.
lldptool -T -i eth2 -V BUFFER prio 0,2,5,7,1,2,3,6
  maps priorities 0,1,2,3,4,5,6,7 to receive buffer 0,2,5,7,1,2,3,6
lldptool -T -i eth2 -V BUFFER size 87296,87296,0,87296,0,0,0,0
  sets receive buffer size for buffer 0,1,2,3,4,5,6,7 respectively

After discussion on mailing list with Jakub, Jiri, Ido and John, we agreed to
choose dcbnl over devlink interface since this feature is intended to set
port attributes which are governed by the netdev instance of that port, where
devlink API is more suitable for global ASIC configurations.

We present an use case scenario where dcbnl buffer attribute configured
by advance user helps reduce the latency of messages of different sizes.

Scenarios description:
On ConnectX-5, we run latency sensitive traffic with
small/medium message sizes ranging from 64B to 256KB and bandwidth sensitive
traffic with large messages sizes 512KB and 1MB. We group small, medium,
and large message sizes to their own pfc enables priorities as follow.
  Priorities 1 &amp; 2 (64B, 256B and 1KB)
  Priorities 3 &amp; 4 (4KB, 8KB, 16KB, 64KB, 128KB and 256KB)
  Priorities 5 &amp; 6 (512KB and 1MB)

By default, ConnectX-5 maps all pfc enabled priorities to a single
lossless fixed buffer size of 50% of total available buffer space. The
other 50% is assigned to lossy buffer. Using dcbnl buffer attribute,
we create three equal size lossless buffers. Each buffer has 25% of total
available buffer space. Thus, the lossy buffer size reduces to 25%. Priority
to lossless  buffer mappings are set as follow.
  Priorities 1 &amp; 2 on lossless buffer #1
  Priorities 3 &amp; 4 on lossless buffer #2
  Priorities 5 &amp; 6 on lossless buffer #3

We observe improvements in latency for small and medium message sizes
as follows. Please note that the large message sizes bandwidth performance is
reduced but the total bandwidth remains the same.
  256B message size (42 % latency reduction)
  4K message size (21% latency reduction)
  64K message size (16% latency reduction)

CC: Ido Schimmel &lt;idosch@idosch.org&gt;
CC: Jakub Kicinski &lt;jakub.kicinski@netronome.com&gt;
CC: Jiri Pirko &lt;jiri@resnulli.us&gt;
CC: Or Gerlitz &lt;gerlitz.or@gmail.com&gt;
CC: Parav Pandit &lt;parav@mellanox.com&gt;
CC: Aron Silverton &lt;aron.silverton@oracle.com&gt;
Signed-off-by: Huy Nguyen &lt;huyn@mellanox.com&gt;
Reviewed-by: Parav Pandit &lt;parav@mellanox.com&gt;
Signed-off-by: Saeed Mahameed &lt;saeedm@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In this patch, we add dcbnl buffer attribute to allow user
change the NIC's buffer configuration such as priority
to buffer mapping and buffer size of individual buffer.

This attribute combined with pfc attribute allows advanced user to
fine tune the qos setting for specific priority queue. For example,
user can give dedicated buffer for one or more priorities or user
can give large buffer to certain priorities.

The dcb buffer configuration will be controlled by lldptool.
lldptool -T -i eth2 -V BUFFER prio 0,2,5,7,1,2,3,6
  maps priorities 0,1,2,3,4,5,6,7 to receive buffer 0,2,5,7,1,2,3,6
lldptool -T -i eth2 -V BUFFER size 87296,87296,0,87296,0,0,0,0
  sets receive buffer size for buffer 0,1,2,3,4,5,6,7 respectively

After discussion on mailing list with Jakub, Jiri, Ido and John, we agreed to
choose dcbnl over devlink interface since this feature is intended to set
port attributes which are governed by the netdev instance of that port, where
devlink API is more suitable for global ASIC configurations.

We present an use case scenario where dcbnl buffer attribute configured
by advance user helps reduce the latency of messages of different sizes.

