Re: [PATCH] btrfs: don't loop again over pinned extent maps when shrinking extent maps

[Josef Bacik <josef@toxicpanda.com>]

On Mon, Jul 01, 2024 at 10:23:31AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> During extent map shrinking, while iterating over the extent maps of an
> inode, if we happen to find a lot of pinned extent maps and we need to
> reschedule, we'll start iterating the extent map tree from its first
> extent map. This can result in visiting the same extent maps again, and if
> they are not yet unpinned, we are just wasting time and can end up
> iterating over them again if we happen to reschedule again before finding
> an extent map that is not pinned - this could happen yet more times if the
> unpinning doesn't happen soon (at ordered extent completion).
> 
> So improve on this by starting on the next extent map everytime we need
> to reschedule. Any previously pinned extent maps we be checked again the
> next time the extent map shrinker is run (if needed).
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef