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[209.132.180.67]) by mx.google.com with ESMTP id w188si101625oig.183.2020.03.25.11.06.33; Wed, 25 Mar 2020 11:06:47 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=aculab.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727855AbgCYSFb convert rfc822-to-8bit (ORCPT + 99 others); Wed, 25 Mar 2020 14:05:31 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([146.101.78.151]:37399 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726820AbgCYSFb (ORCPT ); Wed, 25 Mar 2020 14:05:31 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-119-4aYfkUtjPiqI5hRXUU8wVw-1; Wed, 25 Mar 2020 18:05:28 +0000 X-MC-Unique: 4aYfkUtjPiqI5hRXUU8wVw-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Wed, 25 Mar 2020 18:05:27 +0000 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Wed, 25 Mar 2020 18:05:27 +0000 From: David Laight To: 'Marcelo Tosatti' , Thomas Gleixner CC: Chris Friesen , "linux-kernel@vger.kernel.org" , "Christoph Lameter" , Jim Somerville , Andrew Morton , Frederic Weisbecker , Peter Zijlstra Subject: RE: [PATCH v2] isolcpus: affine kernel threads to specified cpumask Thread-Topic: [PATCH v2] isolcpus: affine kernel threads to specified cpumask Thread-Index: AQHWAe/VaQ9sFT2YFEq1MC0lycC6lqhZmykw Date: Wed, 25 Mar 2020 18:05:27 +0000 Message-ID: References: <20200323135414.GA28634@fuller.cnet> <87k13boxcn.fsf@nanos.tec.linutronix.de> <87imiuq0cg.fsf@nanos.tec.linutronix.de> <20200324152016.GA25422@fuller.cnet> In-Reply-To: <20200324152016.GA25422@fuller.cnet> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marcelo Tosatti > Sent: 24 March 2020 15:20 > > This is a kernel enhancement to configure the cpu affinity of kernel > threads via kernel boot option isolcpus=no_kthreads,, > > When this option is specified, the cpumask is immediately applied upon > thread launch. This does not affect kernel threads that specify cpu > and node. > > This allows CPU isolation (that is not allowing certain threads > to execute on certain CPUs) without using the isolcpus=domain parameter, > making it possible to enable load balancing on such CPUs > during runtime ... How about making it possible to change the default affinity for new kthreads at run time? Is it possible to change the affinity of existing threads? Or maybe only those that didn't specify an explicit one?? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)