From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933069AbcFTSVT (ORCPT ); Mon, 20 Jun 2016 14:21:19 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52563 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932992AbcFTSVJ (ORCPT ); Mon, 20 Jun 2016 14:21:09 -0400 X-IBM-Helo: d01dlp01.pok.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com Date: Mon, 20 Jun 2016 11:21:05 -0700 From: "Paul E. McKenney" To: Arnd Bergmann Cc: Boqun Feng , Josh Triplett , linux-kernel@vger.kernel.org Subject: Re: [PATCH] torture: use ktime_t consistently Reply-To: paulmck@linux.vnet.ibm.com References: <20160620155651.2497676-1-arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160620155651.2497676-1-arnd@arndb.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16062018-0040-0000-0000-0000009CE808 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16062018-0041-0000-0000-00000476D0A3 Message-Id: <20160620182105.GV3923@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-20_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606200200 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 20, 2016 at 05:56:40PM +0200, Arnd Bergmann wrote: > A recent change accidentally introduced a 64-bit division in torture_shutdown, > which fails to build on 32-bit architectures: > > kernel/built-in.o: In function `torture_shutdown': > :(.text+0x4b29a): undefined reference to `__aeabi_uldivmod' > > This converts the function to use ktime_t instead, which also simplifies > it a little. > > Signed-off-by: Arnd Bergmann > Fixes: b4aa201e0c7c ("torture: Convert torture_shutdown() to hrtimer") Thank you, Arnd! I ended up squashing in the alternative change below before I saw your email address. This is currently untested, so I might well end up using yours instead should breakage ensue. Given that I haven't done much with ktime_t, breakage is rather likely. Thoughts? Thanx, Paul ------------------------------------------------------------------------ commit 303c4c9474e84112ab2474cd383282f5dbfc75c3 Author: Paul E. McKenney Date: Sat Jun 18 07:45:43 2016 -0700 torture: Convert torture_shutdown() to hrtimer Upcoming changes to the timer wheel introduce significant inaccuracy and possibly also an ultimate limit on timeout duration. This is a problem for the current implementation of torture_shutdown() because (1) shutdown times are user-specified, and can therefore be quite long, and (2) the torture scripting will kill a test instance that runs for more than a few minutes longer than scheduled. This commit therefore converts the torture_shutdown() timed waits to an hrtimer. Signed-off-by: Paul E. McKenney diff --git a/kernel/torture.c b/kernel/torture.c index 75961b3decfe..1c1b5960d27f 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -446,9 +447,9 @@ EXPORT_SYMBOL_GPL(torture_shuffle_cleanup); * Variables for auto-shutdown. This allows "lights out" torture runs * to be fully scripted. */ -static int shutdown_secs; /* desired test duration in seconds. */ +static ktime_t shutdown_ms; /* desired test duration in seconds. */ static struct task_struct *shutdown_task; -static unsigned long shutdown_time; /* jiffies to system shutdown. */ +static ktime_t shutdown_time; /* jiffies to system shutdown. */ static void (*torture_shutdown_hook)(void); /* @@ -471,20 +472,21 @@ EXPORT_SYMBOL_GPL(torture_shutdown_absorb); */ static int torture_shutdown(void *arg) { - long delta; - unsigned long jiffies_snap; + ktime_t delta; + ktime_t ktime_snap; VERBOSE_TOROUT_STRING("torture_shutdown task started"); - jiffies_snap = jiffies; - while (ULONG_CMP_LT(jiffies_snap, shutdown_time) && + ktime_snap = ktime_get(); + while (ktime_before(ktime_snap, shutdown_time) && !torture_must_stop()) { - delta = shutdown_time - jiffies_snap; + delta = ktime_sub(shutdown_time, ktime_snap); if (verbose) pr_alert("%s" TORTURE_FLAG - "torture_shutdown task: %lu jiffies remaining\n", - torture_type, delta); - schedule_timeout_interruptible(delta); - jiffies_snap = jiffies; + "torture_shutdown task: %llu ms remaining\n", + torture_type, ktime_to_ms(delta)); + set_current_state(TASK_INTERRUPTIBLE); + schedule_hrtimeout(&delta, HRTIMER_MODE_REL); + ktime_snap = ktime_get(); } if (torture_must_stop()) { torture_kthread_stopping("torture_shutdown"); @@ -511,10 +513,10 @@ int torture_shutdown_init(int ssecs, void (*cleanup)(void)) { int ret = 0; - shutdown_secs = ssecs; torture_shutdown_hook = cleanup; - if (shutdown_secs > 0) { - shutdown_time = jiffies + shutdown_secs * HZ; + if (ssecs > 0) { + shutdown_ms = ms_to_ktime(ssecs * 1000ULL); + shutdown_time = ktime_add(ktime_get(), shutdown_ms); ret = torture_create_kthread(torture_shutdown, NULL, shutdown_task); }