[PATCH bpf-next v4 14/18] bpf, net: bpf_local_storage memory usage

[Yafang Shao <laoar.shao@gmail.com>]

A new helper is introduced into bpf_local_storage map to calculate the
memory usage. This helper is also used by other maps like
bpf_cgrp_storage, bpf_inode_storage, bpf_task_storage and etc.

Note that currently the dynamically allocated storage elements are not
counted in the usage, since it will take extra runtime overhead in the
elements update or delete path. So let's put it aside now, and implement
it in the future when someone really need it.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 include/linux/bpf_local_storage.h |  1 +
 kernel/bpf/bpf_cgrp_storage.c     |  1 +
 kernel/bpf/bpf_inode_storage.c    |  1 +
 kernel/bpf/bpf_local_storage.c    | 10 ++++++++++
 kernel/bpf/bpf_task_storage.c     |  1 +
 net/core/bpf_sk_storage.c         |  1 +
 6 files changed, 15 insertions(+)

diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 6d37a40..d934248 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -164,5 +164,6 @@ struct bpf_local_storage_data *
 			 void *value, u64 map_flags, gfp_t gfp_flags);
 
 void bpf_local_storage_free_rcu(struct rcu_head *rcu);
+u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map);
 
 #endif /* _BPF_LOCAL_STORAGE_H */
diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c
index 6cdf6d9..9ae07ae 100644
--- a/kernel/bpf/bpf_cgrp_storage.c
+++ b/kernel/bpf/bpf_cgrp_storage.c
@@ -221,6 +221,7 @@ static void cgroup_storage_map_free(struct bpf_map *map)
 	.map_update_elem = bpf_cgrp_storage_update_elem,
 	.map_delete_elem = bpf_cgrp_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
+	.map_mem_usage = bpf_local_storage_map_mem_usage,
 	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_owner_storage_ptr = cgroup_storage_ptr,
 };
diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index 05f4c66..43e2619c 100644
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -223,6 +223,7 @@ static void inode_storage_map_free(struct bpf_map *map)
 	.map_update_elem = bpf_fd_inode_storage_update_elem,
 	.map_delete_elem = bpf_fd_inode_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
+	.map_mem_usage = bpf_local_storage_map_mem_usage,
 	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_owner_storage_ptr = inode_storage_ptr,
 };
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 3d32039..d3ba3f2 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -685,6 +685,16 @@ bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage)
 	return free_storage;
 }
 
+u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map)
+{
+	struct bpf_local_storage_map *smap = (struct bpf_local_storage_map *)map;
+	u64 usage = sizeof(*smap);
+
+	/* The dynamically callocated selems are not counted currently. */
+	usage += sizeof(*smap->buckets) * (1ULL << smap->bucket_log);
+	return usage;
+}
+
 struct bpf_map *
 bpf_local_storage_map_alloc(union bpf_attr *attr,
 			    struct bpf_local_storage_cache *cache)
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index 1e48605..20f9422 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -335,6 +335,7 @@ static void task_storage_map_free(struct bpf_map *map)
 	.map_update_elem = bpf_pid_task_storage_update_elem,
 	.map_delete_elem = bpf_pid_task_storage_delete_elem,
 	.map_check_btf = bpf_local_storage_map_check_btf,
+	.map_mem_usage = bpf_local_storage_map_mem_usage,
 	.map_btf_id = &bpf_local_storage_map_btf_id[0],
 	.map_owner_storage_ptr = task_storage_ptr,
 };
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index bb378c3..7a36353 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -324,6 +324,7 @@ static void bpf_sk_storage_uncharge(struct bpf_local_storage_map *smap,
 	.map_local_storage_charge = bpf_sk_storage_charge,
 	.map_local_storage_uncharge = bpf_sk_storage_uncharge,
 	.map_owner_storage_ptr = bpf_sk_storage_ptr,
+	.map_mem_usage = bpf_local_storage_map_mem_usage,
 };
 
 const struct bpf_func_proto bpf_sk_storage_get_proto = {
-- 
1.8.3.1