Re: [PATCH 1/2] xfs/558: scale blk IO size based on the filesystem blksz

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Jan 22, 2024 at 06:23:16PM +0100, Pankaj Raghav wrote:
> On 22/01/2024 17:53, Darrick J. Wong wrote:
> > On Mon, Jan 22, 2024 at 12:17:50PM +0100, Pankaj Raghav (Samsung) wrote:
> >> From: Pankaj Raghav <p.raghav@samsung.com>
> >>
> >> This test fails for >= 64k filesystem block size on a 4k PAGE_SIZE
> >> system(see LBS efforts[1]). Scale the `blksz` based on the filesystem
> > > Fails how, specifically?
> 
> I basically get this in 558.out.bad when I set filesystem block size to be 64k:
> QA output created by 558
> Expected to hear about writeback iomap invalidations?
> Silence is golden
> 
> But I do see that iomap invalidations are happening for 16k and 32k, which makes it pass
> the test for those block sizes.
> 
> My suspicion was that we don't see any invalidations because of the blksz fixed
> at 64k in the test, which will contain one FSB in the case of 64k block size.
> 
> Let me know if I am missing something.

Nope, that sounds good and fixes the problems I saw.  So:
Tested-by: Darrick J. Wong <djwong@kernel.org>

And if you add to the commit message that this test specifically fixes
the "Expected to hear about writeback iomap invalidations?" message for
64k filesystems, then:
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> > 
> > --D
> > 
> >> block size instead of fixing it as 64k so that we do get some iomap
> >> invalidations while doing concurrent writes.
> >>
> >> Cap the blksz to be at least 64k to retain the same behaviour as before
> >> for smaller filesystem blocksizes.
> >>
> >> [1] LBS effort: https://lore.kernel.org/lkml/20230915183848.1018717-1-kernel@pankajraghav.com/
> >>
> >> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> >> ---
> >>  tests/xfs/558 | 7 ++++++-
> >>  1 file changed, 6 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/tests/xfs/558 b/tests/xfs/558
> >> index 9e9b3be8..270f458c 100755
> >> --- a/tests/xfs/558
> >> +++ b/tests/xfs/558
> >> @@ -127,7 +127,12 @@ _scratch_mount >> $seqres.full
> >>  $XFS_IO_PROG -c 'chattr -x' $SCRATCH_MNT &> $seqres.full
> >>  _require_pagecache_access $SCRATCH_MNT
> >>  
> >> -blksz=65536
> >> +min_blksz=65536
> >> +file_blksz=$(_get_file_block_size "$SCRATCH_MNT")
> >> +blksz=$(( 8 * $file_blksz ))
> >> +
> >> +blksz=$(( blksz > min_blksz ? blksz : min_blksz ))
> >> +
> >>  _require_congruent_file_oplen $SCRATCH_MNT $blksz
> >>  
> >>  # Make sure we have sufficient extent size to create speculative CoW
> >> -- 
> >> 2.43.0
> >>
>