On Sat, Sep 02, 2023 at 03:08:02AM +0800, Zorro Lang wrote:
> On Tue, Aug 29, 2023 at 04:03:49PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@xxxxxxxxxx>
> >
> > The write invalidation code in iomap can only be triggered for writes
> > that span multiple folios. If the kernel reports a huge page size,
> > scale up the write size.
> >
> > Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
> > ---
> > tests/xfs/559 | 29 ++++++++++++++++++++++++++++-
> > 1 file changed, 28 insertions(+), 1 deletion(-)
> >
> >
> > diff --git a/tests/xfs/559 b/tests/xfs/559
> > index cffe5045a5..64fc16ebfd 100755
> > --- a/tests/xfs/559
> > +++ b/tests/xfs/559
> > @@ -42,11 +42,38 @@ $XFS_IO_PROG -c 'chattr -x' $SCRATCH_MNT &> $seqres.full
> > _require_pagecache_access $SCRATCH_MNT
> >
> > blocks=10
> > -blksz=$(_get_page_size)
> > +
> > +# If this kernel advertises huge page support, it's possible that it could be
> > +# using large folios for the page cache writes. It is necessary to write
> > +# multiple folios (large or regular) to triggering the write invalidation,
> > +# so we'll scale the test write size accordingly.
> > +blksz=$(_get_hugepagesize)
>
> Isn't _require_hugepages needed if _get_hugepagesize is used?
Nope -- if the kernel doesn't support hugepages, then _get_hugepagesize
returns the empty string...
> Thanks,
> Zorro
>
> > +base_pagesize=$(_get_page_size)
> > +test -z "$blksz" && blksz=${base_pagesize}
...and this line will substitute in the base page size as the block size.
--D
> > filesz=$((blocks * blksz))
> > dirty_offset=$(( filesz - 1 ))
> > write_len=$(( ( (blocks - 1) * blksz) + 1 ))
> >
> > +# The write invalidation that we're testing below can only occur as part of
> > +# a single large write. The kernel limits writes to one base page less than
> > +# 2GiB to prevent lengthy IOs and integer overflows. If the block size is so
> > +# huge (e.g. 512M huge pages on arm64) that we'd exceed that, reduce the number
> > +# of blocks to get us under the limit.
> > +max_writesize=$((2147483647 - base_pagesize))
> > +if ((write_len > max_writesize)); then
> > + blocks=$(( ( (max_writesize - 1) / blksz) + 1))
> > + # We need at least three blocks in the file to test invalidation
> > + # between writes to multiple folios. If we drop below that,
> > + # reconfigure ourselves with base pages and hope for the best.
> > + if ((blocks < 3)); then
> > + blksz=$base_pagesize
> > + blocks=10
> > + fi
> > + filesz=$((blocks * blksz))
> > + dirty_offset=$(( filesz - 1 ))
> > + write_len=$(( ( (blocks - 1) * blksz) + 1 ))
> > +fi
> > +
> > # Create a large file with a large unwritten range.
> > $XFS_IO_PROG -f -c "falloc 0 $filesz" $SCRATCH_MNT/file >> $seqres.full
> >
> >
>
