Re: [PATCH 09/43] xfs: generalize the freespace and reserved blocks handling

Darrick J. Wong
2024-12-12T21:37:19Z

On Wed, Dec 11, 2024 at 09:54:34AM +0100, Christoph Hellwig wrote:
> The main handling of the incore per-cpu freespace counters is already
> handled in xfs_mod_freecounter for both the block and RT extent cases,
> but the actual counter is passed in an special cases.
>
> Replace both the percpu counters and the resblks counters with arrays,
> so that support reserved RT extents can be supported, which will be
> needed for garbarge collection on zoned devices.
>
> Use helpers to access the freespace counters everywhere intead of
> poking through the abstraction by using the percpu_count helpers
> directly. This also switches the flooring of the frextents counter
> to 0 in statfs for the rthinherit case to a manual min_t call to match
> the handling of the fdblocks counter for normal file systems.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/libxfs/xfs_ialloc.c | 2 +-
> fs/xfs/libxfs/xfs_metafile.c | 2 +-
> fs/xfs/libxfs/xfs_sb.c | 7 +--
> fs/xfs/scrub/fscounters.c | 13 +++---
> fs/xfs/scrub/fscounters_repair.c | 4 +-
> fs/xfs/scrub/newbt.c | 2 +-
> fs/xfs/xfs_fsops.c | 27 ++++++------
> fs/xfs/xfs_fsops.h | 3 +-
> fs/xfs/xfs_icache.c | 4 +-
> fs/xfs/xfs_ioctl.c | 12 +++---
> fs/xfs/xfs_iomap.c | 9 ++--
> fs/xfs/xfs_mount.c | 58 ++++++++++++++++---------
> fs/xfs/xfs_mount.h | 65 +++++++++++++++++++---------
> fs/xfs/xfs_rtalloc.c | 2 +-
> fs/xfs/xfs_super.c | 74 ++++++++++++++++++--------------
> fs/xfs/xfs_trace.h | 2 +-
> 16 files changed, 171 insertions(+), 115 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> index f3a840a425f5..57513ba19d6a 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.c
> +++ b/fs/xfs/libxfs/xfs_ialloc.c
> @@ -1927,7 +1927,7 @@ xfs_dialloc(
> * that we can immediately allocate, but then we allow allocation on the
> * second pass if we fail to find an AG with free inodes in it.
> */
> - if (percpu_counter_read_positive(&mp->m_fdblocks) <
> + if (xfs_estimate_freecounter(mp, XC_FREE_BLOCKS) <
> mp->m_low_space[XFS_LOWSP_1_PCNT]) {
> ok_alloc = false;
> low_space = true;
> diff --git a/fs/xfs/libxfs/xfs_metafile.c b/fs/xfs/libxfs/xfs_metafile.c
> index e151663cc9ef..c84820f5bdc6 100644
> --- a/fs/xfs/libxfs/xfs_metafile.c
> +++ b/fs/xfs/libxfs/xfs_metafile.c
> @@ -77,7 +77,7 @@ xfs_metafile_resv_can_cover(
> * There aren't enough blocks left in the inode's reservation, but it
> * isn't critical unless there also isn't enough free space.
> */
> - return __percpu_counter_compare(&ip->i_mount->m_fdblocks,
> + return xfs_compare_freecounter(ip->i_mount, XC_FREE_BLOCKS,
> rhs - ip->i_delayed_blks, 2048) >= 0;
> }
>
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index 3dc5f5dba162..090f133f4da3 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -1266,7 +1266,7 @@ xfs_log_sb(
> percpu_counter_sum_positive(&mp->m_ifree),
> mp->m_sb.sb_icount);
> mp->m_sb.sb_fdblocks =
> - percpu_counter_sum_positive(&mp->m_fdblocks);
> + max(0LL, xfs_sum_freecounter(mp, XC_FREE_BLOCKS));
> }
>
> /*
> @@ -1275,9 +1275,10 @@ xfs_log_sb(
> * we handle nearly-lockless reservations, so we must use the _positive
> * variant here to avoid writing out nonsense frextents.
> */
> - if (xfs_has_rtgroups(mp))
> + if (xfs_has_rtgroups(mp)) {
> mp->m_sb.sb_frextents =
> - percpu_counter_sum_positive(&mp->m_frextents);
> + xfs_sum_freecounter(mp, XC_FREE_RTEXTENTS);

Curious. xfs_sum_freecounter returns percpu_counter_sum, not its
_positive variant. This seems like a bug? Or at least an omitted
max(0LL, ...) call?

