diff mbox series

[net,1/3] net: generic enter_memory_pressure implementation.

Message ID 1dc63f795a2dc9fc6dd55d55f6349069ba8497cf.1579281705.git.pabeni@redhat.com
State Changes Requested
Delegated to: David Miller
Headers show
Series udp: behave under memory pressure | expand

Commit Message

Paolo Abeni Jan. 17, 2020, 5:27 p.m. UTC 
Currently sk_leave_memory_pressure() offers a generic implementation
for protocol lacking the leave_memory_pressure() helper, but
supporting the memory pressure model.

sk_enter_memory_pressure() lacks such bits. As a result we get code
duplication and additional, avoidable indirect calls.

This change provides a generic implementation for entering memory pressure,
similar to the existing sk_leave_memory_pressure().

Note: no existing protocol is affected, until the existing
enter_memory_pressure helper is removed from the relevant 'proto'
struct.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/core/sock.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/core/sock.c b/net/core/sock.c
index 8459ad579f73..8cf24dca9bde 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2323,10 +2323,14 @@  EXPORT_SYMBOL(sock_cmsg_send);
 
 static void sk_enter_memory_pressure(struct sock *sk)
 {
-	if (!sk->sk_prot->enter_memory_pressure)
-		return;
+	if (sk->sk_prot->enter_memory_pressure) {
+		sk->sk_prot->enter_memory_pressure(sk);
+	} else {
+		unsigned long *memory_pressure = sk->sk_prot->memory_pressure;
 
-	sk->sk_prot->enter_memory_pressure(sk);
+		if (memory_pressure && !READ_ONCE(*memory_pressure))
+			WRITE_ONCE(*memory_pressure, 1);
+	}
 }
 
 static void sk_leave_memory_pressure(struct sock *sk)