diff mbox series

[v3,2/3] docs/nvdimm: add description of alignment requirement of device dax

Message ID 20200429085011.63752-3-jingqi.liu@intel.com
State New
Headers show
Series fetch the alignment of device dax | expand

Commit Message

Liu, Jingqi April 29, 2020, 8:50 a.m. UTC 
For device dax (e.g., /dev/dax0.0), the NUM of 'align=NUM' option
needs to match the alignment requirement of the device dax.
It must be larger than or equal to the 'align' of device dax.

Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
---
 docs/nvdimm.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
index 362e99109e..c2c6e441b3 100644
--- a/docs/nvdimm.txt
+++ b/docs/nvdimm.txt
@@ -132,6 +132,16 @@  address to the page size (getpagesize(2)) by default. However, some
 types of backends may require an alignment different than the page
 size. In that case, QEMU v2.12.0 and later provide 'align' option to
 memory-backend-file to allow users to specify the proper alignment.
+For device dax (e.g., /dev/dax0.0), this alignment needs to match the
+alignment requirement of the device dax. The NUM of 'align=NUM' option
+must be larger than or equal to the 'align' of device dax.
+We can use one of the following commands to show the 'align' of device dax.
+
+    ndctl list -X
+    daxctl list -R
+
+In order to get the proper 'align' of device dax, you need to install
+the library 'libdaxctl'.
 
 For example, device dax require the 2 MB alignment, so we can use
 following QEMU command line options to use it (/dev/dax0.0) as the