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<title>lwn.git/kernel/bpf/arraymap.c, branch docs-4.16</title>
<subtitle>Linux kernel documentation tree maintained by Jonathan Corbet</subtitle>
<id>http://mirrors.hust.edu.cn/git/lwn.git/atom?h=docs-4.16</id>
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<updated>2017-10-22T12:39:14+00:00</updated>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net</title>
<updated>2017-10-22T12:39:14+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@davemloft.net</email>
</author>
<published>2017-10-22T12:36:53+00:00</published>
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<id>urn:sha1:f8ddadc4db6c7b7029b6d0e0d9af24f74ad27ca2</id>
<content type='text'>
There were quite a few overlapping sets of changes here.

Daniel's bug fix for off-by-ones in the new BPF branch instructions,
along with the added allowances for "data_end &gt; ptr + x" forms
collided with the metadata additions.

Along with those three changes came veritifer test cases, which in
their final form I tried to group together properly.  If I had just
trimmed GIT's conflict tags as-is, this would have split up the
meta tests unnecessarily.

In the socketmap code, a set of preemption disabling changes
overlapped with the rename of bpf_compute_data_end() to
bpf_compute_data_pointers().

Changes were made to the mv88e6060.c driver set addr method
which got removed in net-next.

The hyperv transport socket layer had a locking change in 'net'
which overlapped with a change of socket state macro usage
in 'net-next'.

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: Add file mode configuration into bpf maps</title>
<updated>2017-10-20T12:32:59+00:00</updated>
<author>
<name>Chenbo Feng</name>
<email>fengc@google.com</email>
</author>
<published>2017-10-18T20:00:22+00:00</published>
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<id>urn:sha1:6e71b04a82248ccf13a94b85cbc674a9fefe53f5</id>
<content type='text'>
Introduce the map read/write flags to the eBPF syscalls that returns the
map fd. The flags is used to set up the file mode when construct a new
file descriptor for bpf maps. To not break the backward capability, the
f_flags is set to O_RDWR if the flag passed by syscall is 0. Otherwise
it should be O_RDONLY or O_WRONLY. When the userspace want to modify or
read the map content, it will check the file mode to see if it is
allowed to make the change.

Signed-off-by: Chenbo Feng &lt;fengc@google.com&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: do not test for PCPU_MIN_UNIT_SIZE before percpu allocations</title>
<updated>2017-10-19T12:13:50+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2017-10-17T14:55:54+00:00</published>
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<id>urn:sha1:bc6d5031b43a2291de638ab9304320b4cae61689</id>
<content type='text'>
PCPU_MIN_UNIT_SIZE is an implementation detail of the percpu
allocator. Given we support __GFP_NOWARN now, lets just let
the allocation request fail naturally instead. The two call
sites from BPF mistakenly assumed __GFP_NOWARN would work, so
no changes needed to their actual __alloc_percpu_gfp() calls
which use the flag already.

Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: perf event change needed for subsequent bpf helpers</title>
<updated>2017-10-07T22:05:57+00:00</updated>
<author>
<name>Yonghong Song</name>
<email>yhs@fb.com</email>
</author>
<published>2017-10-05T16:19:19+00:00</published>
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<id>urn:sha1:97562633bcbac4a07d605ae628d7655fa71caaf5</id>
<content type='text'>
This patch does not impact existing functionalities.
It contains the changes in perf event area needed for
subsequent bpf_perf_event_read_value and
bpf_perf_prog_read_value helpers.

Signed-off-by: Yonghong Song &lt;yhs@fb.com&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: inline map in map lookup functions for array and htab</title>
<updated>2017-08-20T04:56:34+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2017-08-19T01:12:46+00:00</published>
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<id>urn:sha1:7b0c2a0508b90fce79d3782b2e55d0e8bf6a283e</id>
<content type='text'>
Avoid two successive functions calls for the map in map lookup, first
is the bpf_map_lookup_elem() helper call, and second the callback via
map-&gt;ops-&gt;map_lookup_elem() to get to the map in map implementation.
Implementation inlines array and htab flavor for map in map lookups.

Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: Allow selecting numa node during map creation</title>
<updated>2017-08-20T04:35:43+00:00</updated>
<author>
<name>Martin KaFai Lau</name>
<email>kafai@fb.com</email>
</author>
<published>2017-08-18T18:28:00+00:00</published>
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<id>urn:sha1:96eabe7a40aa17e613cf3db2c742ee8b1fc764d0</id>
<content type='text'>
The current map creation API does not allow to provide the numa-node
preference.  The memory usually comes from where the map-creation-process
is running.  The performance is not ideal if the bpf_prog is known to
always run in a numa node different from the map-creation-process.

