From patchwork Mon Feb 9 16:04:43 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rik van Riel X-Patchwork-Id: 5802021 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C0327BF440 for ; Mon, 9 Feb 2015 16:08:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E7E322010B for ; Mon, 9 Feb 2015 16:07:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 125AB20107 for ; Mon, 9 Feb 2015 16:07:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933502AbbBIQHY (ORCPT ); Mon, 9 Feb 2015 11:07:24 -0500 Received: from shelob.surriel.com ([74.92.59.67]:47999 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933521AbbBIQE6 (ORCPT ); Mon, 9 Feb 2015 11:04:58 -0500 Received: from [2002:4a5c:3b41:1:224:e8ff:fe38:995c] (helo=annuminas.surriel.com) by shelob.surriel.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1YKqpT-0002KZ-7D; Mon, 09 Feb 2015 11:04:55 -0500 Received: from annuminas.surriel.com (localhost.localdomain [127.0.0.1]) by annuminas.surriel.com (8.14.8/8.14.5) with ESMTP id t19G4tCk022420; Mon, 9 Feb 2015 11:04:55 -0500 Received: (from riel@localhost) by annuminas.surriel.com (8.14.8/8.14.8/Submit) id t19G4tBf022419; Mon, 9 Feb 2015 11:04:55 -0500 X-Authentication-Warning: annuminas.surriel.com: riel set sender to riel@redhat.com using -f From: riel@redhat.com To: paulmck@linux.vnet.ibm.com Cc: linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will.deacon@arm.com, fweisbec@gmail.com, kvm@vger.kernel.org, mtosatti@redhat.com, borntraeger@de.ibm.com, mingo@kernel.org, oleg@redhat.com, lcapitulino@redhat.com, pbonzini@redhat.com, Rik van Riel Subject: [PATCH 5/6] kvm, rcu, nohz: use RCU extended quiescent state when running KVM guest Date: Mon, 9 Feb 2015 11:04:43 -0500 Message-Id: <1423497884-21615-6-git-send-email-riel@redhat.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1423497884-21615-1-git-send-email-riel@redhat.com> References: <1423497884-21615-1-git-send-email-riel@redhat.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rik van Riel The host kernel is not doing anything while the CPU is executing a KVM guest VCPU, so it can be marked as being in an extended quiescent state, identical to that used when running user space code. The only exception to that rule is when the host handles an interrupt, which is already handled by the irq code, which calls rcu_irq_enter and rcu_irq_exit. The guest_enter and guest_exit functions already switch vtime accounting independent of context tracking, so leave those calls where they are, instead of moving them into the context tracking code. Signed-off-by: Rik van Riel --- include/linux/context_tracking.h | 8 +++++++- include/linux/context_tracking_state.h | 1 + include/linux/kvm_host.h | 3 ++- 3 files changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 29d7fecb365a..c70d7e760061 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -43,7 +43,7 @@ static inline enum ctx_state exception_enter(void) static inline void exception_exit(enum ctx_state prev_ctx) { if (context_tracking_is_enabled()) { - if (prev_ctx == IN_USER) + if (prev_ctx != IN_KERNEL) context_tracking_enter(prev_ctx); } } @@ -74,6 +74,9 @@ static inline void context_tracking_init(void) { } #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN static inline void guest_enter(void) { + if (context_tracking_is_enabled()) + context_tracking_enter(IN_GUEST); + if (vtime_accounting_enabled()) vtime_guest_enter(current); else @@ -86,6 +89,9 @@ static inline void guest_exit(void) vtime_guest_exit(current); else current->flags &= ~PF_VCPU; + + if (context_tracking_is_enabled()) + context_tracking_exit(IN_GUEST); } #else diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index 97a81225d037..f3ef027af749 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -15,6 +15,7 @@ struct context_tracking { enum ctx_state { IN_KERNEL = 0, IN_USER, + IN_GUEST, } state; }; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 26f106022c88..c7828a6a9614 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -772,7 +772,8 @@ static inline void kvm_guest_enter(void) * one time slice). Lets treat guest mode as quiescent state, just like * we do with user-mode execution. */ - rcu_virt_note_context_switch(smp_processor_id()); + if (!context_tracking_cpu_is_enabled()) + rcu_virt_note_context_switch(smp_processor_id()); } static inline void kvm_guest_exit(void)