Scenarios description:
On ConnectX-5, we run latency sensitive traffic with
small/medium message sizes ranging from 64B to 256KB and bandwidth sensitive
traffic with large messages sizes 512KB and 1MB. We group small, medium,
and large message sizes to their own pfc enables priorities as follow.
  Priorities 1 &amp; 2 (64B, 256B and 1KB)
  Priorities 3 &amp; 4 (4KB, 8KB, 16KB, 64KB, 128KB and 256KB)
  Priorities 5 &amp; 6 (512KB and 1MB)

By default, ConnectX-5 maps all pfc enabled priorities to a single
lossless fixed buffer size of 50% of total available buffer space. The
other 50% is assigned to lossy buffer. Using dcbnl buffer attribute,
we create three equal size lossless buffers. Each buffer has 25% of total
available buffer space. Thus, the lossy buffer size reduces to 25%. Priority
to lossless  buffer mappings are set as follow.
  Priorities 1 &amp; 2 on lossless buffer #1
  Priorities 3 &amp; 4 on lossless buffer #2
  Priorities 5 &amp; 6 on lossless buffer #3

We observe improvements in latency for small and medium message sizes
as follows. Please note that the large message sizes bandwidth performance is
reduced but the total bandwidth remains the same.
  256B message size (42 % latency reduction)
  4K message size (21% latency reduction)
  64K message size (16% latency reduction)

CC: Ido Schimmel &lt;idosch@idosch.org&gt;
CC: Jakub Kicinski &lt;jakub.kicinski@netronome.com&gt;
CC: Jiri Pirko &lt;jiri@resnulli.us&gt;
CC: Or Gerlitz &lt;gerlitz.or@gmail.com&gt;
CC: Parav Pandit &lt;parav@mellanox.com&gt;
CC: Aron Silverton &lt;aron.silverton@oracle.com&gt;
Signed-off-by: Huy Nguyen &lt;huyn@mellanox.com&gt;
Reviewed-by: Parav Pandit &lt;parav@mellanox.com&gt;
Signed-off-by: Saeed Mahameed &lt;saeedm@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rtnetlink: make rtnl_register accept a flags parameter</title>
<updated>2017-08-09T23:57:38+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2017-08-09T18:41:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b97bac64a589d0158cf866e8995e831030f68f4f'/>
<id>b97bac64a589d0158cf866e8995e831030f68f4f</id>
<content type='text'>
This change allows us to later indicate to rtnetlink core that certain
doit functions should be called without acquiring rtnl_mutex.

This change should have no effect, we simply replace the last (now
unused) calcit argument with the new flag.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Reviewed-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.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>
This change allows us to later indicate to rtnetlink core that certain
doit functions should be called without acquiring rtnl_mutex.

This change should have no effect, we simply replace the last (now
unused) calcit argument with the new flag.

Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Reviewed-by: Hannes Frederic Sowa &lt;hannes@stressinduktion.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>dcb: enforce minimum length on IEEE_APPS attribute</title>
<updated>2017-05-21T17:42:33+00:00</updated>
<author>
<name>stephen hemminger</name>
<email>stephen@networkplumber.org</email>
</author>
<published>2017-05-19T16:55:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=332b4fc88698dd0429924a61e09d1734940d80a0'/>
<id>332b4fc88698dd0429924a61e09d1734940d80a0</id>
<content type='text'>
Found by reviewing the warning about unused policy table.
The code implies that it meant to check for size, but since
it unrolled the loop for attribute validation that is never used.
Instead do explicit check for attribute.

Compile tested only. Needs review by original author.

Signed-off-by: Stephen Hemminger &lt;sthemmin@microsoft.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>
Found by reviewing the warning about unused policy table.
The code implies that it meant to check for size, but since
it unrolled the loop for attribute validation that is never used.
Instead do explicit check for attribute.

Compile tested only. Needs review by original author.

