Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 22 May 2023 14:54:55 +0200
From:   Simon Horman <simon.horman@corigine.com>
To:     Abel Wu <wuyun.abel@bytedance.com>
Cc:     "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Glauber Costa <glommer@parallels.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/4] sock: Remove redundant cond of memcg pressure
Message-ID: <ZGtmH/0ytVZkkmCP@corigine.com>
References: <20230522070122.6727-1-wuyun.abel@bytedance.com>
 <20230522070122.6727-5-wuyun.abel@bytedance.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230522070122.6727-5-wuyun.abel@bytedance.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?NxeTx1k0M7k8eah0dVNzdWoAod46osZN4VbhonBHVjv4ZiCUyibi2dbwRVV7?=
 =?us-ascii?Q?7ZiVN4LgtxgdhsEOrXs4ONBR1LppIyLW317yzOzKB+ItK7RmdLAkZGLNTz1a?=
 =?us-ascii?Q?DNkv2PmiBy067qjeN9x1CB+uD7HVYzzyCy/j6CS0THzBn01tT+vH5OoOPTgL?=
 =?us-ascii?Q?Wyd4FTs9n+iaMKM81COx450Abpeir9l2CVx7Xon/JJDvOm/IiYcJjGECvzKf?=
 =?us-ascii?Q?wj2UQOtqHXp7CKJ4AwVII7aD8x1W4UhQIwyTDA+w5nMvA0/ZVLb6DpbiLzgb?=
 =?us-ascii?Q?xQSDr9ddnieyBEkqLXro49LrsXRXVHFzFmwdMWEC1/zGZKrL9SU77ixa3Xuo?=
 =?us-ascii?Q?DF7IQ3bj/PGQ3F37KFir0ZgaxDjVXoWAWgOv1Vsm1JSJRpZVFNNdHLNTp3AG?=
 =?us-ascii?Q?/0nXWX2s9KZHypDoTNT26hio+kaWae1ZBx+AfwxfvTnSBpGRQNf1MF2rJgGb?=
 =?us-ascii?Q?gTXolPDuG+peC2DSb3MKHDxp2FA8h6opTpzrpoqYiS1IWmx3AbFI+Gy+hvJK?=
 =?us-ascii?Q?97QdQt/bhPNBzrsfoWbBjYbWPhe/ZOUaxNfcq3iMH8bZ6wzhl1DOx3wOYHSj?=
 =?us-ascii?Q?C5yZakcbrzHmsY3jhibbLBQMJ3Not0v+snWPinEpSHK+F9F5Ka/Xuk7aa9zh?=
 =?us-ascii?Q?825uKFJIjRQbn4I42fK0dl3akRIAVM4OcvymGSfrNU3PxVdtoFGHdthxVNu7?=
 =?us-ascii?Q?gLt1thKUrcgbjw+rWZ4z+GYv/GL5JWxxSoM3QVq6r2IJXjsMRkIAaR4ywhGi?=
 =?us-ascii?Q?4l1TBChBpXkbtsrOAXlgY/4ZWvChcp1vgJ2jXhPWhjgjqIt4omu7aoA2/OhR?=
 =?us-ascii?Q?sacNStYgWtIp3SqfB/n+QuFqnoW7SlKlDBCPQXVaU2A9OB3WRgrEReMIwZK6?=
 =?us-ascii?Q?RLwGKqFy4MsMIsDYoZQreKyJ631oVJ2TJ1KHOjFSQCr2eMvlgwHF3qfCWh5D?=
 =?us-ascii?Q?mVUcUUO+/ikrkfvZy7wg1GL+ymmqKx9zJhoU0d0DlDIbWK2DRFenB0TWXcdx?=
 =?us-ascii?Q?IFWWNlau9RnxmIAqz7cYsfLOpIc14TWO55DxcXIAJY99O/799EMcDFblzM/B?=
 =?us-ascii?Q?uYGROOugvCfmIY4m6M4p69gcmT/27ubkepLfUx4Mjk+9hrQl/nPV3acR6DlS?=
 =?us-ascii?Q?8GFeLl5jZp9+cQ06vNWyAhDjh5osDO8kYv2/LYC0yuc1kIaheK0DBSfZns1C?=
 =?us-ascii?Q?UjBDiWQcfaBYWB56qgyoj/I5vLKZGi0G05r7yXXdTavw5ueUE86h7hd0DZ5u?=
 =?us-ascii?Q?YU300grRFLu44Yj9zLA0pD9MJXn2qUgnGCIe+f+VW15YCU+qx29iw66EShQx?=
 =?us-ascii?Q?rKY9IiNBb4tbUL7mfxoALllz9yXHyRZ8u/IcmBp+phu8AQMz0Rrve5+GdfWf?=
 =?us-ascii?Q?clmWTWo8gPFWesvWIndN+M03UcN3XNvWwOdI5cip22CAOBUZixye9F5UQJFN?=
 =?us-ascii?Q?GPxBEIRcOZCQsGedgJDhQ3DtKNmc6tBgpvO3qG8G9EuhRHDsgIK9vHNTogmU?=
 =?us-ascii?Q?vYCZxn0MeX9jOC61SptmGxVAUYPv9Kv5c/wE/WsRwnnWNyK5i0Fs8HVbgJNq?=
 =?us-ascii?Q?frTIhzMZ8zEZuGpZVCopGATG+86nQ4WMFm3/59N2Nwe64DGkVhvDGTzwdu+w?=
 =?us-ascii?Q?CMQ5saz4oyB+9G7vNnpYMNDkiu2E85fNeB0cnd0e168FvCP4QlH78Hv6T1d1?=
 =?us-ascii?Q?2q3LbQ=3D=3D?=
X-OriginatorOrg: corigine.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 02e29651-c14c-47b7-f2ef-08db5ac3c162
X-MS-Exchange-CrossTenant-AuthSource: PH0PR13MB4842.namprd13.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 May 2023 12:55:01.4074
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: fe128f2c-073b-4c20-818e-7246a585940c
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: ecQlltXcBHUKXaE+qGqO2XLlz2UQe4KX5azisMiv9rWqfdetAJYrGTCY76OGsYTGHs1Ysj7bhz6H14NiqNoD7TbOK0EggJ0DOZEZBNX92jQ=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR13MB5468
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,
        T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, May 22, 2023 at 03:01:22PM +0800, Abel Wu wrote:
> Now with the preivous patch, __sk_mem_raise_allocated() considers

nit: s/preivous/previous/

> the memory pressure of both global and the socket's memcg on a func-
> wide level, making the condition of memcg's pressure in question
> redundant.
> 
> Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
> ---
>  net/core/sock.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 7641d64293af..baccbb58a11a 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -3029,9 +3029,14 @@ int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
>  	if (sk_has_memory_pressure(sk)) {
>  		u64 alloc;
>  
> -		if (!sk_under_memory_pressure(sk))
> +		if (!sk_under_global_memory_pressure(sk))
>  			return 1;
>  		alloc = sk_sockets_allocated_read_positive(sk);
> +		/*
> +		 * If under global pressure, allow the sockets that are below
> +		 * average memory usage to raise, trying to be fair among all
> +		 * the sockets under global constrains.
> +		 */

nit:
		/* Multi-line comments in networking code
		 * look like this.
		 */

>  		if (sk_prot_mem_limits(sk, 2) > alloc *
>  		    sk_mem_pages(sk->sk_wmem_queued +
>  				 atomic_read(&sk->sk_rmem_alloc) +
> -- 
> 2.37.3
> 
>