From patchwork Fri Mar 29 02:59:09 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chang-An Chen X-Patchwork-Id: 10876227 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 327A41669 for ; Fri, 29 Mar 2019 03:00:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 162F528E55 for ; Fri, 29 Mar 2019 03:00:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0785C28E49; Fri, 29 Mar 2019 03:00:18 +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=-5.0 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9063128E49 for ; Fri, 29 Mar 2019 03:00:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=wB+MF3zgoCmvqjBZ4vrutsVB3WeZV7X3RHY56JDMX9M=; b=G9DgIuhknid/6m m7EWF+sVNe+zZBMHStJ2EPoOQb5WEOERqExuo+PcGhRO1JVmE31qqMa96Fn2kCbswg/gLtD7AFfLY PcYLXWo+xq3Q29iz5k1r6U5BwukkT8kGKoK2IReAN47SAbv8aoyhEk7z959GqX0lQkLRo5OfaGSKa rQVMVDVmffGvo8/93tiR2K/ZaMnopXnmPFjh/eRk7kaCkXG7RHwLdCz71c0DIzpkp1K3LdDt4lzxd Z+pnjnUPXK1haV/VwGCBKzQ2HJ1wmpUIKBA9jbuc6s0hC8s/daQjlrQ070UnwcmLszbtWCqjya6HG a/7rSU+n/6Q30XfUIlNw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h9hkd-0001CP-Bc; Fri, 29 Mar 2019 03:00:15 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h9hkT-0000JY-Di; Fri, 29 Mar 2019 03:00:08 +0000 X-UUID: ef515b03c7154c018b63677d33946d3c-20190328 X-UUID: ef515b03c7154c018b63677d33946d3c-20190328 Received: from mtkcas68.mediatek.inc [(172.29.94.19)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLS) with ESMTP id 281505798; Thu, 28 Mar 2019 19:00:02 -0800 Received: from MTKMBS02N2.mediatek.inc (172.21.101.101) by MTKMBS62N2.mediatek.inc (172.29.193.42) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 28 Mar 2019 20:00:00 -0700 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs02n2.mediatek.inc (172.21.101.101) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 29 Mar 2019 10:59:52 +0800 Received: from mtkswgap22.mediatek.inc (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 29 Mar 2019 10:59:52 +0800 From: Chang-An Chen To: Frederic Weisbecker , Thomas Gleixner , Ingo Molnar , Matthias Brugger Subject: [PATCH v2] sched/clock: Prevent generic sched_clock wrap caused by tick_freeze() Date: Fri, 29 Mar 2019 10:59:09 +0800 Message-ID: <1553828349-8914-1-git-send-email-chang-an.chen@mediatek.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 X-TM-SNTS-SMTP: 37D2788DCE6E192A4D30B7F6CBA7ACA6C585B44012A8B55DF98EBFB5EB8A71DD2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190328_200005_488718_F09F37A1 X-CRM114-Status: GOOD ( 10.84 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Corey Minyard , freddy.hsin@mediatek.com, Chang-An Chen , Kees Cook , kuohong.wang@mediatek.com, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, John Stultz , Stanley Chu , linux-arm-kernel@lists.infradead.org Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+patchwork-linux-mediatek=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP tick_freeze() introduced by suspend-to-idle in commit 124cf9117c5f ("PM / sleep: Make it possible to quiesce timers during suspend-to-idle") will use timekeeping_suspend() instead of syscore_suspend() during suspend-to-idle. It means that generic sched_clock will keep going because sched_clock_suspend() and sched_clock_resume() are not taken during suspend-to-idle. This will lead to generic sched_clock wrap. For example: In my arm system with suspend-to-idle enabled, sched_clock is registered as "56 bits at 13MHz, resolution 76ns, wraps every 4398046511101ns", which means the real wrapping duration is 8796093022202ns. [ 134.551779] suspend-to-idle suspend (timekeeping_suspend()) [ 1204.912239] suspend-to-idle resume (timekeeping_resume()) ...... [ 1206.912239] suspend-to-idle suspend (timekeeping_suspend()) [ 5880.502807] suspend-to-idle resume (timekeeping_resume()) ...... [ 6000.403724] suspend-to-idle suspend (timekeeping_suspend()) [ 8035.753167] suspend-to-idle resume (timekeeping_resume()) ...... [ 8795.786684] (2)[321:charger_thread]...... [ 8795.788387] (2)[321:charger_thread]...... [ 0.057226] (0)[0:swapper/0]...... [ 0.061447] (2)[0:swapper/2]...... Sched_clock was not stopped during suspend-to-idle, and sched_clock_poll hrtimer was not expired because timekeeping_suspend() is taken during suspend-to-idle. It makes sched_clock wrap at kernel time 8796s. To fix this issue, we add sched_clock_suspend() and sched_clock_resume() in tick_freeze() together with timekeeping_suspend() and timekeeping_resume() to make sure generic sched_clock wrapping will not happen. Signed-off-by: Chang-An Chen Fixes: 124cf9117c5f (PM / sleep: Make it possible to quiesce timers during suspend-to-idle) --- kernel/time/sched_clock.c | 4 ++-- kernel/time/tick-common.c | 2 ++ kernel/time/timekeeping.h | 7 +++++++ 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c index 094b82c..930113b 100644 --- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -272,7 +272,7 @@ static u64 notrace suspended_sched_clock_read(void) return cd.read_data[seq & 1].epoch_cyc; } -static int sched_clock_suspend(void) +int sched_clock_suspend(void) { struct clock_read_data *rd = &cd.read_data[0]; @@ -283,7 +283,7 @@ static int sched_clock_suspend(void) return 0; } -static void sched_clock_resume(void) +void sched_clock_resume(void) { struct clock_read_data *rd = &cd.read_data[0]; diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 529143b..df40146 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -487,6 +487,7 @@ void tick_freeze(void) trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), true); system_state = SYSTEM_SUSPEND; + sched_clock_suspend(); timekeeping_suspend(); } else { tick_suspend_local(); @@ -510,6 +511,7 @@ void tick_unfreeze(void) if (tick_freeze_depth == num_online_cpus()) { timekeeping_resume(); + sched_clock_resume(); system_state = SYSTEM_RUNNING; trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), false); diff --git a/kernel/time/timekeeping.h b/kernel/time/timekeeping.h index 7a9b4eb..141ab3a 100644 --- a/kernel/time/timekeeping.h +++ b/kernel/time/timekeeping.h @@ -14,6 +14,13 @@ extern ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, extern void timekeeping_warp_clock(void); extern int timekeeping_suspend(void); extern void timekeeping_resume(void); +#ifdef CONFIG_GENERIC_SCHED_CLOCK +extern int sched_clock_suspend(void); +extern void sched_clock_resume(void); +#else +static inline int sched_clock_suspend(void) { return 0; } +static inline void sched_clock_resume(void) { } +#endif extern void do_timer(unsigned long ticks); extern void update_wall_time(void);