[Devel] [PATCH RHEL7 COMMIT] net: fix silly mistake with TCP cgroup memory pressure check

[Konstantin Khorenko]

Please consider to create a ReadyKernel patch for it.

https://readykernel.com/

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 05/26/2017 04:59 PM, Konstantin Khorenko wrote:
> The commit is pushed to "branch-rh7-3.10.0-514.16.1.vz7.32.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
> after rh7-3.10.0-514.16.1.vz7.32.4
> ------>
> commit 4ce6f75421155583e24d9d763de8f48c2d3fec16
> Author: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
> Date:   Fri May 26 17:59:47 2017 +0400
>
>     net: fix silly mistake with TCP cgroup memory pressure check
>
>     Memory pressure is referenced as a pointer in socket structure.
>     Simple check for pointer address will always return true for each socket,
>     allocated with enabled mem_cg.
>     Memory pressure value has to checked instead.
>
>     https://jira.sw.ru/browse/PSBM-66468
>
>     Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
>     Acked-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
> ---
>  include/net/tcp.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index d64d30b..f2b4843 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -298,7 +298,7 @@ extern int tcp_memory_pressure;
>  static inline bool tcp_under_memory_pressure(const struct sock *sk)
>  {
>  	if (mem_cgroup_sockets_enabled && sk->sk_cgrp)
> -		return !!sk->sk_cgrp->memory_pressure;
> +		return *sk->sk_cgrp->memory_pressure;
>
>  	return tcp_memory_pressure;
>  }
> .
>