On 1/19/22 6:23 PM, Darrick J. Wong wrote: > From: Darrick J. Wong <djwong@xxxxxxxxxx> > > We have a handful of users who continually ping the maintainer with > questions about why pmem and dax don't work quite the way they want > (which is to say 2MB extents and PMD mappings) because they copy-pasted > some garbage from Google that's wrong. Encode the correct defaults into > a mkfs config file and ship that. > > Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx> > --- > mkfs/Makefile | 1 + > mkfs/dax_x86_64.conf | 19 +++++++++++++++++++ > 2 files changed, 20 insertions(+) > create mode 100644 mkfs/dax_x86_64.conf > > > diff --git a/mkfs/Makefile b/mkfs/Makefile > index 0aaf9d06..55d9362f 100644 > --- a/mkfs/Makefile > +++ b/mkfs/Makefile > @@ -10,6 +10,7 @@ LTCOMMAND = mkfs.xfs > HFILES = > CFILES = proto.c xfs_mkfs.c > CFGFILES = \ > + dax_x86_64.conf \ > lts_4.19.conf \ > lts_5.4.conf \ > lts_5.10.conf \ > diff --git a/mkfs/dax_x86_64.conf b/mkfs/dax_x86_64.conf > new file mode 100644 > index 00000000..bc3f3c9a > --- /dev/null > +++ b/mkfs/dax_x86_64.conf > @@ -0,0 +1,19 @@ > +# mkfs.xfs configuration file for persistent memory on x86_64. > +# Block size must match page size (4K) and we require V5 for the DAX inode > +# flag. Set extent size hints and stripe units to encourage the filesystem to > +# allocate PMD sized (2MB) blocks. > + > +[block] > +size=4096 > + > +[metadata] > +crc=1 > + > +[data] > +sunit=4096 > +swidth=4096 How would you feel about: su=2m sw=1 instead, because I think that explicit units are far more obvious than "4096 <handwave> 512-byte units" ? > +extszinherit=512 ... though I guess this can only be specified in fsblocks, LOLZ :( > +daxinherit=1 > + > +[realtime] > +extsize=2097152 Pretty weird to set this if you don't have a realtime device but I guess it works. -Eric
