Received-SPF: pass (google.com: domain of linux-kernel+bounces-62379-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: "Luck, Tony" <tony.luck@intel.com>
To: "paulmck@kernel.org" <paulmck@kernel.org>, Borislav Petkov <bp@alien8.de>
CC: Yazen Ghannam <yazen.ghannam@amd.com>, "Naik, Avadhut" <avadnaik@amd.com>,
	"Mehta, Sohil" <sohil.mehta@intel.com>, "x86@kernel.org" <x86@kernel.org>,
	"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Avadhut Naik
	<avadhut.naik@amd.com>
Subject: RE: [PATCH 2/2] x86/MCE: Add command line option to extend MCE
 Records pool
Thread-Topic: [PATCH 2/2] x86/MCE: Add command line option to extend MCE
 Records pool
Thread-Index: AQHaWhj+DLVtkWOA50OiEqZPMnN2ZbEBPHkAgAE1PoCAAAHSAIAABzoAgAAEd4CAALjhgIAA4DsAgADqjICAAhC1AIAAAfPggAANwwCAAACQYIAABwgAgAAJWQCAAAj40A==
Date: Mon, 12 Feb 2024 21:18:51 +0000
Message-ID: <SJ1PR11MB608319A906F5DB0AB18C1913FC482@SJ1PR11MB6083.namprd11.prod.outlook.com>
References: <7a4945b0-322a-444e-a0ca-860a062a49c3@amd.com>
 <20240209205111.GGZcaQP1gb6C9m0WZB@fat_crate.local>
 <5DB0FF8D-C6DA-45DC-B287-201A9BF48BDA@alien8.de>
 <75ddf61d-8dda-47fa-9da0-24221feb22a2@amd.com>
 <20240211111455.GAZcisL09LeFPWa2EI@fat_crate.local>
 <b5904910-ed58-405f-9425-566383b48068@amd.com>
 <SJ1PR11MB6083CF3400AD2F2047D65E17FC482@SJ1PR11MB6083.namprd11.prod.outlook.com>
 <34b19db5-bd72-457c-9b6a-c2089f6be83c@amd.com>
 <SJ1PR11MB6083E7E11F6C7BCC8C6C7F21FC482@SJ1PR11MB6083.namprd11.prod.outlook.com>
 <20240212201038.GNZcp7PuIqIJndpDM9@fat_crate.local>
 <47901422-ac07-47db-bf44-3f4353e92b1d@paulmck-laptop>
In-Reply-To: <47901422-ac07-47db-bf44-3f4353e92b1d@paulmck-laptop>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?X5bK74WbQETFpRZoHyCDBMJKBBDRlfMNOOjbAqodQK+C/ylnOd92ngmFt7sU?=
 =?us-ascii?Q?LRPka5XYPqfvzyTytO6hEM1ipHjTn7hBRiAlQ/8U20VDFoYTNTR3pdjWBtMn?=
 =?us-ascii?Q?MPymNRdgB8ZH3c1UaxRFjL/tVKxn0WR9H8CO5ThAaXW5FKYbpQCfyCADK/Dk?=
 =?us-ascii?Q?kn8bhRVeegwQhwIJAY3+sY7DM18nfNwxvbMWvlTpJG5zAMfc9uPXQryU7be3?=
 =?us-ascii?Q?lP+Ud5/knj2FLpxMGYO5pZ7st1NjhLIqi9/VYX0M1mVG+G70OoXFKHVWj7dL?=
 =?us-ascii?Q?TMf3ddxT9okjWz7IcSXIa2aN4FD1qCdTJ1TshL4TUyNI0dMv3DX7wtn9UUsZ?=
 =?us-ascii?Q?Da/2OBemlz7UDgQaEUGMhfkTx7/CQjR481DIhOtMOJSNH7XV89EVdjDuLFsq?=
 =?us-ascii?Q?s1q02c7fyj7DBPMawiLNsuEolUgE7atdysLLWwVUKttAaTRuDUnkzNdaiCk1?=
 =?us-ascii?Q?PbvCGZ5HA0Q8AWg7krZkzet/mK0aU6ffISPzzi4nPWMXce1X7kJGplNcdvh3?=
 =?us-ascii?Q?86Zbr/Ms0XFaDd9vL0/pWitX9WK8VR2lIDNG5LAebxu7/trprZbkXMaUU2Yj?=
 =?us-ascii?Q?GhMRQ96peego3IcAhwyKhnROfNMXLUdI89nGem6ffy90ChcyE1LTJwQ+VbZM?=
 =?us-ascii?Q?PZAj8DKVW+6e8WV0SvWSyWLkgWxpLDvUPOKKZS7H00oYco9QX4R+OPGuJGsO?=
