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authorAbel Wu <wuyun.abel@bytedance.com>2023-08-16 17:12:22 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-08-26 14:23:35 +0200
commit5fc4fd3f3eb8056859dd396e7de349b4da560f0e (patch)
tree6d003134c91a8e3fe5eec558f6961808fd82d78c
parentfc3d82d295d1f65543d322af84a88f898fbade87 (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 93a6717213ae..6b12b62417e0 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1381,6 +1381,12 @@ 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 1f9401d757cb..ae1e9e2b8255 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2880,7 +2880,7 @@ 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);
}