* [Patch bpf-next] sock_map: include sk_psock memory overhead too
@ 2023-03-26 22:16 Cong Wang
2023-03-27 3:48 ` Yafang Shao
0 siblings, 1 reply; 4+ messages in thread
From: Cong Wang @ 2023-03-26 22:16 UTC (permalink / raw)
To: netdev; +Cc: bpf, Cong Wang, Yafang Shao, Jakub Sitnicki, John Fastabend
From: Cong Wang <cong.wang@bytedance.com>
When a socket is added to a sockmap, sk_psock is allocated too as its
sk_user_data, therefore it should be consider as an overhead of sockmap
memory usage.
Before this patch:
1: sockmap flags 0x0
key 4B value 4B max_entries 2 memlock 656B
pids echo-sockmap(549)
After this patch:
9: sockmap flags 0x0
key 4B value 4B max_entries 2 memlock 1824B
pids echo-sockmap(568)
Fixes: 73d2c61919e9 ("bpf, net: sock_map memory usage")
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
net/core/sock_map.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 7c189c2e2fbf..22197e565ece 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -799,9 +799,17 @@ static void sock_map_fini_seq_private(void *priv_data)
static u64 sock_map_mem_usage(const struct bpf_map *map)
{
+ struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
u64 usage = sizeof(struct bpf_stab);
+ int i;
usage += (u64)map->max_entries * sizeof(struct sock *);
+
+ for (i = 0; i < stab->map.max_entries; i++) {
+ if (stab->sks[i])
+ usage += sizeof(struct sk_psock);
+ }
+
return usage;
}
@@ -1412,7 +1420,7 @@ static u64 sock_hash_mem_usage(const struct bpf_map *map)
u64 usage = sizeof(*htab);
usage += htab->buckets_num * sizeof(struct bpf_shtab_bucket);
- usage += atomic_read(&htab->count) * (u64)htab->elem_size;
+ usage += atomic_read(&htab->count) * ((u64)htab->elem_size + sizeof(struct sk_psock));
return usage;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Patch bpf-next] sock_map: include sk_psock memory overhead too
2023-03-26 22:16 [Patch bpf-next] sock_map: include sk_psock memory overhead too Cong Wang
@ 2023-03-27 3:48 ` Yafang Shao
2023-04-01 1:09 ` John Fastabend
0 siblings, 1 reply; 4+ messages in thread
From: Yafang Shao @ 2023-03-27 3:48 UTC (permalink / raw)
To: Cong Wang; +Cc: netdev, bpf, Cong Wang, Jakub Sitnicki, John Fastabend
On Mon, Mar 27, 2023 at 6:16 AM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>
> From: Cong Wang <cong.wang@bytedance.com>
>
> When a socket is added to a sockmap, sk_psock is allocated too as its
> sk_user_data, therefore it should be consider as an overhead of sockmap
> memory usage.
>
> Before this patch:
>
> 1: sockmap flags 0x0
> key 4B value 4B max_entries 2 memlock 656B
> pids echo-sockmap(549)
>
> After this patch:
>
> 9: sockmap flags 0x0
> key 4B value 4B max_entries 2 memlock 1824B
> pids echo-sockmap(568)
>
> Fixes: 73d2c61919e9 ("bpf, net: sock_map memory usage")
> Cc: Yafang Shao <laoar.shao@gmail.com>
> Cc: Jakub Sitnicki <jakub@cloudflare.com>
> Cc: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Cong Wang <cong.wang@bytedance.com>
> ---
> net/core/sock_map.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> index 7c189c2e2fbf..22197e565ece 100644
> --- a/net/core/sock_map.c
> +++ b/net/core/sock_map.c
> @@ -799,9 +799,17 @@ static void sock_map_fini_seq_private(void *priv_data)
>
> static u64 sock_map_mem_usage(const struct bpf_map *map)
> {
> + struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
> u64 usage = sizeof(struct bpf_stab);
> + int i;
>
> usage += (u64)map->max_entries * sizeof(struct sock *);
> +
> + for (i = 0; i < stab->map.max_entries; i++) {
Although it adds a for-loop, the operation below is quite light. So it
looks good to me.
> + if (stab->sks[i])
Nit, stab->sks[i] can be modified in the delete path in parallel, so
there should be a READ_ONCE() here.
> + usage += sizeof(struct sk_psock);
> + }
> +
> return usage;
> }
>
> @@ -1412,7 +1420,7 @@ static u64 sock_hash_mem_usage(const struct bpf_map *map)
> u64 usage = sizeof(*htab);
>
> usage += htab->buckets_num * sizeof(struct bpf_shtab_bucket);
> - usage += atomic_read(&htab->count) * (u64)htab->elem_size;
> + usage += atomic_read(&htab->count) * ((u64)htab->elem_size + sizeof(struct sk_psock));
> return usage;
> }
>
> --
> 2.34.1
>
--
Regards
Yafang
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch bpf-next] sock_map: include sk_psock memory overhead too
2023-03-27 3:48 ` Yafang Shao
@ 2023-04-01 1:09 ` John Fastabend
2023-04-02 10:41 ` Yafang Shao
0 siblings, 1 reply; 4+ messages in thread
From: John Fastabend @ 2023-04-01 1:09 UTC (permalink / raw)
To: Yafang Shao, Cong Wang
Cc: netdev, bpf, Cong Wang, Jakub Sitnicki, John Fastabend
Yafang Shao wrote:
> On Mon, Mar 27, 2023 at 6:16 AM Cong Wang <xiyou.wangcong@gmail.com> wrote:
> >
> > From: Cong Wang <cong.wang@bytedance.com>
> >
> > When a socket is added to a sockmap, sk_psock is allocated too as its
> > sk_user_data, therefore it should be consider as an overhead of sockmap
> > memory usage.