 =?us-ascii?Q?DTSWBXAYhE5rn4NV5rb1hzTzghLlDVZIwZTGTvOACBrL7Qqt5CRA66Saz+wF?=
 =?us-ascii?Q?Cd6jxRuId5DQ21np0ISUqY+nMAxHbxnUdQ+gnScaGJhVfkSEUpF0JFAeDo+a?=
 =?us-ascii?Q?v4enFJMSiihEnwKn9ZjCc6egwO7BeS50FFtaurTPOfy0MmPffmmS3TZtk4TB?=
 =?us-ascii?Q?Dtz5v1gZLfKTDXpTDBtEgmjQLPtzM4U0U/0R1cZywGGQ1jwg5orxIoxh41gG?=
 =?us-ascii?Q?IfUbdmIxbK1MQGqCgnKHz2pEQCHM2bxBWnXnePPmBAdbPjrYO+ZQgVqbIK78?=
 =?us-ascii?Q?xqmkdfYvaYGLv5SZ8L+GS8xIAVhdNgYgcU1ulTxoEqeBHJ8Iz9gZQ1QCV5sd?=
 =?us-ascii?Q?WNGEbnpYwYHzvMG04jfEl65GX4v/XrL+dHQDy5oKwlFmJgKpC3cYnmXCSYRq?=
 =?us-ascii?Q?mccFvZ8WY9Zbz5eDeX8/ZxkBdf3R7pEfvcJ4hPTVPCg53bLyv5KSsayFZTc5?=
 =?us-ascii?Q?/jJUApMSRc+begNS1j1Q5vaTZ1MEhNPMUVCXn+lui+ERTFiQ6R/M3TPLzJ0V?=
 =?us-ascii?Q?byhOuoHABc1mRlqSXUhYSE5W9F12RpPZvRNGFd8a5NZ/IHyNQlGg29cFFjPy?=
 =?us-ascii?Q?i8BNcRucbjDF0K3xN/swMJzfqRMicRt3F5bfvaOMRfGOXrcecXJezt/CT0HP?=
 =?us-ascii?Q?Czk0yDLItVESHFdsSTlx660Dt9L0r4mrhf/ywuaAHypSwPz16LPBppo8loTh?=
 =?us-ascii?Q?LB/jMnDkoAFBwp4i+cM9QF18hiGOlJA0b0XUeIfUECkw+2wEYviq4AudZnPo?=
 =?us-ascii?Q?P5FzBQKzjSN4J2GTaC7/Mc870Uaz+ELjF/D8qdrSAnAf+1QzUT0BbyQGGGyC?=
 =?us-ascii?Q?sUdBm8ZQDuSYSpwSDYsLk1+V/Qz5bziV/QgSkvOQ?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk
X-Mailing-List: linux-kernel@vger.kernel.org
List-Id: <linux-kernel.vger.kernel.org>
List-Subscribe: <mailto:linux-kernel+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:linux-kernel+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: SJ1PR11MB6083.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: a3beb5c2-c007-4282-9b9c-08dc2c10362a
X-MS-Exchange-CrossTenant-originalarrivaltime: 12 Feb 2024 21:18:51.9359
 (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: /0pmq4EoT/Vs9GQ1Zr+LhpWhT1mfdhTiAtFF88Sb/5q6ERgnoRaHgnulUKTWk5sWNKsMbpW7pUejfxkCT1h6Nw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CO6PR11MB5633
X-OriginatorOrg: intel.com

>> and this is exactly what we're doing - adding new memory.
>
> Is the #MC adding new memory, or is the interrupted context adding new
> memory?

The interrupted context is adding the memory.

>> So, until we're absolutely sure that it is ok to interrupt a context
>> holding a spinlock with a #MC which is non-maskable, I don't think we
>> wanna do this.
>
> If it is the #MC adding new memory, agreed.

Not what is happening.

> If the #MC is simply traversing the list, and the interrupted context
> was in the midst of adding a new element, this should be no worse than
> some other CPU traversing the list while this CPU is in the midst of
> adding a new element.
>
> Or am I missing a turn in here somewhere?

Not missing anything. I believe you've answered the question.

-Tony