> + }
>
> xfs_sb_to_disk(bp->b_addr, &mp->m_sb);
> xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SB_BUF);
> diff --git a/fs/xfs/scrub/fscounters.c b/fs/xfs/scrub/fscounters.c
> index ca23cf4db6c5..732658a62a2d 100644
> --- a/fs/xfs/scrub/fscounters.c
> +++ b/fs/xfs/scrub/fscounters.c
> @@ -350,7 +350,7 @@ xchk_fscount_aggregate_agcounts(
> * The global incore space reservation is taken from the incore
> * counters, so leave that out of the computation.
> */
> - fsc->fdblocks -= mp->m_resblks_avail;
> + fsc->fdblocks -= mp->m_resblks[XC_FREE_BLOCKS].avail;
>
> /*
> * Delayed allocation reservations are taken out of the incore counters
> @@ -513,8 +513,8 @@ xchk_fscounters(
> /* Snapshot the percpu counters. */
> icount = percpu_counter_sum(&mp->m_icount);
> ifree = percpu_counter_sum(&mp->m_ifree);
> - fdblocks = percpu_counter_sum(&mp->m_fdblocks);
> - frextents = percpu_counter_sum(&mp->m_frextents);
> + fdblocks = xfs_sum_freecounter(mp, XC_FREE_BLOCKS);
> + frextents = xfs_sum_freecounter(mp, XC_FREE_RTEXTENTS);
>
> /* No negative values, please! */
> if (icount < 0 || ifree < 0)
> @@ -589,15 +589,16 @@ xchk_fscounters(
> try_again = true;
> }
>
> - if (!xchk_fscount_within_range(sc, fdblocks, &mp->m_fdblocks,
> - fsc->fdblocks)) {
> + if (!xchk_fscount_within_range(sc, fdblocks,
> + &mp->m_free[XC_FREE_BLOCKS], fsc->fdblocks)) {
> if (fsc->frozen)
> xchk_set_corrupt(sc);
> else
> try_again = true;
> }
>
> - if (!xchk_fscount_within_range(sc, frextents, &mp->m_frextents,
> + if (!xchk_fscount_within_range(sc, frextents,
> + &mp->m_free[XC_FREE_RTEXTENTS],
> fsc->frextents - fsc->frextents_delayed)) {
> if (fsc->frozen)
> xchk_set_corrupt(sc);
> diff --git a/fs/xfs/scrub/fscounters_repair.c b/fs/xfs/scrub/fscounters_repair.c
> index cda13447a373..8fb0db78489e 100644
> --- a/fs/xfs/scrub/fscounters_repair.c
> +++ b/fs/xfs/scrub/fscounters_repair.c
> @@ -64,7 +64,7 @@ xrep_fscounters(
>
> percpu_counter_set(&mp->m_icount, fsc->icount);
> percpu_counter_set(&mp->m_ifree, fsc->ifree);
> - percpu_counter_set(&mp->m_fdblocks, fsc->fdblocks);
> + xfs_set_freecounter(mp, XC_FREE_BLOCKS, fsc->fdblocks);
>
> /*
> * Online repair is only supported on v5 file systems, which require
> @@ -74,7 +74,7 @@ xrep_fscounters(
> * track of the delalloc reservations separately, as they are are
> * subtracted from m_frextents, but not included in sb_frextents.
