From patchwork Fri Aug 9 14:58:11 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 11086621 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7B6951398 for ; Fri, 9 Aug 2019 14:59:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6A6D21FFD8 for ; Fri, 9 Aug 2019 14:59:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5E2311FFDB; Fri, 9 Aug 2019 14:59:56 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E756C1FF73 for ; Fri, 9 Aug 2019 14:59:55 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hw6MD-0006zU-K1; Fri, 09 Aug 2019 14:59:05 +0000 Received: from us1-rack-dfw2.inumbo.com ([104.130.134.6]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1hw6M1-0006b6-Ve for xen-devel@lists.xenproject.org; Fri, 09 Aug 2019 14:58:54 +0000 X-Inumbo-ID: 30c52eff-bab6-11e9-8980-bc764e045a96 Received: from mx1.suse.de (unknown [195.135.220.15]) by us1-rack-dfw2.inumbo.com (Halon) with ESMTPS id 30c52eff-bab6-11e9-8980-bc764e045a96; Fri, 09 Aug 2019 14:58:48 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0BA97B0E5; Fri, 9 Aug 2019 14:58:47 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org Date: Fri, 9 Aug 2019 16:58:11 +0200 Message-Id: <20190809145833.1020-27-jgross@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190809145833.1020-1-jgross@suse.com> References: <20190809145833.1020-1-jgross@suse.com> Subject: [Xen-devel] [PATCH v2 26/48] xen/sched: rework and rename vcpu_force_reschedule() X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Stefano Stabellini , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Julien Grall , Jan Beulich , Dario Faggioli , =?utf-8?q?Roger_Pau_Monn=C3=A9?= MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP vcpu_force_reschedule() is only used for modifying the periodic timer of a vcpu. Forcing a vcpu to give up the physical cpu for that purpose is kind of brutal. So instead of doing the reschedule dance just operate on the timer directly. In case we are modifying the timer of the currently running vcpu we can just do that. In case it is for a foreign vcpu we should pause it for that purpose like we do for all other vcpu state modifications. Rename the function to vcpu_set_periodic_timer() as this now reflects the functionality. Signed-off-by: Juergen Gross --- V1: latch NOW() only after stopping the timer (Jan Beulich) --- xen/arch/x86/pv/shim.c | 4 +--- xen/common/domain.c | 6 ++---- xen/common/schedule.c | 24 ++++++++++++++---------- xen/include/xen/sched.h | 2 +- 4 files changed, 18 insertions(+), 18 deletions(-) diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c index 324ca27f93..5edbcd9ac5 100644 --- a/xen/arch/x86/pv/shim.c +++ b/xen/arch/x86/pv/shim.c @@ -410,7 +410,7 @@ int pv_shim_shutdown(uint8_t reason) unmap_vcpu_info(v); /* Reset the periodic timer to the default value. */ - v->periodic_period = MILLISECS(10); + vcpu_set_periodic_timer(v, MILLISECS(10)); /* Stop the singleshot timer. */ stop_timer(&v->singleshot_timer); @@ -419,8 +419,6 @@ int pv_shim_shutdown(uint8_t reason) if ( v != current ) vcpu_unpause_by_systemcontroller(v); - else - vcpu_force_reschedule(v); } return 0; diff --git a/xen/common/domain.c b/xen/common/domain.c index 91b01c220e..863b7cae35 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -1479,15 +1479,13 @@ long do_vcpu_op(int cmd, unsigned int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg) if ( set.period_ns > STIME_DELTA_MAX ) return -EINVAL; - v->periodic_period = set.period_ns; - vcpu_force_reschedule(v); + vcpu_set_periodic_timer(v, set.period_ns); break; } case VCPUOP_stop_periodic_timer: - v->periodic_period = 0; - vcpu_force_reschedule(v); + vcpu_set_periodic_timer(v, 0); break; case VCPUOP_set_singleshot_timer: diff --git a/xen/common/schedule.c b/xen/common/schedule.c index 3f8fffc329..4c488ddde0 100644 --- a/xen/common/schedule.c +++ b/xen/common/schedule.c @@ -877,21 +877,25 @@ static void vcpu_migrate_finish(struct vcpu *v) } /* - * Force a VCPU through a deschedule/reschedule path. - * For example, using this when setting the periodic timer period means that - * most periodic-timer state need only be touched from within the scheduler - * which can thus be done without need for synchronisation. + * Set the periodic timer of a vcpu. */ -void vcpu_force_reschedule(struct vcpu *v) +void vcpu_set_periodic_timer(struct vcpu *v, s_time_t value) { - spinlock_t *lock = unit_schedule_lock_irq(v->sched_unit); + s_time_t now; - if ( v->sched_unit->is_running ) - vcpu_migrate_start(v); + if ( v != current ) + vcpu_pause(v); + else + stop_timer(&v->periodic_timer); - unit_schedule_unlock_irq(lock, v->sched_unit); + now = NOW(); + v->periodic_period = value; + v->periodic_last_event = now; - vcpu_migrate_finish(v); + if ( v != current ) + vcpu_unpause(v); + else if ( value != 0 ) + set_timer(&v->periodic_timer, now + value); } static bool sched_check_affinity_broken(struct sched_unit *unit) diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index 0cece3b921..7f84b823cb 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -896,7 +896,7 @@ struct scheduler *scheduler_get_default(void); struct scheduler *scheduler_alloc(unsigned int sched_id, int *perr); void scheduler_free(struct scheduler *sched); int schedule_cpu_switch(unsigned int cpu, struct cpupool *c); -void vcpu_force_reschedule(struct vcpu *v); +void vcpu_set_periodic_timer(struct vcpu *v, s_time_t value); int cpu_disable_scheduler(unsigned int cpu); /* We need it in dom0_setup_vcpu */ void sched_set_affinity(struct vcpu *v, const cpumask_t *hard,