UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

net: avoid possible false sharing in sk_leave_memory_pressure() 

As mentioned in https://github.com/google/ktsan/wiki/READ_ONCE-and-WRITE_ONCE#it-may-improve-performance
a C compiler can legally transform :

if (memory_pressure && *memory_pressure)
        *memory_pressure = 0;

to :

if (memory_pressure)
        *memory_pressure = 0;

Fixes: 0604475119 ("tcp: add TCPMemoryPressuresChrono counter")
Fixes: 180d8cd942 ("foundations of per-cgroup memory pressure controlling.")
Fixes: 3ab224be6d ("[NET] CORE: Introducing new memory accounting interface.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
This commit is contained in:
Eric Dumazet 2019-10-09 12:55:53 -07:00 committed by Jakub Kicinski
parent 4ffdd22e49
commit 503978aca4
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
net/core/sock.c
View File

@ -2334,8 +2334,8 @@ static void sk_leave_memory_pressure(struct sock *sk)
} else {
unsigned long *memory_pressure = sk->sk_prot->memory_pressure;
if (memory_pressure && *memory_pressure)
*memory_pressure = 0;
if (memory_pressure && READ_ONCE(*memory_pressure))
WRITE_ONCE(*memory_pressure, 0);
}
}