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bpf: ringbuf memory usage

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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: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230305124615.12358-8-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yafang Shao 2023-03-05 12:46:04 +00:00 committed by Alexei Starovoitov
parent 2e89caf055
commit 2f7e4ab2ca
1 changed files with 19 additions and 1 deletions
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20
kernel/bpf/ringbuf.c
View File

@ -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],
};