On 10/13/2015 12:36 AM, Dan Williams wrote:
On Sun, Oct 11, 2015 at 9:33 PM, Xiao Guangrong
<guangrong.xiao@xxxxxxxxxxxxxxx> wrote:
On 10/11/2015 05:17 AM, Dan Williams wrote:
On Sat, Oct 10, 2015 at 8:52 PM, Xiao Guangrong
<guangrong.xiao@xxxxxxxxxxxxxxx> wrote:
[..]
====== Test ======
In host
1) create memory backed file, e.g # dd if=zero of=/tmp/nvdimm bs=1G
count=10
2) append "-object memory-backend-file,share,id=mem1,
mem-path=/tmp/nvdimm -device nvdimm,memdev=mem1,reserve-label-data,
id=nv1" in QEMU command line
In guest, download the latest upsteam kernel (4.2 merge window) and
enable
ACPI_NFIT, LIBNVDIMM and BLK_DEV_PMEM.
1) insmod drivers/nvdimm/libnvdimm.ko
2) insmod drivers/acpi/nfit.ko
3) insmod drivers/nvdimm/nd_btt.ko
4) insmod drivers/nvdimm/nd_pmem.ko
You can see the whole nvdimm device used as a single namespace and
/dev/pmem0
appears. You can do whatever on /dev/pmem0 including DAX access.
Currently Linux NVDIMM driver does not support namespace operation on
this
kind of PMEM, apply below changes to support dynamical namespace:
@@ -798,7 +823,8 @@ static int acpi_nfit_register_dimms(struct
acpi_nfit_desc *a
continue;
}
- if (nfit_mem->bdw && nfit_mem->memdev_pmem)
+ //if (nfit_mem->bdw && nfit_mem->memdev_pmem)
+ if (nfit_mem->memdev_pmem)
flags |= NDD_ALIASING;
This is just for testing purposes, right? I expect guests can
It's used to validate NVDIMM _DSM method and static namespace following
NVDIMM specs...
Static namespaces can be emitted without a label. Linux needs this to
support existing "label-less" bare metal NVDIMMs.
This is Linux specific? As i did not see it has been documented in the
spec...
sub-divide persistent memory capacity by partitioning the resulting
block device(s).
I understand that it's a Linux design... Hmm, can the same expectation
apply to PBLK?
BLK-mode is a bit different as those namespaces have both configurable
sector-size and an optional BTT. It is possible to expect multiple
BLK namespaces per a given region with different settings.
Okay, thanks for your nice explanation, Dan!
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