5.4-stable review patch. If anyone has any objections, please let me know.
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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 ee8630d6abc16..61f5872aac24f 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1274,6 +1274,12 @@ 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 636427d400d7f..69b4158a29f74 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2631,7 +2631,7 @@ 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); }