From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932351AbcFHDGB (ORCPT ); Tue, 7 Jun 2016 23:06:01 -0400 Received: from mail-pa0-f65.google.com ([209.85.220.65]:34412 "EHLO mail-pa0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932119AbcFHDF6 (ORCPT ); Tue, 7 Jun 2016 23:05:58 -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 v5 3/3] sched/cputime: Add steal time support to full dynticks CPU time accounting Date: Wed, 8 Jun 2016 11:05:10 +0800 Message-Id: <1465355110-21714-3-git-send-email-wanpeng.li@hotmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1465355110-21714-1-git-send-email-wanpeng.li@hotmail.com> References: <1465355110-21714-1-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-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 --- v4 -> v5: * apply same logic to account_idle_time, so change get_vtime_delta instead 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 | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 75f98c5..b62f9f8 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; } /* @@ -681,12 +681,17 @@ static cputime_t vtime_delta(struct task_struct *tsk) static cputime_t get_vtime_delta(struct task_struct *tsk) { unsigned long now = READ_ONCE(jiffies); - unsigned long delta = now - tsk->vtime_snap; + cputime_t delta_time, steal_time; + steal_time = jiffies_to_cputime(steal_account_process_tick()); + delta_time = jiffies_to_cputime(now - tsk->vtime_snap); WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE); tsk->vtime_snap = now; - return jiffies_to_cputime(delta); + if (steal_time < delta_time) + delta_time -= steal_time; + + return delta_time; } static void __vtime_account_system(struct task_struct *tsk) -- 1.9.1