bpf: add bpffs pretty print for percpu arraymap/hash/lru_hash

Added bpffs pretty print for percpu arraymap, percpu hashmap
and percpu lru hashmap.

For each map <key, value> pair, the format is:
   <key_value>: {
	cpu0: <value_on_cpu0>
	cpu1: <value_on_cpu1>
	...
	cpun: <value_on_cpun>
   }

For example, on my VM, there are 4 cpus, and
for test_btf test in the next patch:
   cat /sys/fs/bpf/pprint_test_percpu_hash

You may get:
   ...
   43602: {
	cpu0: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO}
	cpu1: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO}
	cpu2: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO}
	cpu3: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO}
   }
   72847: {
	cpu0: {72847,0,-72847,0x3,0x11c8f,0x3,{72847|[143,28,1,0,0,0,0,0]},ENUM_THREE}
	cpu1: {72847,0,-72847,0x3,0x11c8f,0x3,{72847|[143,28,1,0,0,0,0,0]},ENUM_THREE}
	cpu2: {72847,0,-72847,0x3,0x11c8f,0x3,{72847|[143,28,1,0,0,0,0,0]},ENUM_THREE}
	cpu3: {72847,0,-72847,0x3,0x11c8f,0x3,{72847|[143,28,1,0,0,0,0,0]},ENUM_THREE}
   }
   ...

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 0c17aab3ce5f8c03867f57ca402d985f669fca11..f9d24121be991ccd80d64b4224b5518b5c6bfda2 100644 (file)
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -358,6 +358,29 @@ static void array_map_seq_show_elem(struct bpf_map *map, void *key,
        rcu_read_unlock();
 }
 
+static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
+                                          struct seq_file *m)
+{
+       struct bpf_array *array = container_of(map, struct bpf_array, map);
+       u32 index = *(u32 *)key;
+       void __percpu *pptr;
+       int cpu;
+
+       rcu_read_lock();
+
+       seq_printf(m, "%u: {\n", *(u32 *)key);
+       pptr = array->pptrs[index & array->index_mask];
+       for_each_possible_cpu(cpu) {
+               seq_printf(m, "\tcpu%d: ", cpu);
+               btf_type_seq_show(map->btf, map->btf_value_type_id,
+                                 per_cpu_ptr(pptr, cpu), m);
+               seq_puts(m, "\n");
+       }
+       seq_puts(m, "}\n");
+
+       rcu_read_unlock();
+}
+
 static int array_map_check_btf(const struct bpf_map *map,
                               const struct btf_type *key_type,
                               const struct btf_type *value_type)
@@ -398,6 +421,7 @@ const struct bpf_map_ops percpu_array_map_ops = {
        .map_lookup_elem = percpu_array_map_lookup_elem,
        .map_update_elem = array_map_update_elem,
        .map_delete_elem = array_map_delete_elem,
+       .map_seq_show_elem = percpu_array_map_seq_show_elem,
        .map_check_btf = array_map_check_btf,
 };
 

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 03cc59ee9c9536b885d605027af093c3dd0634ee..2c1790288138771a5d527ca5507fec7c9aca16f6 100644 (file)
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -1285,6 +1285,35 @@ int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
        return ret;
 }
 
+static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key,
+                                         struct seq_file *m)
+{
+       struct htab_elem *l;
+       void __percpu *pptr;
+       int cpu;
+
+       rcu_read_lock();
+
+       l = __htab_map_lookup_elem(map, key);
+       if (!l) {
+               rcu_read_unlock();
+               return;
+       }
+
+       btf_type_seq_show(map->btf, map->btf_key_type_id, key, m);
+       seq_puts(m, ": {\n");
+       pptr = htab_elem_get_ptr(l, map->key_size);
+       for_each_possible_cpu(cpu) {
+               seq_printf(m, "\tcpu%d: ", cpu);
+               btf_type_seq_show(map->btf, map->btf_value_type_id,
+                                 per_cpu_ptr(pptr, cpu), m);
+               seq_puts(m, "\n");
+       }
+       seq_puts(m, "}\n");
+
+       rcu_read_unlock();
+}
+
 const struct bpf_map_ops htab_percpu_map_ops = {
        .map_alloc_check = htab_map_alloc_check,
        .map_alloc = htab_map_alloc,
@@ -1293,6 +1322,7 @@ const struct bpf_map_ops htab_percpu_map_ops = {
        .map_lookup_elem = htab_percpu_map_lookup_elem,
        .map_update_elem = htab_percpu_map_update_elem,
        .map_delete_elem = htab_map_delete_elem,
+       .map_seq_show_elem = htab_percpu_map_seq_show_elem,
 };
 
 const struct bpf_map_ops htab_lru_percpu_map_ops = {
@@ -1303,6 +1333,7 @@ const struct bpf_map_ops htab_lru_percpu_map_ops = {
        .map_lookup_elem = htab_lru_percpu_map_lookup_elem,
        .map_update_elem = htab_lru_percpu_map_update_elem,
        .map_delete_elem = htab_lru_map_delete_elem,
+       .map_seq_show_elem = htab_percpu_map_seq_show_elem,
 };
 
 static int fd_htab_map_alloc_check(union bpf_attr *attr)