Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8;
Message-ID: <b7e0e0f6-90e6-4fcf-9fe5-957d6a0864ca@intel.com>
Date:   Mon, 27 Nov 2023 15:12:29 +0100
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH net-next v5 01/14] page_pool: make sure frag API fields
 don't span between cachelines
Content-Language: en-US
To:     Jakub Kicinski <kuba@kernel.org>
CC:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Michal Kubiak <michal.kubiak@intel.com>,
        Larysa Zaremba <larysa.zaremba@intel.com>,
        Alexander Duyck <alexanderduyck@fb.com>,
        Yunsheng Lin <linyunsheng@huawei.com>,
        "David Christensen" <drc@linux.vnet.ibm.com>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        "Paul Menzel" <pmenzel@molgen.mpg.de>, <netdev@vger.kernel.org>,
        <intel-wired-lan@lists.osuosl.org>, <linux-kernel@vger.kernel.org>
References: <20231124154732.1623518-1-aleksander.lobakin@intel.com>
 <20231124154732.1623518-2-aleksander.lobakin@intel.com>
 <20231126145457.400726e4@kernel.org>
From:   Alexander Lobakin <aleksander.lobakin@intel.com>
In-Reply-To: <20231126145457.400726e4@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?T0pqbVJuNzRSQm5KdThaSDNzQ1p2akVUZzhQY00rQ2J4Q2NZcUVVRXJ5OGs3?=
 =?utf-8?B?MUtNKzVDZnNGQlMrVFFzd2Nndk93V3BpTTJGSTFtVHRiMUlsQ2x5SEZMamNv?=
 =?utf-8?B?bjhJNG8zY3pvYllqR011Mm9TRDBZU0N0QlJ1M2hoRUdLVlFiUXk0WVJDdGU0?=
 =?utf-8?B?RlY5MjdsTTFIYWRyRCtZeXVLS0VVU0NpdlY0RW5wYjdEVHBqYkpEYnFKTlpY?=
 =?utf-8?B?cTAweGkxbC9HTWVtbmVyWHRsRnBBN2R3RjE0MTQ5cURWNHRFK0VyRHVkSUtx?=
 =?utf-8?B?TjFuY3JaVXN5SncrUVZwNTVaYmhDT2xOQUZPYjdEWHNIV1RJaDZjUmdBN2w2?=
 =?utf-8?B?QXlqT0dmcTJkWFNXZ2MxZGIzQjhISldZTzBXVlRzWHNrY2dlalJCWUJWOGFo?=
 =?utf-8?B?eEVSODlpVXVvM3V6QjRQREw1eWJSSGdxWm15WW9EREJzVHF0V1l2V3Yzc0Z5?=
 =?utf-8?B?UUJsUURVYU1NeEtNSlljeUVYdjFpaGQvY1pHeVpqbnNVS0J2bFkrcmtXZ2hI?=
 =?utf-8?B?Rzk3SWhUWEUzYmhXcmQrRkJaL0RRL3JOQ00xVmNtYi9IbzIyUVd2RnJTd3Y0?=
 =?utf-8?B?ZlBoaWF1MmRQaXdpOXpWZlUvbG1wM2FyRUJWbkNFcHdRY3lOZzN4ZmJneHZq?=
 =?utf-8?B?R0JiQXo0NUJmeEJOcERTeTZuaTN2ZFR6Q2IyMGRTb3h4SHZDVkpRQmRVSllk?=
 =?utf-8?B?STBSTjZOaTZhdkN2SmtjcEVBamU4Rk9mWnFhRyt1Z0ZHNFpzU2duVlE3VWhY?=
 =?utf-8?B?Q01hS3pHNU9kdUxXNUM1akFkd0x5bWJtZHdCTXYyMXpORG52RG9nbk96SW1q?=
 =?utf-8?B?eEVCemFmSE9Jd3VCOEk5c2xnMlg5aTZ0L0Y1Vm50MGdld2tQcnJkdGE0c2hR?=
 =?utf-8?B?OUQ1VERtdXQxUkFBNVZmSDdDSUtDTkxXVWM2Zm5HMnBEbXJrdkZyK29PWjU4?=
 =?utf-8?B?YjhuS1p1MFdQQkp6UkJXdkJjUUhpcnIvNTU1T3R1cWdqUGE0UGp6UWh4N3k5?=
 =?utf-8?B?OVc3bDUxMEwzTWhIU0trQ2lreXNBNHRzYXpoM2I4ZEVmS1F1cFRPYWlISXA4?=
 =?utf-8?B?bXIyS2k0c25RbHFVNEcvYTlwTUZreWtEWUduNXBEbm1MMzA4T2ZQeXJKMmhm?=