Signed-off-by: Stephen Hemminger &lt;sthemmin@microsoft.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: rtnetlink: plumb extended ack to doit function</title>
<updated>2017-04-17T19:35:38+00:00</updated>
<author>
<name>David Ahern</name>
<email>dsa@cumulusnetworks.com</email>
</author>
<published>2017-04-16T16:48:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c21ef3e343ae916ad3cfd4dc6ef6791c1f80a010'/>
<id>c21ef3e343ae916ad3cfd4dc6ef6791c1f80a010</id>
<content type='text'>
Add netlink_ext_ack arg to rtnl_doit_func. Pass extack arg to nlmsg_parse
for doit functions that call it directly.

This is the first step to using extended error reporting in rtnetlink.
&gt;From here individual subsystems can be updated to set netlink_ext_ack as
needed.

Signed-off-by: David Ahern &lt;dsa@cumulusnetworks.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>
Add netlink_ext_ack arg to rtnl_doit_func. Pass extack arg to nlmsg_parse
for doit functions that call it directly.

This is the first step to using extended error reporting in rtnetlink.
&gt;From here individual subsystems can be updated to set netlink_ext_ack as
needed.

Signed-off-by: David Ahern &lt;dsa@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>netlink: pass extended ACK struct to parsing functions</title>
<updated>2017-04-13T17:58:22+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2017-04-12T12:34:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fceb6435e85298f747fee938415057af837f5a8a'/>
<id>fceb6435e85298f747fee938415057af837f5a8a</id>
<content type='text'>
Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.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>
Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: dcb: set error code on failures</title>
<updated>2016-12-04T04:54:25+00:00</updated>
<author>
<name>Pan Bian</name>
<email>bianpan2016@163.com</email>
</author>
<published>2016-12-03T13:49:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c66ebf2db555c6ed705044eabd2b37dcd546f68b'/>
<id>c66ebf2db555c6ed705044eabd2b37dcd546f68b</id>
<content type='text'>
In function dcbnl_cee_fill(), returns the value of variable err on
errors. However, on some error paths (e.g. nla put fails), its value may
be 0. It may be better to explicitly set a negative errno to variable
err before returning.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188881

Signed-off-by: Pan Bian &lt;bianpan2016@163.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>
In function dcbnl_cee_fill(), returns the value of variable err on
errors. However, on some error paths (e.g. nla put fails), its value may
be 0. It may be better to explicitly set a negative errno to variable
err before returning.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188881

Signed-off-by: Pan Bian &lt;bianpan2016@163.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net/dcb: make dcbnl.c explicitly non-modular</title>
<updated>2015-10-09T14:52:27+00:00</updated>
<author>
<name>Paul Gortmaker</name>
<email>paul.gortmaker@windriver.com</email>
</author>
<published>2015-10-07T21:27:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=36b9ad8084bd7ecf6d2241beca23e71f5f4b0cf1'/>
<id>36b9ad8084bd7ecf6d2241beca23e71f5f4b0cf1</id>
<content type='text'>
The Kconfig currently controlling compilation of this code is:

net/dcb/Kconfig:config DCB
net/dcb/Kconfig:        bool "Data Center Bridging support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.  We can
change to one of the other priority initcalls (subsys?) at any later
date, if desired.

We also delete the MODULE_LICENSE tag etc. since all that information
is (or is now) already contained at the top of the file in the comments.

Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Or Gerlitz &lt;ogerlitz@mellanox.com&gt;
Cc: Anish Bhatt &lt;anish@chelsio.com&gt;
Cc: John Fastabend &lt;john.r.fastabend@intel.com&gt;
Cc: Shani Michaeli &lt;shanim@mellanox.com&gt;
Cc: netdev@vger.kernel.org
Signed-off-by: Paul Gortmaker &lt;paul.gortmaker@windriver.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>
The Kconfig currently controlling compilation of this code is:

net/dcb/Kconfig:config DCB
net/dcb/Kconfig:        bool "Data Center Bridging support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.  We can
change to one of the other priority initcalls (subsys?) at any later
date, if desired.

