On Fri, Feb 25, 2022 at 04:21:59PM -0600, Eric Sandeen wrote: > 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" ? Fine with me. :) > > +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. Yeah, everything rt is weird. :) --D > > -Eric
