On 7/17/2021 2:54 PM, Sierra Guiza, Alejandro (Alex) wrote:

On 7/16/2021 5:14 PM, Felix Kuehling wrote:

quoted

Am 2021-07-16 um 11:07 a.m. schrieb Theodore Y. Ts'o:

quoted

On Wed, Jun 23, 2021 at 05:49:55PM -0400, Felix Kuehling wrote:

quoted

I can think of two ways to test the changes for 
MEMORY_DEVICE_GENERIC in
this patch series in a way that is reproducible without special 
hardware and
firmware:

For the reference counting changes we could use the dax driver with 
hmem and
use efi_fake_mem on the kernel command line to create some 
DEVICE_GENERIC
pages. I'm open to suggestions for good user mode tests to exercise 
dax
functionality on this type of memory.

Sorry for the thread necromancy, but now that the merge window is
past....

No worries. Alejandro should have a new version of this series in a few
days, with updates to hmm_test and some fixes.

V4 patch series have been sent for review.
https://marc.info/?l=dri-devel&m=162654971618911&w=2

Regards,
Alex Sierra

quoted

quoted

Today I test ext4's dax support, without having any $$$ DAX hardware,
by using the kernel command line "memmap=4G!9G:memmap=9G!14G" which
reserves memory so that creates two pmem device and then I run
xfstests with DAX enabled using qemu or using a Google Compute Engine
VM, using TEST_DEV=/dev/pmem0 and SCRATCH_DEV=/dev/pmem1.

If you can give me a recipe for what kernel configs I should enable,
and what magic kernel command line arguments to use, then I'd be able
to test your patch set with ext4.

That would be great!

Regarding kernel config options, it should be the same as what you're
using for DAX testing today. We're not changing or adding any Kconfig
options. But let me take a stab:

ZONE_DEVICE
HMM_MIRROR
MMU_NOTIFIER
DEVICE_PRIVATE (maybe not needed for your test)
FS_DAX

Hi Theodore,
I wonder if you had chance to set the kernel configs from Felix to 
enable DAX in xfstests.

I've been trying to test FS DAX on my side using virtio-fs + QEMU. 
Unfortunately, Im having some problems setting up the environment with 
the guest kernel. Could you share your VM (QEMU or GCE) setup to run it 
with xfstests?

Regards,
Alex S.

quoted

I'm not sure what you're looking for in terms of kernel command line,
other than the memmap options you already found. There are some more
options to run hmm_test with fake SPM (DEVICE_GENERIC) memory, but we're
already running that ourselves. That will also be in the next revision
of this patch series.

In order to run hmm test with generic device type enabled, set the 
following:

kernel config:
EFI_FAKE_MEMMAP
RUNTIME_TESTING_MENU
TEST_HMM=m

Kernel parameters to fake SP memory. The addresses set here are based 
on my system's usable memory enumerated by BIOS-e820 at boot. The test 
requires two SP devices of at least 256MB.
efi_fake_mem=1G@0x100000000:0x40000,1G@0x140000000:0x40000

To run the hmm_test in generic device type pass the SP addresses to 
the sh script.
sudo ./test_hmm.sh smoke 0x100000000 0x140000000

quoted

If you can run your xfstests with DAX on top of this patch series, that
would be very helpful. That's to make sure the ZONE_DEVICE page refcount
changes don't break DAX.

Regards,
   Felix

quoted

Cheers,

                        - Ted