> */
> - percpu_counter_set(&mp->m_frextents,
> + xfs_set_freecounter(mp, XC_FREE_RTEXTENTS,
> fsc->frextents - fsc->frextents_delayed);
> if (!xfs_has_rtgroups(mp))
> mp->m_sb.sb_frextents = fsc->frextents;
> diff --git a/fs/xfs/scrub/newbt.c b/fs/xfs/scrub/newbt.c
> index ac38f5843090..3e46b04f427f 100644
> --- a/fs/xfs/scrub/newbt.c
> +++ b/fs/xfs/scrub/newbt.c
> @@ -62,7 +62,7 @@ xrep_newbt_estimate_slack(
> free = sc->sa.pag->pagf_freeblks;
> sz = xfs_ag_block_count(sc->mp, pag_agno(sc->sa.pag));
> } else {
> - free = percpu_counter_sum(&sc->mp->m_fdblocks);
> + free = xfs_sum_freecounter(sc->mp, XC_FREE_BLOCKS);
> sz = sc->mp->m_sb.sb_dblocks;
> }
>
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 455298503d01..bb2e31e338b8 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -366,6 +366,7 @@ xfs_growfs_log(
> int
> xfs_reserve_blocks(
> struct xfs_mount *mp,
> + enum xfs_free_counter ctr,
> uint64_t request)
> {
> int64_t lcounter, delta;
> @@ -373,6 +374,8 @@ xfs_reserve_blocks(
> int64_t free;
> int error = 0;
>
> + ASSERT(ctr < XC_FREE_NR);
> +
> /*
> * With per-cpu counters, this becomes an interesting problem. we need
> * to work out if we are freeing or allocation blocks first, then we can
> @@ -391,16 +394,16 @@ xfs_reserve_blocks(
> * counters directly since we shouldn't have any problems unreserving
> * space.
> */
> - if (mp->m_resblks > request) {
> - lcounter = mp->m_resblks_avail - request;
> + if (mp->m_resblks[ctr].total > request) {
> + lcounter = mp->m_resblks[ctr].avail - request;
> if (lcounter > 0) { /* release unused blocks */
> fdblks_delta = lcounter;
> - mp->m_resblks_avail -= lcounter;
> + mp->m_resblks[ctr].avail -= lcounter;
> }
> - mp->m_resblks = request;
> + mp->m_resblks[ctr].total = request;
> if (fdblks_delta) {
> spin_unlock(&mp->m_sb_lock);
> - xfs_add_fdblocks(mp, fdblks_delta);
> + xfs_add_freecounter(mp, ctr, fdblks_delta);
> spin_lock(&mp->m_sb_lock);
> }
>
> @@ -409,7 +412,7 @@ xfs_reserve_blocks(
>
> /*
> * If the request is larger than the current reservation, reserve the
> - * blocks before we update the reserve counters. Sample m_fdblocks and
> + * blocks before we update the reserve counters. Sample m_free and
> * perform a partial reservation if the request exceeds free space.
> *
> * The code below estimates how many blocks it can request from
> @@ -419,10 +422,10 @@ xfs_reserve_blocks(
> * space to fill it because mod_fdblocks will refill an undersized
> * reserve when it can.
> */
> - free = percpu_counter_sum(&mp->m_fdblocks) -
> - xfs_fdblocks_unavailable(mp);
> - delta = request - mp->m_resblks;
> - mp->m_resblks = request;
> + free = xfs_sum_freecounter(mp, ctr) -
> + xfs_freecounter_unavailable(mp, ctr);
> + delta = request - mp->m_resblks[ctr].total;
> + mp->m_resblks[ctr].total = request;
> if (delta > 0 && free > 0) {
> /*
> * We'll either succeed in getting space from the free block
> @@ -436,9 +439,9 @@ xfs_reserve_blocks(
> */
> fdblks_delta = min(free, delta);
> spin_unlock(&mp->m_sb_lock);
> - error = xfs_dec_fdblocks(mp, fdblks_delta, 0);
> + error = xfs_dec_freecounter(mp, ctr, fdblks_delta, 0);
> if (!error)
> - xfs_add_fdblocks(mp, fdblks_delta);
> + xfs_add_freecounter(mp, ctr, fdblks_delta);
> spin_lock(&mp->m_sb_lock);
> }
> out:
> diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
> index 3e2f73bcf831..9d23c361ef56 100644
> --- a/fs/xfs/xfs_fsops.h
> +++ b/fs/xfs/xfs_fsops.h
> @@ -8,7 +8,8 @@
>
> int xfs_growfs_data(struct xfs_mount *mp, struct xfs_growfs_data *in);