> >
> > Before this patch:
> >
> > 1: sockmap flags 0x0
> > key 4B value 4B max_entries 2 memlock 656B
> > pids echo-sockmap(549)
> >
> > After this patch:
> >
> > 9: sockmap flags 0x0
> > key 4B value 4B max_entries 2 memlock 1824B
> > pids echo-sockmap(568)
> >
> > Fixes: 73d2c61919e9 ("bpf, net: sock_map memory usage")
> > Cc: Yafang Shao <laoar.shao@gmail.com>
> > Cc: Jakub Sitnicki <jakub@cloudflare.com>
> > Cc: John Fastabend <john.fastabend@gmail.com>
> > Signed-off-by: Cong Wang <cong.wang@bytedance.com>
> > ---
> > net/core/sock_map.c | 10 +++++++++-
> > 1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> > index 7c189c2e2fbf..22197e565ece 100644
> > --- a/net/core/sock_map.c
> > +++ b/net/core/sock_map.c
> > @@ -799,9 +799,17 @@ static void sock_map_fini_seq_private(void *priv_data)
> >
> > static u64 sock_map_mem_usage(const struct bpf_map *map)
> > {
> > + struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
> > u64 usage = sizeof(struct bpf_stab);
> > + int i;
> >
> > usage += (u64)map->max_entries * sizeof(struct sock *);
> > +
> > + for (i = 0; i < stab->map.max_entries; i++) {
>
> Although it adds a for-loop, the operation below is quite light. So it
> looks good to me.
We could track a count from update to avoid the loop?
>
> > + if (stab->sks[i])
>
> Nit, stab->sks[i] can be modified in the delete path in parallel, so
> there should be a READ_ONCE() here.
>
> > + usage += sizeof(struct sk_psock);
> > + }
> > +
> > return usage;
> > }
> >
> > @@ -1412,7 +1420,7 @@ static u64 sock_hash_mem_usage(const struct bpf_map *map)
> > u64 usage = sizeof(*htab);
> >
> > usage += htab->buckets_num * sizeof(struct bpf_shtab_bucket);
> > - usage += atomic_read(&htab->count) * (u64)htab->elem_size;
> > + usage += atomic_read(&htab->count) * ((u64)htab->elem_size + sizeof(struct sk_psock));
> > return usage;
> > }
> >
> > --
> > 2.34.1
> >
>
>
> --
> Regards
> Yafang
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch bpf-next] sock_map: include sk_psock memory overhead too
2023-04-01 1:09 ` John Fastabend
@ 2023-04-02 10:41 ` Yafang Shao
0 siblings, 0 replies; 4+ messages in thread
From: Yafang Shao @ 2023-04-02 10:41 UTC (permalink / raw)
To: John Fastabend; +Cc: Cong Wang, netdev, bpf, Cong Wang, Jakub Sitnicki
On Sat, Apr 1, 2023 at 9:09 AM John Fastabend <john.fastabend@gmail.com> wrote:
>
> Yafang Shao wrote:
> > On Mon, Mar 27, 2023 at 6:16 AM Cong Wang <xiyou.wangcong@gmail.com> wrote:
> > >
> > > From: Cong Wang <cong.wang@bytedance.com>
> > >
> > > When a socket is added to a sockmap, sk_psock is allocated too as its
> > > sk_user_data, therefore it should be consider as an overhead of sockmap
> > > memory usage.
> > >
> > > Before this patch:
> > >
> > > 1: sockmap flags 0x0
> > > key 4B value 4B max_entries 2 memlock 656B
> > > pids echo-sockmap(549)
> > >
> > > After this patch:
> > >
> > > 9: sockmap flags 0x0
> > > key 4B value 4B max_entries 2 memlock 1824B
> > > pids echo-sockmap(568)
> > >
> > > Fixes: 73d2c61919e9 ("bpf, net: sock_map memory usage")
> > > Cc: Yafang Shao <laoar.shao@gmail.com>
> > > Cc: Jakub Sitnicki <jakub@cloudflare.com>
> > > Cc: John Fastabend <john.fastabend@gmail.com>
> > > Signed-off-by: Cong Wang <cong.wang@bytedance.com>
> > > ---
> > > net/core/sock_map.c | 10 +++++++++-
> > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> > > index 7c189c2e2fbf..22197e565ece 100644
> > > --- a/net/core/sock_map.c
> > > +++ b/net/core/sock_map.c
> > > @@ -799,9 +799,17 @@ static void sock_map_fini_seq_private(void *priv_data)
> > >
> > > static u64 sock_map_mem_usage(const struct bpf_map *map)
> > > {
> > > + struct bpf_stab *stab = container_of(map, struct bpf_stab, map);
> > > u64 usage = sizeof(struct bpf_stab);
> > > + int i;
> > >
> > > usage += (u64)map->max_entries * sizeof(struct sock *);
> > > +
> > > + for (i = 0; i < stab->map.max_entries; i++) {
> >
> > Although it adds a for-loop, the operation below is quite light. So it
> > looks good to me.
>
> We could track a count from update to avoid the loop?
>
I prefer adding a count into struct bpf_stab. We can also get the
number of socks easily with this new count, and it should be
acceptable to modify this count in the update/delete paths.
--
Regards
Yafang
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-03-26 22:16 [Patch bpf-next] sock_map: include sk_psock memory overhead too Cong Wang
2023-03-27 3:48 ` Yafang Shao
2023-04-01 1:09 ` John Fastabend
2023-04-02 10:41 ` Yafang Shao
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