Re: [PATCH 3/9] xfs: expose sysfs knob to control inode inactivation delay

[Dave Chinner <david@fromorbit.com>]

On Mon, Jun 07, 2021 at 03:25:10PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> Allow administrators to control the length that we defer inode
> inactivation.  By default we'll set the delay to 2 seconds, as an
> arbitrary choice between allowing for some batching of a deltree
> operation, and not letting too many inodes pile up in memory.
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  Documentation/admin-guide/xfs.rst |    7 +++++++
>  fs/xfs/xfs_globals.c              |    3 +++
>  fs/xfs/xfs_icache.c               |    3 ++-
>  fs/xfs/xfs_linux.h                |    1 +
>  fs/xfs/xfs_sysctl.c               |    9 +++++++++
>  fs/xfs/xfs_sysctl.h               |    1 +
>  6 files changed, 23 insertions(+), 1 deletion(-)
> 
> 
> diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst
> index f9b109bfc6a6..9dd62b155fda 100644
> --- a/Documentation/admin-guide/xfs.rst
> +++ b/Documentation/admin-guide/xfs.rst
> @@ -277,6 +277,13 @@ The following sysctls are available for the XFS filesystem:
>  	references and returns timed-out AGs back to the free stream
>  	pool.
>  
> +  fs.xfs.inode_gc_delay
> +	(Units: centiseconds   Min: 0  Default: 1  Max: 360000)
> +	The amount of time to delay cleanup work that happens after a file is
> +	closed by all programs.  This involves clearing speculative
> +	preallocations from linked files and freeing unlinked files.  A higher
> +	value here increases batching at a risk of background work storms.

Can we make new timers use a sane unit of time like milliseconds?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com