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authorAbel Wu <wuyun.abel@bytedance.com>2023-08-16 17:12:22 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-08-23 17:52:35 +0200
commit06b8f06f93024863e5519b7aca500a952ced44cc (patch)
treef82c2ce55bbc1f5bbb7e05e06a7a3976d5566935 /include
parent3d820924c00ceeabdea2b9414a1fbd7d30727a2f (diff)
downloadlinux-06b8f06f93024863e5519b7aca500a952ced44cc.tar.gz
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>
Diffstat (limited to 'include')
-rw-r--r--include/net/sock.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 1bbdddcf6154..699408944952 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1445,6 +1445,12 @@ 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)