[15] RFR: 8236595: Add more comments about how to setup simulated NVRAM before run java/nio/MappedByteBuffer/PmemTest.java

[Chris Yin]

Thank you Andrew. Pushed.

Regards,
Chris

> On 3 Jan 2020, at 6:49 PM, Andrew Dinn <adinn at redhat.com> wrote:
> 
> Hi Chris,
> 
> On 02/01/2020 17:49, Alan Bateman wrote:
>> Looks okay to me but probably best if Andrew Dinn reviews (as the test
>> is part of JEP 352).
> 
> Yes, thanks for making this improvement, Chris (especially removing the
> spurious wildcard arg to nodectl). The patch is fine by me.
> 
> regards,
> 
> 
> Andrew Dinn
> -----------
> Senior Principal Software Engineer
> Red Hat UK Ltd
> Registered in England and Wales under Company Registration No. 03798903
> Directors: Michael Cunningham, Michael ("Mike") O'Neill
> 
>> On 31/12/2019 05:18, Chris Yin wrote:
>>> Please have a review for below comments change only to manual test
>>> java/nio/MappedByteBuffer/PmemTest.java, the motivation is to make the
>>> pre-config steps for setup simulated NVRAM device more clear to
>>> newbie, thanks
>>> 
>>> JBS Issue: https://bugs.openjdk.java.net/browse/JDK-8236595
>>> Webrev: http://cr.openjdk.java.net/~xyin/8236595/webrev.00/
>>> 
>>> 
>>> Patch:
>>> --- old/test/jdk/java/nio/MappedByteBuffer/PmemTest.java    2019-12-31
>>> 12:47:34.000000000 +0800
>>> +++ new/test/jdk/java/nio/MappedByteBuffer/PmemTest.java    2019-12-31
>>> 12:47:34.000000000 +0800
>>> @@ -50,10 +50,20 @@
>>>    *
>>>    *
>>> https://developers.redhat.com/blog/2016/12/05/configuring-and-using-persistent-memory-rhel-7-3/
>>> 
>>>    * https://nvdimm.wiki.kernel.org/
>>> - * TL;DR: add "memmap=1G!4G" to /etc/default/grub,
>>> - *        then grub2-mkconfig -o /boot/grub2/grub.cfg and reboot
>>> + * TL;DR: add "memmap=1G!4G" to /etc/default/grub, eg.
>>> GRUB_CMDLINE_LINUX="memmap=1G!4G"
>>> + *        then ("sudo" may required)
>>> + *          for RHEL(BIOS-based): grub2-mkconfig -o /boot/grub2/grub.cfg
>>> + *          for RHEL(UEFI-based): grub2-mkconfig -o
>>> /boot/efi/EFI/redhat/grub.cfg
>>> + *          for Ubuntu: update-grub2
>>> + *        finally reboot
>>> + *        after the host been rebooted, a new /dev/pmem{N} device
>>> should exist,
>>> + *        naming conversion starts at /dev/pmem0
>>> + *
>>> + *  Prepare test directory follow below commands, "sudo" may required
>>> + *  (if ndctl or mkfs.xfs not exist, install ndctl or xfsprogs
>>> package first)
>>> + *  (for RHEL8, when call mkfs.xfs, specify the -m reflink=0 option
>>> to disable reflink feature)
>>>    *
>>> - *  ndctl create-namespace  * -f -e namespace0.0 -m memory -M mem
>>> + *  ndctl create-namespace -f -e namespace0.0 -m memory -M mem
>>>    *  mkdir /mnt/pmem
>>>    *  mkfs.xfs -f /dev/pmem0; mount -o dax /dev/pmem0 /mnt/pmem/
>>>    *  mkdir /mnt/pmem/test; chmod a+rwx /mnt/pmem/test
>>> 
>>> Regards,
>>> Chris
>>> 
>