The callers of mem_cgroup_under_socket_pressure() should always make
sure that (mem_cgroup_sockets_enabled && sk->sk_memcg) is true. So
instead of coding around all the callsites, put the dependencies into
mem_cgroup_under_socket_pressure() to avoid redundancy and possibly
bugs.
This change might also introduce slight function call overhead *iff*
the function gets expanded in the future. But for now this change
doesn't make binaries different (checked by vimdiff) except the one
net/ipv4/tcp_input.o (by scripts/bloat-o-meter), which is probably
negligible to performance:
add/remove: 0/0 grow/shrink: 1/2 up/down: 5/-5 (0)
Function old new delta
tcp_grow_window 573 578 +5
tcp_try_rmem_schedule 1083 1081 -2
tcp_check_space 324 321 -3
Total: Before=44647, After=44647, chg +0.00%
So folding the dependencies into mem_cgroup_under_socket_pressure()
is generally a good thing and provides better readablility.
Signed-off-by: Abel Wu <wuyun.abel@xxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 2 ++
include/net/sock.h | 3 +--
include/net/tcp.h | 3 +--
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 222d7370134c..a1aead140ff8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1743,6 +1743,8 @@ void mem_cgroup_sk_alloc(struct sock *sk);
void mem_cgroup_sk_free(struct sock *sk);
static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
{
+ if (!mem_cgroup_sockets_enabled || !memcg)
+ return false;
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_pressure)
return true;
do {
diff --git a/include/net/sock.h b/include/net/sock.h
index 8b7ed7167243..641c9373b44b 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1414,8 +1414,7 @@ static inline bool sk_under_memory_pressure(const struct sock *sk)
if (!sk->sk_prot->memory_pressure)
return false;
- if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
- mem_cgroup_under_socket_pressure(sk->sk_memcg))
+ if (mem_cgroup_under_socket_pressure(sk->sk_memcg))
return true;
return !!*sk->sk_prot->memory_pressure;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 04a31643cda3..3c5e3718b454 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -261,8 +261,7 @@ extern unsigned long tcp_memory_pressure;
/* optimized version of sk_under_memory_pressure() for TCP sockets */
static inline bool tcp_under_memory_pressure(const struct sock *sk)
{
- if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
- mem_cgroup_under_socket_pressure(sk->sk_memcg))
+ if (mem_cgroup_under_socket_pressure(sk->sk_memcg))
return true;
return READ_ONCE(tcp_memory_pressure);
--
2.37.3
