Re: [PATCH] common/xfs: Execute _xfs_check only for block size <= 4k

[Christoph Hellwig <hch@infradead.org>]

On Tue, Mar 24, 2020 at 09:17:29AM +0530, Chandan Rajendra wrote:
> fsstress when executed as part of some of the tests (e.g. generic/270)
> invokes chown() syscall many times by passing random integers as value
> for the uid argument. For each such syscall invocation for which there
> is no on-disk quota block, xfs invokes xfs_dquot_disk_alloc() which
> allocates a new block and instantiates all the quota structures mapped
> by the newly allocated block. For a single 64k block, the number of
> on-disk quota structures thus created will be 16 times more than that
> for a 4k block.
> 
> xfs_db's check command (executed after test script finishes execution)
> will read in all of the on-disk quota structures into memory. This
> causes the OOM event to be triggered when reading from filesystems with
> 64k block size. For machines with sufficiently large amount of system
> memory, this causes the test to execute for a very long time.
> 
> Due to the above stated reasons, this commit disables execution of
> xfs_db's check command when working on 64k blocksized filesystem.

Due to all the scalability issues in the xfs_db check command I think
it finally is time to just not run it by default at all.