| Message ID | 20230522070122.6727-3-wuyun.abel@bytedance.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | sock: Improve condition on sockmem pressure | expand |
On Mon, May 22, 2023 at 03:01:20PM +0800, Abel Wu wrote: > The status of global socket memory pressure is updated when: > > a) __sk_mem_raise_allocated(): > > enter: sk_memory_allocated(sk) > sysctl_mem[1] > leave: sk_memory_allocated(sk) <= sysctl_mem[0] > > b) __sk_mem_reduce_allocated(): > > leave: sk_under_memory_pressure(sk) && > sk_memory_allocated(sk) < sysctl_mem[0] > > So the conditions of leaving global pressure are inconstant, which > may lead to the situation that one pressured net-memcg prevents the > global pressure from being cleared when there is indeed no global > pressure, thus the global constrains are still in effect unexpectedly > on the other sockets. > > This patch fixes this by ignoring the net-memcg's pressure when > deciding whether should leave global memory pressure. > > Fixes: e1aab161e013 ("socket: initial cgroup code") really pedantic nit: Fixes: e1aab161e013 ("socket: initial cgroup code.") > Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> ...
diff --git a/include/net/sock.h b/include/net/sock.h index c73d9bad7ac7..bf930d4db7f0 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1409,14 +1409,19 @@ static inline bool sk_has_memory_pressure(const struct sock *sk) return sk->sk_prot->memory_pressure != NULL; } +static inline bool sk_under_global_memory_pressure(const struct sock *sk) +{ + return sk->sk_prot->memory_pressure && + *sk->sk_prot->memory_pressure; +} + static inline bool sk_under_memory_pressure(const struct sock *sk) { if (mem_cgroup_sockets_enabled && sk->sk_memcg && mem_cgroup_under_socket_pressure(sk->sk_memcg)) return true; - return sk->sk_prot->memory_pressure && - *sk->sk_prot->memory_pressure; + return sk_under_global_memory_pressure(sk); } static inline long diff --git a/net/core/sock.c b/net/core/sock.c index 5440e67bcfe3..801df091e37a 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3095,7 +3095,7 @@ void __sk_mem_reduce_allocated(struct sock *sk, int amount) if (mem_cgroup_sockets_enabled && sk->sk_memcg) mem_cgroup_uncharge_skmem(sk->sk_memcg, amount); - if (sk_under_memory_pressure(sk) && + if (sk_under_global_memory_pressure(sk) && (sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0))) sk_leave_memory_pressure(sk); }
The status of global socket memory pressure is updated when: a) __sk_mem_raise_allocated(): enter: sk_memory_allocated(sk) > sysctl_mem[1] leave: sk_memory_allocated(sk) <= sysctl_mem[0] b) __sk_mem_reduce_allocated(): leave: sk_under_memory_pressure(sk) && sk_memory_allocated(sk) < sysctl_mem[0] So the conditions of leaving global pressure are inconstant, which may lead to the situation that one pressured net-memcg prevents the global pressure from being cleared when there is indeed no global pressure, thus the global constrains are still in effect unexpectedly on the other sockets. This patch fixes this by ignoring the net-memcg's pressure when deciding whether should leave global memory pressure. Fixes: e1aab161e013 ("socket: initial cgroup code") Signed-off-by: Abel Wu <wuyun.abel@bytedance.com> --- include/net/sock.h | 9 +++++++-- net/core/sock.c | 2 +- 2 files changed, 8 insertions(+), 3 deletions(-)