From 7cbbfd27a929398f027f0e8d01c80264f47db4e4 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 16 Jul 2025 14:54:06 +0200 Subject: [PATCH] xfs: improve the comments in xfs_max_open_zones Describe the rationale for the decisions a bit better. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Carlos Maiolino --- fs/xfs/xfs_zone_alloc.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/fs/xfs/xfs_zone_alloc.c b/fs/xfs/xfs_zone_alloc.c index 729d80ff52c14..6a123d3dd62d4 100644 --- a/fs/xfs/xfs_zone_alloc.c +++ b/fs/xfs/xfs_zone_alloc.c @@ -1114,24 +1114,27 @@ xfs_get_zone_info_cb( } /* - * Calculate the max open zone limit based on the of number of - * backing zones available + * Calculate the max open zone limit based on the of number of backing zones + * available. */ static inline uint32_t xfs_max_open_zones( struct xfs_mount *mp) { unsigned int max_open, max_open_data_zones; + /* - * We need two zones for every open data zone, - * one in reserve as we don't reclaim open zones. One data zone - * and its spare is included in XFS_MIN_ZONES. + * We need two zones for every open data zone, one in reserve as we + * don't reclaim open zones. One data zone and its spare is included + * in XFS_MIN_ZONES to support at least one user data writer. */ max_open_data_zones = (mp->m_sb.sb_rgcount - XFS_MIN_ZONES) / 2 + 1; max_open = max_open_data_zones + XFS_OPEN_GC_ZONES; /* - * Cap the max open limit to 1/4 of available space + * Cap the max open limit to 1/4 of available space. Without this we'd + * run out of easy reclaim targets too quickly and storage devices don't + * handle huge numbers of concurrent write streams overly well. */ max_open = min(max_open, mp->m_sb.sb_rgcount / 4); -- 2.47.2