 =?utf-8?B?b0s2cUdvMmxJeVJla0tic0t1K2lDVXNMbFJPK0N2ME5ZSDZYRTRDeFNlY3pV?=
 =?utf-8?B?WjVCQUlKQTgxeEtlTk5vSkhkMGtqelpuMFd3MklKcFZvbFAzVXNnVE53MFdT?=
 =?utf-8?B?SHk5TDFOYUtsNUJhZFZzWUU0bERNcmpaVGxwWDA5UzJYNnhkSjFzcHlOMURq?=
 =?utf-8?B?MkMwb0JaaDNMbjNoZEVtaG9oY3R4RlVoMUNnZlVlcm1MWC90cThXMDNoNFBT?=
 =?utf-8?B?UFMwNlpGdU5xQUhvcmFXQy9ZcUQ2bzhQbnVreWUzK0pySUZVekcrOGRMUWhX?=
 =?utf-8?B?NHcyb3VkdnVCUTdLRVBRNWJnaHd2UWs5RlVBNjhjazFqWEdJb2VlMThtZjhO?=
 =?utf-8?B?TUZSNi9uVGNyVEs2clFWODdvWlpnUGpOdkN6UmdxNDFnd1ZTK3FsUWNGa2Z5?=
 =?utf-8?B?Y2F5cmhVTVhiL28zMEtSeXN0V3pOSzk0QkRNQUxUM0dhSEJjcndmVmREZm13?=
 =?utf-8?B?UlBPMDM5TW1wWloyeHZJclFnNWlSVUN2V1BtTi94Z2s3Ym1heDBLcHZxcnI4?=
 =?utf-8?B?L3VNQWRsemxnMlNPclIxQ3hHdFpDRXBUbHAzVE1vZTNwTTZuYU9tb3pTSlJ4?=
 =?utf-8?B?bmlWdzBZdXY2YnZCL25Nc2Z5c3Eya0wwR1ZwVHZQN0xON0YzRmZkZTU0TWtZ?=
 =?utf-8?B?Y1ZTbW5YeEZFTklGZmdwQ2pZYnFqUkJ3ajZHMHJQNUp4WXdMSEdQdElHYjFO?=
 =?utf-8?B?NHEzTUhQeTJGMnBGdHJXNi8zUzdiNitQV0ZKVnlPTkhlTCsxU09EeC9aWnhs?=
 =?utf-8?B?ZzJveElJTGVrSlovdUFkSWY4TDJjeUJGS2Roelk1LzdDRXdzUkNXTi96ayt2?=
 =?utf-8?B?V3hzSFFhMnFLcTRLamZXMktIWlBSMTNJY2hVSzVoWEVwcDJvN2R3RmoxUkVJ?=
 =?utf-8?B?N3NNWUhFV2lkcXFleHZWeGdhL1dqZjBRSGo2Vm1Ub1BZeWVwVE52REt2eS9s?=
 =?utf-8?B?Qm42RUxEWG4xc1VZeE42SmhRQlJlbldGSXFMS2FJcHpYM0JzZ2NzY29SNTFR?=
 =?utf-8?B?R1E9PQ==?=
X-MS-Exchange-CrossTenant-Network-Message-Id: ea3358fb-59cc-42d3-d8d3-08dbef52f3be
X-MS-Exchange-CrossTenant-AuthSource: DM6PR11MB3625.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Nov 2023 14:12:56.1414
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: wzi6joK9sQqyQMvIAui1g6++kA+Dkyf3GZLdpIFV8Dev+X7RhbhABhTTgMuqmZuH0XhFyZukPnkZx+qNWPpU0pvbypcH3xWlui9cX7oKu74=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR11MB8543
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE
	autolearn=unavailable autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.vger.email
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (fry.vger.email [0.0.0.0]); Mon, 27 Nov 2023 06:18:31 -0800 (PST)

From: Jakub Kicinski <kuba@kernel.org>
Date: Sun, 26 Nov 2023 14:54:57 -0800

> On Fri, 24 Nov 2023 16:47:19 +0100 Alexander Lobakin wrote:
>> -	long frag_users;
>> +	long frag_users __aligned(4 * sizeof(long));
> 
> A comment for the somewhat unusual alignment size would be good.

Roger that. Will paste a couple words from the commit message.

FYI, I had an idea of doing something like

__aligned(roundup_pow_of_2(2 * sizeof(long) + 2 * sizeof(int)))

but that looks horrible, so I stopped on the current :D There are no
functional changes between them either way.

Thanks,
Olek