From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754315AbcFGIea (ORCPT ); Tue, 7 Jun 2016 04:34:30 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:33713 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754189AbcFGIeA (ORCPT ); Tue, 7 Jun 2016 04:34:00 -0400 From: Wanpeng Li X-Google-Original-From: Wanpeng Li To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Wanpeng Li , Ingo Molnar , "Peter Zijlstra (Intel)" , Rik van Riel , Thomas Gleixner , Frederic Weisbecker , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Subject: [PATCH v4 3/3] sched/cputime: Add steal time support to full dynticks CPU time accounting Date: Tue, 7 Jun 2016 16:33:09 +0800 Message-Id: <1465288389-3542-3-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1465288389-3542-1-git-send-email-wanpeng.li@hotmail.com> References: <1465288389-3542-1-git-send-email-wanpeng.li@hotmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wanpeng Li This patch adds guest steal-time support to full dynticks CPU time accounting. After the following commit: ff9a9b4c4334 ("sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity") ... time sampling became jiffy based, even if it's still listened to ring boundaries, so steal_account_process_tick() is reused to account how many 'ticks' are stolen-time, after the last accumulation. Suggested-and-Reviewed-by: Rik van Riel Cc: Ingo Molnar Cc: Peter Zijlstra (Intel) Cc: Rik van Riel Cc: Thomas Gleixner Cc: Frederic Weisbecker Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li --- v3 -> v4: * fix grammar errors, thanks Ingo * cleanup fragile codes, thanks Ingo v2 -> v3: * convert steal time jiffies to cputime v1 -> v2: * fix divide zero bug, thanks Rik kernel/sched/cputime.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 75f98c5..9ff036b 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -257,7 +257,7 @@ void account_idle_time(cputime_t cputime) cpustat[CPUTIME_IDLE] += (__force u64) cputime; } -static __always_inline bool steal_account_process_tick(void) +static __always_inline unsigned long steal_account_process_tick(void) { #ifdef CONFIG_PARAVIRT if (static_key_false(¶virt_steal_enabled)) { @@ -279,7 +279,7 @@ static __always_inline bool steal_account_process_tick(void) return steal_jiffies; } #endif - return false; + return 0; } /* @@ -691,9 +691,13 @@ static cputime_t get_vtime_delta(struct task_struct *tsk) static void __vtime_account_system(struct task_struct *tsk) { - cputime_t delta_cpu = get_vtime_delta(tsk); + cputime_t delta_time = get_vtime_delta(tsk); + cputime_t steal_time = jiffies_to_cputime(steal_account_process_tick()); - account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu)); + if (steal_time < delta_time) { + delta_time -= steal_time; + account_system_time(tsk, irq_count(), delta_time, cputime_to_scaled(delta_time)); + } } void vtime_account_system(struct task_struct *tsk) @@ -718,13 +722,18 @@ void vtime_gen_account_irq_exit(struct task_struct *tsk) void vtime_account_user(struct task_struct *tsk) { - cputime_t delta_cpu; + cputime_t delta_time, steal_time; write_seqcount_begin(&tsk->vtime_seqcount); tsk->vtime_snap_whence = VTIME_SYS; if (vtime_delta(tsk)) { - delta_cpu = get_vtime_delta(tsk); - account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu)); + delta_time = get_vtime_delta(tsk); + steal_time = jiffies_to_cputime(steal_account_process_tick()); + + if (steal_time < delta_time) { + delta_time -= steal_time; + account_user_time(tsk, delta_time, cputime_to_scaled(delta_time)); + } } write_seqcount_end(&tsk->vtime_seqcount); } -- 1.9.1