We also delete the MODULE_LICENSE tag etc. since all that information
is (or is now) already contained at the top of the file in the comments.

Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Or Gerlitz &lt;ogerlitz@mellanox.com&gt;
Cc: Anish Bhatt &lt;anish@chelsio.com&gt;
Cc: John Fastabend &lt;john.r.fastabend@intel.com&gt;
Cc: Shani Michaeli &lt;shanim@mellanox.com&gt;
Cc: netdev@vger.kernel.org
Signed-off-by: Paul Gortmaker &lt;paul.gortmaker@windriver.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net/dcb: Add IEEE QCN attribute</title>
<updated>2015-03-07T02:50:02+00:00</updated>
<author>
<name>Shani Michaeli</name>
<email>shanim@mellanox.com</email>
</author>
<published>2015-03-05T18:16:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c93682477bd861744589215515a63b81fdbd8948'/>
<id>c93682477bd861744589215515a63b81fdbd8948</id>
<content type='text'>
As specified in 802.1Qau spec. Add this optional attribute to the
DCB netlink layer. To allow for application to use the new attribute,
NIC drivers should implement and register the  callbacks ieee_getqcn,
ieee_setqcn and ieee_getqcnstats.

The QCN attribute holds a set of parameters for management, and
a set of statistics to provide informative data on Congestion-Control
defined by this spec.

Signed-off-by: Shani Michaeli &lt;shanim@mellanox.com&gt;
Signed-off-by: Shachar Raindel &lt;raindel@mellanox.com&gt;
Signed-off-by: Or Gerlitz &lt;ogerlitz@mellanox.com&gt;
Acked-by: John Fastabend &lt;john.r.fastabend@intel.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>
As specified in 802.1Qau spec. Add this optional attribute to the
DCB netlink layer. To allow for application to use the new attribute,
NIC drivers should implement and register the  callbacks ieee_getqcn,
ieee_setqcn and ieee_getqcnstats.

The QCN attribute holds a set of parameters for management, and
a set of statistics to provide informative data on Congestion-Control
defined by this spec.

Signed-off-by: Shani Michaeli &lt;shanim@mellanox.com&gt;
Signed-off-by: Shachar Raindel &lt;raindel@mellanox.com&gt;
Signed-off-by: Or Gerlitz &lt;ogerlitz@mellanox.com&gt;
Acked-by: John Fastabend &lt;john.r.fastabend@intel.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>dcbnl : Disable software interrupts before taking dcb_lock</title>
<updated>2014-11-16T19:50:52+00:00</updated>
<author>
<name>Anish Bhatt</name>
<email>anish@chelsio.com</email>
</author>
<published>2014-11-15T00:38:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=52cff74eef5dd7bdab759300e7d1ca36eba18254'/>
<id>52cff74eef5dd7bdab759300e7d1ca36eba18254</id>
<content type='text'>
Solves possible lockup issues that can be seen from firmware DCB agents calling
into the DCB app api.

DCB firmware event queues can be tied in with NAPI so that dcb events are
generated in softIRQ context. This can results in calls to dcb_*app()
functions which try to take the dcb_lock.

If the the event triggers while we also have the dcb_lock because lldpad or
some other agent happened to be issuing a  get/set command we could see a cpu
lockup.

This code was not originally written with firmware agents in mind, hence
grabbing dcb_lock from softIRQ context was not considered.

Signed-off-by: Anish Bhatt &lt;anish@chelsio.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>
Solves possible lockup issues that can be seen from firmware DCB agents calling
into the DCB app api.

DCB firmware event queues can be tied in with NAPI so that dcb events are
generated in softIRQ context. This can results in calls to dcb_*app()
functions which try to take the dcb_lock.

If the the event triggers while we also have the dcb_lock because lldpad or
some other agent happened to be issuing a  get/set command we could see a cpu
lockup.

This code was not originally written with firmware agents in mind, hence
grabbing dcb_lock from softIRQ context was not considered.

Signed-off-by: Anish Bhatt &lt;anish@chelsio.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