> int xfs_growfs_log(struct xfs_mount *mp, struct xfs_growfs_log *in);
> -int xfs_reserve_blocks(struct xfs_mount *mp, uint64_t request);
> +int xfs_reserve_blocks(struct xfs_mount *mp, enum xfs_free_counter cnt,
> + uint64_t request);
> int xfs_fs_goingdown(struct xfs_mount *mp, uint32_t inflags);
>
> int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 7b6c026d01a1..c9ded501e89b 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -2076,7 +2076,7 @@ xfs_inodegc_want_queue_rt_file(
> if (!XFS_IS_REALTIME_INODE(ip))
> return false;
>
> - if (__percpu_counter_compare(&mp->m_frextents,
> + if (xfs_compare_freecounter(mp, XC_FREE_RTEXTENTS,
> mp->m_low_rtexts[XFS_LOWSP_5_PCNT],
> XFS_FDBLOCKS_BATCH) < 0)
> return true;
> @@ -2104,7 +2104,7 @@ xfs_inodegc_want_queue_work(
> if (items > mp->m_ino_geo.inodes_per_cluster)
> return true;
>
> - if (__percpu_counter_compare(&mp->m_fdblocks,
> + if (xfs_compare_freecounter(mp, XC_FREE_BLOCKS,
> mp->m_low_space[XFS_LOWSP_5_PCNT],
> XFS_FDBLOCKS_BATCH) < 0)
> return true;
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index de8ba5345e17..d3cf62d81f0d 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1131,15 +1131,15 @@ xfs_ioctl_getset_resblocks(
> error = mnt_want_write_file(filp);
> if (error)
> return error;
> - error = xfs_reserve_blocks(mp, fsop.resblks);
> + error = xfs_reserve_blocks(mp, XC_FREE_BLOCKS, fsop.resblks);
> mnt_drop_write_file(filp);
> if (error)
> return error;
> }
>
> spin_lock(&mp->m_sb_lock);
> - fsop.resblks = mp->m_resblks;
> - fsop.resblks_avail = mp->m_resblks_avail;
> + fsop.resblks = mp->m_resblks[XC_FREE_BLOCKS].total;
> + fsop.resblks_avail = mp->m_resblks[XC_FREE_BLOCKS].avail;
> spin_unlock(&mp->m_sb_lock);
>
> if (copy_to_user(arg, &fsop, sizeof(fsop)))
> @@ -1155,9 +1155,9 @@ xfs_ioctl_fs_counts(
> struct xfs_fsop_counts out = {
> .allocino = percpu_counter_read_positive(&mp->m_icount),
> .freeino = percpu_counter_read_positive(&mp->m_ifree),
> - .freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
> - xfs_fdblocks_unavailable(mp),
> - .freertx = percpu_counter_read_positive(&mp->m_frextents),
> + .freedata = xfs_estimate_freecounter(mp, XC_FREE_BLOCKS) -
> + xfs_freecounter_unavailable(mp, XC_FREE_BLOCKS),
> + .freertx = xfs_estimate_freecounter(mp, XC_FREE_RTEXTENTS),
> };
>
> if (copy_to_user(uarg, &out, sizeof(out)))
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index b3783d7b8ebe..f3f4b5c328c3 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -432,13 +432,14 @@ xfs_quota_calc_throttle(
>
> static int64_t
> xfs_iomap_freesp(
> - struct percpu_counter *counter,
> + struct xfs_mount *mp,
> + unsigned int idx,
> uint64_t low_space[XFS_LOWSP_MAX],
> int *shift)
> {
> int64_t freesp;
>
> - freesp = percpu_counter_read_positive(counter);
> + freesp = xfs_estimate_freecounter(mp, idx);
> if (freesp < low_space[XFS_LOWSP_5_PCNT]) {
> *shift = 2;
> if (freesp < low_space[XFS_LOWSP_4_PCNT])
> @@ -537,10 +538,10 @@ xfs_iomap_prealloc_size(
>
> if (unlikely(XFS_IS_REALTIME_INODE(ip)))
> freesp = xfs_rtbxlen_to_blen(mp,
> - xfs_iomap_freesp(&mp->m_frextents,
> + xfs_iomap_freesp(mp, XC_FREE_RTEXTENTS,
> mp->m_low_rtexts, &shift));
> else
> - freesp = xfs_iomap_freesp(&mp->m_fdblocks, mp->m_low_space,
> + freesp = xfs_iomap_freesp(mp, XC_FREE_BLOCKS, mp->m_low_space,
> &shift);
>
> /*
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index 66b91b582691..4174035b2ac9 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -1058,7 +1058,8 @@ xfs_mountfs(
> * we were already there on the last unmount. Warn if this occurs.
