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authorAbel Wu <wuyun.abel@bytedance.com>2023-08-16 17:12:22 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-08-30 16:35:12 +0200
commitb6ef156a1a190ee7d0d24e28cf858e099dbf785c (patch)
tree5a2bfa53f8349b3c75b85d5687a4a4aa6684cf56
parent2d7d973da4827f8e1a4145ddceb3eccfe2e3082a (diff)
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sock: Fix misuse of sk_under_memory_pressure()
[ 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>
-rw-r--r--include/net/sock.h6
-rw-r--r--net/core/sock.c2
2 files changed, 7 insertions, 1 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index def9dc1ddda1..1937deba0849 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1211,6 +1211,12 @@ 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 0ff80718f194..a7a0bc9c2a9f 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2459,7 +2459,7 @@ 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);
}