[PATCH 21/26] xfs: make the RT allocator rtgroup aware

Darrick J. Wong
2024-08-23T00:26:39Z

From: Christoph Hellwig <hch@lst.de>

Make the allocator rtgroup aware by either picking a specific group if
there is a hint, or loop over all groups otherwise. A simple rotor is
provided to pick the placement for initial allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_bmap.c | 13 +++++-
fs/xfs/libxfs/xfs_rtbitmap.c | 6 ++-
fs/xfs/xfs_mount.h | 1
fs/xfs/xfs_rtalloc.c | 98 ++++++++++++++++++++++++++++++++++++++----
4 files changed, 105 insertions(+), 13 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 126a0d253654a..88c62e1158ac7 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3151,8 +3151,17 @@ xfs_bmap_adjacent_valid(
struct xfs_mount *mp = ap->ip->i_mount;

if (XFS_IS_REALTIME_INODE(ap->ip) &&
- (ap->datatype & XFS_ALLOC_USERDATA))
- return x < mp->m_sb.sb_rblocks;
+ (ap->datatype & XFS_ALLOC_USERDATA)) {
+ if (x >= mp->m_sb.sb_rblocks)
+ return false;
+ if (!xfs_has_rtgroups(mp))
+ return true;
+
+ return xfs_rtb_to_rgno(mp, x) == xfs_rtb_to_rgno(mp, y) &&
+ xfs_rtb_to_rgno(mp, x) < mp->m_sb.sb_rgcount &&
+ xfs_rtb_to_rtx(mp, x) < mp->m_sb.sb_rgextents;
+
+ }

return XFS_FSB_TO_AGNO(mp, x) == XFS_FSB_TO_AGNO(mp, y) &&
XFS_FSB_TO_AGNO(mp, x) < mp->m_sb.sb_agcount &&
diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
index c8958d3e0abe0..ef94b67feccd7 100644
--- a/fs/xfs/libxfs/xfs_rtbitmap.c
+++ b/fs/xfs/libxfs/xfs_rtbitmap.c
@@ -1084,11 +1084,13 @@ xfs_rtfree_extent(
* Mark more blocks free in the superblock.
*/
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, (long)len);
+
/*
* If we've now freed all the blocks, reset the file sequence
- * number to 0.
+ * number to 0 for pre-RTG file systems.
*/
- if (tp->t_frextents_delta + mp->m_sb.sb_frextents ==
+ if (!xfs_has_rtgroups(mp) &&
+ tp->t_frextents_delta + mp->m_sb.sb_frextents ==
mp->m_sb.sb_rextents) {
if (!(rbmip->i_diflags & XFS_DIFLAG_NEWRTBM))
rbmip->i_diflags |= XFS_DIFLAG_NEWRTBM;
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index c4e4f5414a299..7e68812db1be7 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -223,6 +223,7 @@ typedef struct xfs_mount {
#endif
xfs_agnumber_t m_agfrotor; /* last ag where space found */
atomic_t m_agirotor; /* last ag dir inode alloced */
+ atomic_t m_rtgrotor; /* last rtgroup rtpicked */

/* Memory shrinker to throttle and reprioritize inodegc */
struct shrinker *m_inodegc_shrinker;
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 3fedc552b51b0..2b57ff2687bf6 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1661,8 +1661,9 @@ xfs_rtalloc_align_minmax(
}

static int
-xfs_rtallocate(
+xfs_rtallocate_rtg(
struct xfs_trans *tp,
+ xfs_rgnumber_t rgno,
xfs_rtblock_t bno_hint,
xfs_rtxlen_t minlen,
xfs_rtxlen_t maxlen,
@@ -1682,16 +1683,33 @@ xfs_rtallocate(
xfs_rtxlen_t len = 0;
int error = 0;

- args.rtg = xfs_rtgroup_grab(args.mp, 0);
+ args.rtg = xfs_rtgroup_grab(args.mp, rgno);
if (!args.rtg)
return -ENOSPC;