> */
> if (!xfs_is_readonly(mp)) {
> - error = xfs_reserve_blocks(mp, xfs_default_resblks(mp));
> + error = xfs_reserve_blocks(mp, XC_FREE_BLOCKS,
> + xfs_default_resblks(mp));
> if (error)
> xfs_warn(mp,
> "Unable to allocate reserve blocks. Continuing without reserve pool.");
> @@ -1178,7 +1179,7 @@ xfs_unmountfs(
> * we only every apply deltas to the superblock and hence the incore
> * value does not matter....
> */
> - error = xfs_reserve_blocks(mp, 0);
> + error = xfs_reserve_blocks(mp, XC_FREE_BLOCKS, 0);
> if (error)
> xfs_warn(mp, "Unable to free reserved block pool. "
> "Freespace may not be correct on next mount.");
> @@ -1225,52 +1226,68 @@ xfs_fs_writable(
> return true;
> }
>
> +/*
> + * Estimate the amount of free space that is not available to userspace and is
> + * not explicitly reserved from the incore fdblocks. This includes:
> + *
> + * - The minimum number of blocks needed to support splitting a bmap btree
> + * - The blocks currently in use by the freespace btrees because they record
> + * the actual blocks that will fill per-AG metadata space reservations
> + */
> +uint64_t
> +xfs_freecounter_unavailable(
> + struct xfs_mount *mp,
> + enum xfs_free_counter ctr)
> +{
> + if (ctr == XC_FREE_RTEXTENTS)
> + return 0;
> + return mp->m_alloc_set_aside + atomic64_read(&mp->m_allocbt_blks);
> +}
> +
> void
> xfs_add_freecounter(
> struct xfs_mount *mp,
> - struct percpu_counter *counter,
> + enum xfs_free_counter ctr,
> uint64_t delta)
> {
> - bool has_resv_pool = (counter == &mp->m_fdblocks);
> uint64_t res_used;
>
> /*
> * If the reserve pool is depleted, put blocks back into it first.
> * Most of the time the pool is full.
> */
> - if (!has_resv_pool || mp->m_resblks == mp->m_resblks_avail) {
> - percpu_counter_add(counter, delta);
> + if (likely(mp->m_resblks[ctr].total == mp->m_resblks[ctr].avail)) {
> + percpu_counter_add(&mp->m_free[ctr], delta);
> return;
> }
>
> spin_lock(&mp->m_sb_lock);
> - res_used = mp->m_resblks - mp->m_resblks_avail;
> + res_used = mp->m_resblks[ctr].total - mp->m_resblks[ctr].avail;
> if (res_used > delta) {
> - mp->m_resblks_avail += delta;
> + mp->m_resblks[ctr].avail += delta;
> } else {
> delta -= res_used;
> - mp->m_resblks_avail = mp->m_resblks;
> - percpu_counter_add(counter, delta);
> + mp->m_resblks[ctr].avail = mp->m_resblks[ctr].total;
> + percpu_counter_add(&mp->m_free[ctr], delta);
> }
> spin_unlock(&mp->m_sb_lock);
> }
>
> +
> +/* Adjust in-core free blocks or RT extents. */
> int
> xfs_dec_freecounter(
> struct xfs_mount *mp,
> - struct percpu_counter *counter,
> + enum xfs_free_counter ctr,
> uint64_t delta,
> bool rsvd)
> {
> + struct percpu_counter *counter = &mp->m_free[ctr];
> int64_t lcounter;
> uint64_t set_aside = 0;
> s32 batch;
> - bool has_resv_pool;
>
> - ASSERT(counter == &mp->m_fdblocks || counter == &mp->m_frextents);
> - has_resv_pool = (counter == &mp->m_fdblocks);
> - if (rsvd)
> - ASSERT(has_resv_pool);
> + ASSERT(ctr < XC_FREE_NR);
>
> /*
> * Taking blocks away, need to be more accurate the closer we
> @@ -1297,8 +1314,7 @@ xfs_dec_freecounter(
> * problems (i.e. transaction abort, pagecache discards, etc.) than
> * slightly premature -ENOSPC.
> */
> - if (has_resv_pool)
> - set_aside = xfs_fdblocks_unavailable(mp);
> + set_aside = xfs_freecounter_unavailable(mp, ctr);

Nit: I think you can get rid of the set_aside = 0; above?

