Re: [PATCH v2] xfs: cache open zone in inode->i_private

[Damien Le Moal <dlemoal@kernel.org>]

On 10/17/25 12:55, Christoph Hellwig wrote:
> The MRU cache for open zones is unfortunately still not ideal, as it can
> time out pretty easily when doing heavy I/O to hard disks using up most
> or all open zones.  One option would be to just increase the timeout,
> but while looking into that I realized we're just better off caching it
> indefinitely as there is no real downside to that once we don't hold a
> reference to the cache open zone.
> 
> So switch the open zone to RCU freeing, and then stash the last used
> open zone into inode->i_private.  This helps to significantly reduce
> fragmentation by keeping I/O localized to zones for workloads that
> write using many open files to HDD.
> 
> Fixes: 4e4d52075577 ("xfs: add the zoned space allocator")
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Tested-by: Damien Le Moal <dlemoal@kernel.org>

-- 
Damien Le Moal
Western Digital Research