/*
- * Lock out modifications to both the RT bitmap and summary inodes.
+ * We need to lock out modifications to both the RT bitmap and summary
+ * inodes for finding free space in xfs_rtallocate_extent_{near,size}
+ * and join the bitmap and summary inodes for the actual allocation
+ * down in xfs_rtallocate_range.
+ *
+ * For RTG-enabled file system we don't want to join the inodes to the
+ * transaction until we are committed to allocate to allocate from this
+ * RTG so that only one inode of each type is locked at a time.
+ *
+ * But for pre-RTG file systems we need to already to join the bitmap
+ * inode to the transaction for xfs_rtpick_extent, which bumps the
+ * sequence number in it, so we'll have to join the inode to the
+ * transaction early here.
+ *
+ * This is all a bit messy, but at least the mess is contained in
+ * this function.
*/
if (!*rtlocked) {
xfs_rtgroup_lock(args.rtg, XFS_RTGLOCK_BITMAP);
- xfs_rtgroup_trans_join(tp, args.rtg, XFS_RTGLOCK_BITMAP);
+ if (!xfs_has_rtgroups(args.mp))
+ xfs_rtgroup_trans_join(tp, args.rtg,
+ XFS_RTGLOCK_BITMAP);
*rtlocked = true;
}

@@ -1701,7 +1719,7 @@ xfs_rtallocate(
*/
if (bno_hint)
start = xfs_rtb_to_rtx(args.mp, bno_hint);
- else if (initial_user_data)
+ else if (!xfs_has_rtgroups(args.mp) && initial_user_data)
start = xfs_rtpick_extent(args.rtg, tp, maxlen);

if (start) {
@@ -1722,8 +1740,16 @@ xfs_rtallocate(
prod, &rtx);
}

- if (error)
+ if (error) {
+ if (xfs_has_rtgroups(args.mp)) {
+ xfs_rtgroup_unlock(args.rtg, XFS_RTGLOCK_BITMAP);
+ *rtlocked = false;
+ }
goto out_release;
+ }
+
+ if (xfs_has_rtgroups(args.mp))
+ xfs_rtgroup_trans_join(tp, args.rtg, XFS_RTGLOCK_BITMAP);

error = xfs_rtallocate_range(&args, rtx, len);
if (error)
@@ -1741,6 +1767,53 @@ xfs_rtallocate(
return error;
}

+static int
+xfs_rtallocate_rtgs(
+ struct xfs_trans *tp,
+ xfs_fsblock_t bno_hint,
+ xfs_rtxlen_t minlen,
+ xfs_rtxlen_t maxlen,
+ xfs_rtxlen_t prod,
+ bool wasdel,
+ bool initial_user_data,
+ xfs_rtblock_t *bno,
+ xfs_extlen_t *blen)
+{
+ struct xfs_mount *mp = tp->t_mountp;
+ xfs_rgnumber_t start_rgno, rgno;
+ int error;
+
+ /*
+ * For now this just blindly iterates over the RTGs for an initial
+ * allocation. We could try to keep an in-memory rtg_longest member
+ * to avoid the locking when just looking for big enough free space,
+ * but for now this keep things simple.
+ */
+ if (bno_hint != NULLFSBLOCK)
+ start_rgno = xfs_rtb_to_rgno(mp, bno_hint);
+ else
+ start_rgno = (atomic_inc_return(&mp->m_rtgrotor) - 1) %
+ mp->m_sb.sb_rgcount;
+
+ rgno = start_rgno;
+ do {
+ bool rtlocked = false;
+
+ error = xfs_rtallocate_rtg(tp, rgno, bno_hint, minlen, maxlen,
+ prod, wasdel, initial_user_data, &rtlocked,
+ bno, blen);
+ if (error != -ENOSPC)
+ return error;
+ ASSERT(!rtlocked);
+
+ if (++rgno == mp->m_sb.sb_rgcount)
+ rgno = 0;
+ bno_hint = NULLFSBLOCK;
+ } while (rgno != start_rgno);
+
+ return -ENOSPC;
+}
+
static int
xfs_rtallocate_align(
struct xfs_bmalloca *ap,
@@ -1835,9 +1908,16 @@ xfs_bmap_rtalloc(
if (xfs_bmap_adjacent(ap))
bno_hint = ap->blkno;

- error = xfs_rtallocate(ap->tp, bno_hint, raminlen, ralen, prod,
- ap->wasdel, initial_user_data, &rtlocked,
- &ap->blkno, &ap->length);
+ if (xfs_has_rtgroups(ap->ip->i_mount)) {
+ error = xfs_rtallocate_rtgs(ap->tp, bno_hint, raminlen, ralen,
+ prod, ap->wasdel, initial_user_data,
+ &ap->blkno, &ap->length);
+ } else {
+ error = xfs_rtallocate_rtg(ap->tp, 0, bno_hint, raminlen, ralen,
+ prod, ap->wasdel, initial_user_data,
+ &rtlocked, &ap->blkno, &ap->length);
+ }
+
if (error == -ENOSPC) {
if (!noalign) {
/*