From: Abel Wu wuyun.abel@bytedance.com
[ Upstream commit 2d0c88e84e483982067a82073f6125490ddf3614 ]
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 Acked-by: Shakeel Butt shakeelb@google.com Link: https://lore.kernel.org/r/20230816091226.1542-1-wuyun.abel@bytedance.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/sock.h | 6 ++++++ net/core/sock.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/net/sock.h b/include/net/sock.h index 1fb5c535537c1..665e388593752 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1346,6 +1346,12 @@ 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 (!sk->sk_prot->memory_pressure) diff --git a/net/core/sock.c b/net/core/sock.c index 98f4b4a80de42..742356cfd07c4 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2724,7 +2724,7 @@ 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); }