bpf: Allow selecting numa node during map creation

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 ]

># 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  #<<<

After specifying numa node:
># 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 #<<<

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 <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 3 deletions

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 39de541fbcdc..78b2bb9370ac 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -443,7 +443,9 @@ static struct smap_psock *smap_init_psock(struct sock *sock,
 {
         struct smap_psock *psock;
 
-        psock = kzalloc(sizeof(struct smap_psock), GFP_ATOMIC | __GFP_NOWARN);
+        psock = kzalloc_node(sizeof(struct smap_psock),
+                             GFP_ATOMIC | __GFP_NOWARN,
+                             stab->map.numa_node);
         if (!psock)
                 return ERR_PTR(-ENOMEM);
 
@@ -465,7 +467,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
 
         /* check sanity of attributes */
         if (attr->max_entries == 0 || attr->key_size != 4 ||
-            attr->value_size != 4 || attr->map_flags)
+            attr->value_size != 4 || attr->map_flags & ~BPF_F_NUMA_NODE)
                 return ERR_PTR(-EINVAL);
 
         if (attr->value_size > KMALLOC_MAX_SIZE)
@@ -481,6 +483,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
         stab->map.value_size = attr->value_size;
         stab->map.max_entries = attr->max_entries;
         stab->map.map_flags = attr->map_flags;
+        stab->map.numa_node = bpf_map_attr_numa_node(attr);
 
         /* make sure page count doesn't overflow */
         cost = (u64) stab->map.max_entries * sizeof(struct sock *);
@@ -495,7 +498,8 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
                 goto free_stab;
 
         stab->sock_map = bpf_map_area_alloc(stab->map.max_entries *
-                                            sizeof(struct sock *));
+                                            sizeof(struct sock *),
+                                            stab->map.numa_node);
         if (!stab->sock_map)
                 goto free_stab;