From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 139E2C433DF for ; Tue, 21 Jul 2020 16:23:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD58120771 for ; Tue, 21 Jul 2020 16:23:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730205AbgGUQXG convert rfc822-to-8bit (ORCPT ); Tue, 21 Jul 2020 12:23:06 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:44657 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728268AbgGUQXG (ORCPT ); Tue, 21 Jul 2020 12:23:06 -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-61-AirEoyffNvC1547t3qSSww-1; Tue, 21 Jul 2020 17:23:02 +0100 X-MC-Unique: AirEoyffNvC1547t3qSSww-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; Tue, 21 Jul 2020 17:23:01 +0100 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; Tue, 21 Jul 2020 17:23:01 +0100 From: David Laight To: 'Thomas Gleixner' , Frederic Weisbecker CC: LKML , "x86@kernel.org" , Oleg Nesterov , "Eric W. Biederman" , John Stultz , Paolo Bonzini Subject: RE: [patch V2 2/5] posix-cpu-timers: Convert the flags to a bitmap Thread-Topic: [patch V2 2/5] posix-cpu-timers: Convert the flags to a bitmap Thread-Index: AQHWX3mJuHICg1ghhkWtnXn9ULrVJqkSNyjg Date: Tue, 21 Jul 2020 16:23:01 +0000 Message-ID: References: <20200716201923.228696399@linutronix.de> <20200716202044.625081169@linutronix.de> <20200721123452.GA9290@lenoir> <874kq04zn3.fsf@nanos.tec.linutronix.de> In-Reply-To: <874kq04zn3.fsf@nanos.tec.linutronix.de> 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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com 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: Thomas Gleixner > Sent: 21 July 2020 17:11 > > Frederic Weisbecker writes: > > On Thu, Jul 16, 2020 at 10:19:25PM +0200, Thomas Gleixner wrote: > >> --- a/kernel/time/posix-cpu-timers.c > >> +++ b/kernel/time/posix-cpu-timers.c > >> @@ -25,7 +25,7 @@ void posix_cputimers_group_init(struct p > >> posix_cputimers_init(pct); > >> if (cpu_limit != RLIM_INFINITY) { > >> pct->bases[CPUCLOCK_PROF].nextevt = cpu_limit * NSEC_PER_SEC; > >> - pct->timers_active = true; > >> + set_bit(CPUTIMERS_ACTIVE, &pct->flags); > > > > I guess this one could be __set_bit(). > > True :) Hmmm... does this code need the bit operations to be atmomic? If not then an bitmap is completely the wrong thing to be using. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)