On Fri, Sep 15, 2023 at 07:45:11AM +1000, Dave Chinner wrote:
> On Thu, Sep 14, 2023 at 02:36:40PM +0200, cem@xxxxxxxxxx wrote:
> > From: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
> >
> > The current output message prints out a suggestion of an AG size to be
> > used in lieu of the user-defined one.
> > The problem is this suggestion is printed in filesystem blocks, while
> > agsize= option receives a size in bytes (or m, g).
>
> Hmmm. The actual definition of the parameter in mkfs.xfs has
> ".convert = true", which means it will take a value in filesystem
> blocks by appending "b" to the number.
>
> i.e. anything that is defined as a "value" with that supports a
> suffix like "m" or "g" requires conversion via cvtnum() to turn it
> into a byte-based units will also support suffixes for block and
> sector size units.
>
> Hence "-d agsize=10000b" will make an AG of 10000 filesystem blocks
> in size, or 40000kB in size if the block size 4kB....
Hah, I actually didn't realize the b suffix, knowing that now, I believe
we can just replace the message by:
"for example: agsize=%llub\n")".
I'd rather have it printed in FSblocks other than bytes anyway, giving the size
of the final number. I just opted for bytes originally, to avoid adding more
code just for calculating the representation on a bigger unit.
I'll send a V2.
Carlos
>
> # mkfs.xfs -f -dagsize=100000b /dev/vdb
> meta-data=/dev/vdb isize=512 agcount=42, agsize=100000 blks
> = sectsz=512 attr=2, projid32bit=1
> = crc=1 finobt=1, sparse=1, rmapbt=0
> = reflink=1 bigtime=1 inobtcount=1 nrext64=0
> data = bsize=4096 blocks=4194304, imaxpct=25
> = sunit=0 swidth=0 blks
> naming =version 2 bsize=4096 ascii-ci=0, ftype=1
> log =internal log bsize=4096 blocks=16384, version=2
> = sectsz=512 sunit=0 blks, lazy-count=1
> realtime =none extsz=4096 blocks=0, rtextents=0
> Discarding blocks...Done.
> #
>
> > This patch tries to make user's life easier by outputing the suggesting
> > in bytes directly.
> >
> > Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
> > ---
> > mkfs/xfs_mkfs.c | 8 +++++---
> > 1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> > index d3a15cf44..827d5b656 100644
> > --- a/mkfs/xfs_mkfs.c
> > +++ b/mkfs/xfs_mkfs.c
> > @@ -3179,9 +3179,11 @@ _("agsize rounded to %lld, sunit = %d\n"),
> > if (cli_opt_set(&dopts, D_AGCOUNT) ||
> > cli_opt_set(&dopts, D_AGSIZE)) {
> > printf(_(
> > -"Warning: AG size is a multiple of stripe width. This can cause performance\n\
> > -problems by aligning all AGs on the same disk. To avoid this, run mkfs with\n\
> > -an AG size that is one stripe unit smaller or larger, for example %llu.\n"),
> > +"Warning: AG size is a multiple of stripe width. This can cause performance\n\
> > +problems by aligning all AGs on the same disk. To avoid this, run mkfs with\n\
> > +an AG size that is one stripe unit smaller or larger,\n\
> > +for example: agsize=%llu (%llu blks).\n"),
> > + (unsigned long long)((cfg->agsize - dsunit) * cfg->blocksize),
> > (unsigned long long)cfg->agsize - dsunit);
> > fflush(stdout);
> > goto validate;
>
> I have no problem with the change, though I think the man page needs
> updating to remove the "takes a value in bytes" because it has taken
> a value that supports all the suffix types the man page defines
> for quite a long time....
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
