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Date:   Fri, 30 Nov 2018 08:49:20 -0800
From:   "Paul E. McKenney" <paulmck@linux.ibm.com>
To:     "He, Bo" <bo.he@intel.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "josh@joshtriplett.org" <josh@joshtriplett.org>,
        "mathieu.desnoyers@efficios.com" <mathieu.desnoyers@efficios.com>,
        "jiangshanlai@gmail.com" <jiangshanlai@gmail.com>,
        "Zhang, Jun" <jun.zhang@intel.com>,
        "Xiao, Jin" <jin.xiao@intel.com>,
        "Zhang, Yanmin" <yanmin.zhang@intel.com>
Subject: Re: rcu_preempt caused oom
Reply-To: paulmck@linux.ibm.com
References: <CD6925E8781EFD4D8E11882D20FC406D52A11F61@SHSMSX104.ccr.corp.intel.com>
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 <20181130144317.GQ4170@linux.ibm.com>
 <20181130101631.618d955f@gandalf.local.home>
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On Fri, Nov 30, 2018 at 03:18:58PM +0000, He, Bo wrote:
> Here is the kernel cmdline:

Thank you!

> Kernel command line: androidboot.acpio_idx=0  androidboot.bootloader=efiwrapper-02_03-userdebug_kernelflinger-06_03-userdebug androidboot.diskbus=00.0 androidboot.verifiedbootstate=green androidboot.bootreason=power-on androidboot.serialno=R1J56L6006a7bb g_ffs.iSerialNumber=R1J56L6006a7bb no_timer_check noxsaves reboot_panic=p,w i915.hpd_sense_invert=0x7 mem=2G nokaslr nopti ftrace_dump_on_oops trace_buf_size=1024K intel_iommu=off gpt loglevel=4 androidboot.hardware=gordon_peak firmware_class.path=/vendor/firmware relative_sleep_states=1 enforcing=0 androidboot.selinux=permissive cpu_init_udelay=10 androidboot.android_dt_dir=/sys/bus/platform/devices/ANDR0001:00/properties/android/ pstore.backend=ramoops memmap=0x1400000$0x50000000 ramoops.mem_address=0x50000000 ramoops.mem_size=0x1400000 ramoops.record_size=0x4000 ramoops.console_size=0x1000000 ramoops.ftrace_size=0x10000 ramoops.dump_oops=1 vga=current 
> i915.modeset=1 drm.atomic=1 i915.nuclear_pageflip=1 drm.vblankoffdelay=

And no sign of any suppression of RCU CPU stall warnings.  Hmmm...
It does take more than 21 seconds to OOM?  Or do things happen faster
than that?  If they do happen faster than that, then on approach would
be to add something like this to the kernel command line:

	rcupdate.rcu_cpu_stall_timeout=7

This would set the stall timeout to seven seconds.  Note that timeouts
less than three seconds are silently interpreted as three seconds.

							Thanx, Paul

> -----Original Message-----
> From: Steven Rostedt <rostedt@goodmis.org> 
> Sent: Friday, November 30, 2018 11:17 PM
> To: Paul E. McKenney <paulmck@linux.ibm.com>
> Cc: He, Bo <bo.he@intel.com>; linux-kernel@vger.kernel.org; josh@joshtriplett.org; mathieu.desnoyers@efficios.com; jiangshanlai@gmail.com; Zhang, Jun <jun.zhang@intel.com>; Xiao, Jin <jin.xiao@intel.com>; Zhang, Yanmin <yanmin.zhang@intel.com>
> Subject: Re: rcu_preempt caused oom
> 
> On Fri, 30 Nov 2018 06:43:17 -0800
> "Paul E. McKenney" <paulmck@linux.ibm.com> wrote:
> 
> > Could you please send me your list of kernel boot parameters?  They 
> > usually appear near the start of your console output.
> 
> Or just: cat /proc/cmdline
> 
> -- Steve
>