Commit 2f7e4ab2 authored by Yafang Shao's avatar Yafang Shao Committed by Alexei Starovoitov
Browse files

bpf: ringbuf memory usage 



A new helper ringbuf_map_mem_usage() is introduced to calculate ringbuf
memory usage.

The result as follows,
- before
15: ringbuf  name count_map  flags 0x0
        key 0B  value 0B  max_entries 65536  memlock 0B

- after
15: ringbuf  name count_map  flags 0x0
        key 0B  value 0B  max_entries 65536  memlock 78424B

Signed-off-by: default avatarYafang Shao <laoar.shao@gmail.com>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230305124615.12358-8-laoar.shao@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 2e89caf0

kernel/bpf/ringbuf.c

+19 −1
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
	(offsetof(struct bpf_ringbuf, consumer_pos) >> PAGE_SHIFT)

/* consumer page and producer page */

#define RINGBUF_POS_PAGES 2

#define RINGBUF_NR_META_PAGES (RINGBUF_PGOFF + RINGBUF_POS_PAGES)



#define RINGBUF_MAX_RECORD_SZ (UINT_MAX/4)
@@ -96,7 +97,7 @@ static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) 
{

	const gfp_t flags = GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL |

			    __GFP_NOWARN | __GFP_ZERO;

	int nr_meta_pages = RINGBUF_PGOFF + RINGBUF_POS_PAGES;

	int nr_meta_pages = RINGBUF_NR_META_PAGES;

	int nr_data_pages = data_sz >> PAGE_SHIFT;

	int nr_pages = nr_meta_pages + nr_data_pages;

	struct page **pages, *page;
@@ -336,6 +337,21 @@ static __poll_t ringbuf_map_poll_user(struct bpf_map *map, struct file *filp, 
	return 0;

}



static u64 ringbuf_map_mem_usage(const struct bpf_map *map)

{

	struct bpf_ringbuf *rb;

	int nr_data_pages;

	int nr_meta_pages;

	u64 usage = sizeof(struct bpf_ringbuf_map);



	rb = container_of(map, struct bpf_ringbuf_map, map)->rb;

	usage += (u64)rb->nr_pages << PAGE_SHIFT;

	nr_meta_pages = RINGBUF_NR_META_PAGES;

	nr_data_pages = map->max_entries >> PAGE_SHIFT;

	usage += (nr_meta_pages + 2 * nr_data_pages) * sizeof(struct page *);

	return usage;

}



BTF_ID_LIST_SINGLE(ringbuf_map_btf_ids, struct, bpf_ringbuf_map)

const struct bpf_map_ops ringbuf_map_ops = {

	.map_meta_equal = bpf_map_meta_equal,
@@ -347,6 +363,7 @@ const struct bpf_map_ops ringbuf_map_ops = { 
	.map_update_elem = ringbuf_map_update_elem,

	.map_delete_elem = ringbuf_map_delete_elem,

	.map_get_next_key = ringbuf_map_get_next_key,

	.map_mem_usage = ringbuf_map_mem_usage,

	.map_btf_id = &ringbuf_map_btf_ids[0],

};
@@ -361,6 +378,7 @@ const struct bpf_map_ops user_ringbuf_map_ops = { 
	.map_update_elem = ringbuf_map_update_elem,

	.map_delete_elem = ringbuf_map_delete_elem,

	.map_get_next_key = ringbuf_map_get_next_key,

	.map_mem_usage = ringbuf_map_mem_usage,

	.map_btf_id = &user_ringbuf_map_btf_ids[0],

};