One of the use case is sharding on CPU to different LRU maps (i.e.
an array of LRU maps).  Here is the test result of map_perf_test on
the INNER_LRU_HASH_PREALLOC test if we force the lru map used by
CPU0 to be allocated from a remote numa node:

[ The machine has 20 cores. CPU0-9 at node 0. CPU10-19 at node 1 ]

&gt;# taskset -c 10 ./map_perf_test 512 8 1260000 8000000
5:inner_lru_hash_map_perf pre-alloc 1628380 events per sec
4:inner_lru_hash_map_perf pre-alloc 1626396 events per sec
3:inner_lru_hash_map_perf pre-alloc 1626144 events per sec
6:inner_lru_hash_map_perf pre-alloc 1621657 events per sec
2:inner_lru_hash_map_perf pre-alloc 1621534 events per sec
1:inner_lru_hash_map_perf pre-alloc 1620292 events per sec
7:inner_lru_hash_map_perf pre-alloc 1613305 events per sec
0:inner_lru_hash_map_perf pre-alloc 1239150 events per sec  #&lt;&lt;&lt;

After specifying numa node:
&gt;# taskset -c 10 ./map_perf_test 512 8 1260000 8000000
5:inner_lru_hash_map_perf pre-alloc 1629627 events per sec
3:inner_lru_hash_map_perf pre-alloc 1628057 events per sec
1:inner_lru_hash_map_perf pre-alloc 1623054 events per sec
6:inner_lru_hash_map_perf pre-alloc 1616033 events per sec
2:inner_lru_hash_map_perf pre-alloc 1614630 events per sec
4:inner_lru_hash_map_perf pre-alloc 1612651 events per sec
7:inner_lru_hash_map_perf pre-alloc 1609337 events per sec
0:inner_lru_hash_map_perf pre-alloc 1619340 events per sec #&lt;&lt;&lt;

This patch adds one field, numa_node, to the bpf_attr.  Since numa node 0
is a valid node, a new flag BPF_F_NUMA_NODE is also added.  The numa_node
field is honored if and only if the BPF_F_NUMA_NODE flag is set.

Numa node selection is not supported for percpu map.

This patch does not change all the kmalloc.  F.e.
'htab = kzalloc()' is not changed since the object
is small enough to stay in the cache.

Signed-off-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Alexei Starovoitov &lt;ast@fb.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: Add syscall lookup support for fd array and htab</title>
<updated>2017-06-29T17:13:25+00:00</updated>
<author>
<name>Martin KaFai Lau</name>
<email>kafai@fb.com</email>
</author>
<published>2017-06-28T06:08:34+00:00</published>
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<id>urn:sha1:14dc6f04f49dc12614d7e90928b495b8d73cd471</id>
<content type='text'>
This patch allows userspace to do BPF_MAP_LOOKUP_ELEM on
BPF_MAP_TYPE_PROG_ARRAY,
BPF_MAP_TYPE_ARRAY_OF_MAPS and
BPF_MAP_TYPE_HASH_OF_MAPS.

The lookup returns a prog-id or map-id to the userspace.
The userspace can then use the BPF_PROG_GET_FD_BY_ID
or BPF_MAP_GET_FD_BY_ID to get a fd.

Signed-off-by: Martin KaFai Lau &lt;kafai@fb.com&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>perf, bpf: Add BPF support to all perf_event types</title>
<updated>2017-06-05T01:58:01+00:00</updated>
<author>
<name>Alexei Starovoitov</name>
<email>ast@fb.com</email>
</author>
<published>2017-06-03T04:03:52+00:00</published>
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<id>urn:sha1:f91840a32deef5cb1bf73338bc5010f843b01426</id>
<content type='text'>
Allow BPF_PROG_TYPE_PERF_EVENT program types to attach to all
perf_event types, including HW_CACHE, RAW, and dynamic pmu events.
Only tracepoint/kprobe events are treated differently which require
BPF_PROG_TYPE_TRACEPOINT/BPF_PROG_TYPE_KPROBE program types accordingly.

Also add support for reading all event counters using
bpf_perf_event_read() helper.

Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: fix wrong exposure of map_flags into fdinfo for lpm</title>
<updated>2017-05-25T17:44:28+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2017-05-24T23:05:08+00:00</published>
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<id>urn:sha1:a316338cb71a3260201490e615f2f6d5c0d8fb2c</id>
<content type='text'>
trie_alloc() always needs to have BPF_F_NO_PREALLOC passed in via
attr-&gt;map_flags, since it does not support preallocation yet. We
check the flag, but we never copy the flag into trie-&gt;map.map_flags,
which is later on exposed into fdinfo and used by loaders such as
iproute2. Latter uses this in bpf_map_selfcheck_pinned() to test
whether a pinned map has the same spec as the one from the BPF obj
file and if not, bails out, which is currently the case for lpm
since it exposes always 0 as flags.

Also copy over flags in array_map_alloc() and stack_map_alloc().
They always have to be 0 right now, but we should make sure to not
miss to copy them over at a later point in time when we add actual
flags for them to use.

Fixes: b95a5c4db09b ("bpf: add a longest prefix match trie map implementation")
Reported-by: Jarno Rajahalme &lt;jarno@covalent.io&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>bpf: map_get_next_key to return first key on NULL</title>
<updated>2017-04-25T15:57:45+00:00</updated>
<author>
<name>Teng Qin</name>
<email>qinteng@fb.com</email>
</author>
<published>2017-04-25T02:00:37+00:00</published>
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<id>urn:sha1:8fe45924387be6b5c1be59a7eb330790c61d5d10</id>
<content type='text'>
When iterating through a map, we need to find a key that does not exist
in the map so map_get_next_key will give us the first key of the map.
This often requires a lot of guessing in production systems.

This patch makes map_get_next_key return the first key when the key
pointer in the parameter is NULL.

Signed-off-by: Teng Qin &lt;qinteng@fb.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Acked-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
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