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

[Andrew Dinn]

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
>>