From f3e2e53823b98d55da46ea72d32ac18bd7709c33 Mon Sep 17 00:00:00 2001 From: Hans Holmberg Date: Wed, 14 May 2025 10:50:37 +0000 Subject: [PATCH] xfs: add inode to zone caching for data placement Placing data from the same file in the same zone is a great heuristic for reducing write amplification and we do this already - but only for sequential writes. To support placing data in the same way for random writes, reuse the xfs mru cache to map inodes to open zones on first write. If a mapping is present, use the open zone for data placement for this file until the zone is full. Signed-off-by: Hans Holmberg Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Carlos Maiolino --- fs/xfs/xfs_mount.h | 1 + fs/xfs/xfs_zone_alloc.c | 109 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 110 insertions(+) diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 89965b7ac29c..d85084f9f317 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -236,6 +236,7 @@ typedef struct xfs_mount { bool m_update_sb; /* sb needs update in mount */ unsigned int m_max_open_zones; unsigned int m_zonegc_low_space; + struct xfs_mru_cache *m_zone_cache; /* Inode to open zone cache */ /* max_atomic_write mount option value */ unsigned long long m_awu_max_bytes; diff --git a/fs/xfs/xfs_zone_alloc.c b/fs/xfs/xfs_zone_alloc.c index d509e49b2aaa..80add26c0111 100644 --- a/fs/xfs/xfs_zone_alloc.c +++ b/fs/xfs/xfs_zone_alloc.c @@ -24,6 +24,7 @@ #include "xfs_zone_priv.h" #include "xfs_zones.h" #include "xfs_trace.h" +#include "xfs_mru_cache.h" void xfs_open_zone_put( @@ -796,6 +797,100 @@ xfs_submit_zoned_bio( submit_bio(&ioend->io_bio); } +/* + * Cache the last zone written to for an inode so that it is considered first + * for subsequent writes. + */ +struct xfs_zone_cache_item { + struct xfs_mru_cache_elem mru; + struct xfs_open_zone *oz; +}; + +static inline struct xfs_zone_cache_item * +xfs_zone_cache_item(struct xfs_mru_cache_elem *mru) +{ + return container_of(mru, struct xfs_zone_cache_item, mru); +} + +static void +xfs_zone_cache_free_func( + void *data, + struct xfs_mru_cache_elem *mru) +{ + struct xfs_zone_cache_item *item = xfs_zone_cache_item(mru); + + xfs_open_zone_put(item->oz); + kfree(item); +} + +/* + * Check if we have a cached last open zone available for the inode and + * if yes return a reference to it. + */ +static struct xfs_open_zone * +xfs_cached_zone( + struct xfs_mount *mp, + struct xfs_inode *ip) +{ + struct xfs_mru_cache_elem *mru; + struct xfs_open_zone *oz; + + mru = xfs_mru_cache_lookup(mp->m_zone_cache, ip->i_ino); + if (!mru) + return NULL; + oz = xfs_zone_cache_item(mru)->oz; + if (oz) { + /* + * GC only steals open zones at mount time, so no GC zones + * should end up in the cache. + */ + ASSERT(!oz->oz_is_gc); + ASSERT(atomic_read(&oz->oz_ref) > 0); + atomic_inc(&oz->oz_ref); + } + xfs_mru_cache_done(mp->m_zone_cache); + return oz; +} + +/* + * Update the last used zone cache for a given inode. + * + * The caller must have a reference on the open zone. + */ +static void +xfs_zone_cache_create_association( + struct xfs_inode *ip, + struct xfs_open_zone *oz) +{ + struct xfs_mount *mp = ip->i_mount; + struct xfs_zone_cache_item *item = NULL; + struct xfs_mru_cache_elem *mru; + + ASSERT(atomic_read(&oz->oz_ref) > 0); + atomic_inc(&oz->oz_ref); + + mru = xfs_mru_cache_lookup(mp->m_zone_cache, ip->i_ino); + if (mru) { + /* + * If we have an association already, update it to point to the + * new zone. + */ + item = xfs_zone_cache_item(mru); + xfs_open_zone_put(item->oz); + item->oz = oz; + xfs_mru_cache_done(mp->m_zone_cache); + return; + } + + item = kmalloc(sizeof(*item), GFP_KERNEL); + if (!item) { + xfs_open_zone_put(oz); + return; + } + item->oz = oz; + xfs_mru_cache_insert(mp->m_zone_cache, ip->i_ino, &item->mru); +} + void xfs_zone_alloc_and_submit( struct iomap_ioend *ioend, @@ -819,11 +914,16 @@ xfs_zone_alloc_and_submit( */ if (!*oz && ioend->io_offset) *oz = xfs_last_used_zone(ioend); + if (!*oz) + *oz = xfs_cached_zone(mp, ip); + if (!*oz) { select_zone: *oz = xfs_select_zone(mp, write_hint, pack_tight); if (!*oz) goto out_error; + + xfs_zone_cache_create_association(ip, *oz); } alloc_len = xfs_zone_alloc_blocks(*oz, XFS_B_TO_FSB(mp, ioend->io_size), @@ -1211,6 +1311,14 @@ xfs_mount_zones( error = xfs_zone_gc_mount(mp); if (error) goto out_free_zone_info; + + /* + * Set up a mru cache to track inode to open zone for data placement + * purposes. The magic values for group count and life time is the + * same as the defaults for file streams, which seems sane enough. + */ + xfs_mru_cache_create(&mp->m_zone_cache, mp, + 5000, 10, xfs_zone_cache_free_func); return 0; out_free_zone_info: @@ -1224,4 +1332,5 @@ xfs_unmount_zones( { xfs_zone_gc_unmount(mp); xfs_free_zone_info(mp->m_zone_info); + xfs_mru_cache_destroy(mp->m_zone_cache); } -- 2.25.1