From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YmTcW-0005iK-P8 for user-mode-linux-devel@lists.sourceforge.net; Sun, 26 Apr 2015 20:57:44 +0000 Received: from www17.your-server.de ([213.133.104.17]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1YmTcU-0006Ov-1e for user-mode-linux-devel@lists.sourceforge.net; Sun, 26 Apr 2015 20:57:44 +0000 Message-ID: <1430081853.603436.7.camel@m3y3r.de> From: Thomas Meyer Date: Sun, 26 Apr 2015 22:57:33 +0200 In-Reply-To: References: <5444DC3F.20601@nod.at> <1429905520.157088.6.camel@m3y3r.de> Mime-Version: 1.0 List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net Subject: Re: [uml-devel] [UM] Long loop in __getnsdayoftime() after resume from ram To: Richard Weinberger Cc: Linux Kernel Mailing List , user-mode-linux-devel Am Sonntag, den 26.04.2015, 20:32 +0200 schrieb Richard Weinberger: > On Fri, Apr 24, 2015 at 9:58 PM, Thomas Meyer wrote: > > Am Montag, den 20.10.2014, 11:56 +0200 schrieb Richard Weinberger: > >> Am 20.10.2014 um 11:51 schrieb Thomas Meyer: > >> >> Hmm, does this always happen? > >> > > >> > Yes, my single core system seems to trigger this every time after resume from ram. > >> > >> What is your host kernel? > >> > >> >> At least on my notebook it did not happen. I've started an UML yesterday > >> >> suspended it and after more than 12h it worked fine today. > >> >> > >> >> BTW: Do you see the issue also then freezing UML using the freezer cgroup? > >> > > >> > I'm not sure what do you mean by this. Do I need to enable some special configs for this in the host or uml kernel? > >> > >> Create on the host side a new freezer cgroup, put UML into it and freeze/thaw it. > >> i.e. mkdir /sys/fs/cgroup/freezer/uml ; echo > /sys/fs/cgroup/freezer/uml/tasks. > >> In the said shell run UML and then freeze it using echo FROZEN > /sys/fs/cgroup/freezer/uml/freezer.state. > >> Later thaw it: echo THAWED > /sys/fs/cgroup/freezer/uml/freezer.state > >> > > > > Sadly, this also happens with a cgroup freezer group :-( > > > > bt > > #0 __iter_div_u64_rem (remainder=, divisor=, dividend=14641577537827850536) at include/linux/math64.h:12 > > 7 > > #1 timespec_add_ns (ns=, a=) at include/linux/time.h:235 > > #2 __getnstimeofday64 (ts=0xffffffffffffffff) at kernel/time/timekeeping.c:658 > > #3 0x0000000060098a00 in getnstimeofday64 (ts=) at kernel/time/timekeeping.c:678 > > #4 0x0000000060098a4c in do_gettimeofday (tv=0xab359e50) at kernel/time/timekeeping.c:897 > > #5 0x0000000060090d66 in SYSC_gettimeofday (tz=, tv=) at kernel/time/time.c:107 > > #6 SyS_gettimeofday (tv=-1, tz=2097152000) at kernel/time/time.c:102 > > #7 0x0000000060032cf3 in handle_syscall (r=0xa39db9e8) at arch/um/kernel/skas/syscall.c:35 > > #8 0x000000006004a247 in handle_trap (local_using_sysemu=, regs=, pid=) at arch/um/os-Lin > > ux/skas/process.c:174 > > #9 userspace (regs=0xa39db9e8) at arch/um/os-Linux/skas/process.c:399 > > #10 0x000000006002f125 in fork_handler () at arch/um/kernel/process.c:149 > > #11 0x0000000000000000 in ?? () > > > > It seems as only very few people running UML kernels and suspend their host systems... > > > > Any ideas? > > Can you give the attached patch a try? > Let's see if it proves my theory. > Looks like UML's clocksource needs fixing. Hi Richard, I did run this for an hour and did 4 suspend/resume cycles and it seems not to hang any more! I'll test your other patch the next week, but AFAIU using clock_gettime should solve this hangs in a sane way. Thanks for your support. kind regards thomas ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel