linux-kernel - [PATCH v2 4/4] sock: Remove redundant cond of memcg pressure

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Message-Id: <20230522070122.6727-5-wuyun.abel@bytedance.com>
Date:   Mon, 22 May 2023 15:01:22 +0800
From:   Abel Wu <wuyun.abel@...edance.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     Glauber Costa <glommer@...allels.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Abel Wu <wuyun.abel@...edance.com>
Subject: [PATCH v2 4/4] sock: Remove redundant cond of memcg pressure

Now with the preivous patch, __sk_mem_raise_allocated() considers
the memory pressure of both global and the socket's memcg on a func-
wide level, making the condition of memcg's pressure in question
redundant.

Signed-off-by: Abel Wu <wuyun.abel@...edance.com>
---
 net/core/sock.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 7641d64293af..baccbb58a11a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3029,9 +3029,14 @@ int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
 	if (sk_has_memory_pressure(sk)) {
 		u64 alloc;
 
-		if (!sk_under_memory_pressure(sk))
+		if (!sk_under_global_memory_pressure(sk))
 			return 1;
 		alloc = sk_sockets_allocated_read_positive(sk);
+		/*
+		 * If under global pressure, allow the sockets that are below
+		 * average memory usage to raise, trying to be fair among all
+		 * the sockets under global constrains.
+		 */
 		if (sk_prot_mem_limits(sk, 2) > alloc *
 		    sk_mem_pages(sk->sk_wmem_queued +
 				 atomic_read(&sk->sk_rmem_alloc) +
-- 
2.37.3