linux-kernel - [PATCH v2 3/4] sock: Consider memcg pressure when raising sockmem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230522070122.6727-4-wuyun.abel@bytedance.com>
Date:   Mon, 22 May 2023 15:01:21 +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 3/4] sock: Consider memcg pressure when raising sockmem

For now __sk_mem_raise_allocated() mainly considers global socket
memory pressure and allows to raise if no global pressure observed,
including the sockets whose memcgs are in pressure, which might
result in longer memcg memstall.

So take net-memcg's pressure into consideration when allocating
socket memory to alleviate long tail latencies.

Signed-off-by: Abel Wu <wuyun.abel@...edance.com>
---
 net/core/sock.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index 801df091e37a..7641d64293af 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2977,21 +2977,30 @@ int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
 {
 	bool memcg_charge = mem_cgroup_sockets_enabled && sk->sk_memcg;
 	struct proto *prot = sk->sk_prot;
-	bool charged = true;
+	bool charged = true, pressured = false;
 	long allocated;
 
 	sk_memory_allocated_add(sk, amt);
 	allocated = sk_memory_allocated(sk);
-	if (memcg_charge &&
-	    !(charged = mem_cgroup_charge_skmem(sk->sk_memcg, amt,
-						gfp_memcg_charge())))
-		goto suppress_allocation;
+
+	if (memcg_charge) {
+		charged = mem_cgroup_charge_skmem(sk->sk_memcg, amt,
+						  gfp_memcg_charge());
+		if (!charged)
+			goto suppress_allocation;
+		if (mem_cgroup_under_socket_pressure(sk->sk_memcg))
+			pressured = true;
+	}
 
 	/* Under limit. */
-	if (allocated <= sk_prot_mem_limits(sk, 0)) {
+	if (allocated <= sk_prot_mem_limits(sk, 0))
 		sk_leave_memory_pressure(sk);
+	else
+		pressured = true;
+
+	/* No pressure observed in global/memcg. */
+	if (!pressured)
 		return 1;
-	}
 
 	/* Under pressure. */
 	if (allocated > sk_prot_mem_limits(sk, 1))
-- 
2.37.3