> percpu_counter_add_batch(counter, -((int64_t)delta), batch);
> if (__percpu_counter_compare(counter, set_aside,
> XFS_FDBLOCKS_BATCH) >= 0) {
> @@ -1312,12 +1328,12 @@ xfs_dec_freecounter(
> */
> spin_lock(&mp->m_sb_lock);
> percpu_counter_add(counter, delta);
> - if (!has_resv_pool || !rsvd)
> + if (!rsvd)
> goto fdblocks_enospc;
>
> - lcounter = (long long)mp->m_resblks_avail - delta;
> + lcounter = (long long)mp->m_resblks[ctr].avail - delta;
> if (lcounter >= 0) {
> - mp->m_resblks_avail = lcounter;
> + mp->m_resblks[ctr].avail = lcounter;
> spin_unlock(&mp->m_sb_lock);
> return 0;
> }
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index fbed172d6770..d92bce7bc184 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -105,6 +105,12 @@ struct xfs_groups {
> uint64_t blkmask;
> };
>
> +enum xfs_free_counter {
> + XC_FREE_BLOCKS, /* free block counter */
> + XC_FREE_RTEXTENTS, /* free rt extent counter */
> + XC_FREE_NR,
> +};
> +
> /*
> * The struct xfsmount layout is optimised to separate read-mostly variables
> * from variables that are frequently modified. We put the read-mostly variables
> @@ -222,8 +228,7 @@ typedef struct xfs_mount {
> spinlock_t ____cacheline_aligned m_sb_lock; /* sb counter lock */
> struct percpu_counter m_icount; /* allocated inodes counter */
> struct percpu_counter m_ifree; /* free inodes counter */
> - struct percpu_counter m_fdblocks; /* free block counter */
> - struct percpu_counter m_frextents; /* free rt extent counter */
> + struct percpu_counter m_free[XC_FREE_NR];
>
> /*
> * Count of data device blocks reserved for delayed allocations,
> @@ -245,9 +250,11 @@ typedef struct xfs_mount {
> atomic64_t m_allocbt_blks;
>
> struct xfs_groups m_groups[XG_TYPE_MAX];
> - uint64_t m_resblks; /* total reserved blocks */
> - uint64_t m_resblks_avail;/* available reserved blocks */
> - uint64_t m_resblks_save; /* reserved blks @ remount,ro */
> + struct {
> + uint64_t total; /* total reserved blocks */
> + uint64_t avail; /* available reserved blocks */
> + uint64_t save; /* reserved blks @ remount,ro */
> + } m_resblks[XC_FREE_NR];
> struct delayed_work m_reclaim_work; /* background inode reclaim */
> struct dentry *m_debugfs; /* debugfs parent */
> struct xfs_kobj m_kobj;
> @@ -646,45 +653,61 @@ extern void xfs_unmountfs(xfs_mount_t *);
> */
> #define XFS_FDBLOCKS_BATCH 1024
>
> +uint64_t xfs_freecounter_unavailable(struct xfs_mount *mp,
> + enum xfs_free_counter ctr);
> +
> +static inline s64 xfs_sum_freecounter(struct xfs_mount *mp,
> + enum xfs_free_counter ctr)
> +{
> + return percpu_counter_sum(&mp->m_free[ctr]);
> +}
> +
> /*
> - * Estimate the amount of free space that is not available to userspace and is
> - * not explicitly reserved from the incore fdblocks. This includes:
> - *
> - * - The minimum number of blocks needed to support splitting a bmap btree
> - * - The blocks currently in use by the freespace btrees because they record
> - * the actual blocks that will fill per-AG metadata space reservations
> + * This just provides and estimate without the cpu-local updates, use
> + * xfs_sum_freecounter for the exact value.
> */
> -static inline uint64_t
> -xfs_fdblocks_unavailable(
> - struct xfs_mount *mp)
> +static inline s64 xfs_estimate_freecounter(struct xfs_mount *mp,
> + enum xfs_free_counter ctr)
> +{
> + return percpu_counter_read_positive(&mp->m_free[ctr]);
> +}
> +
> +static inline int xfs_compare_freecounter(struct xfs_mount *mp,
> + enum xfs_free_counter ctr, s64 rhs, s32 batch)
> +{
> + return __percpu_counter_compare(&mp->m_free[ctr], rhs, batch);
> +}
> +
> +static inline void xfs_set_freecounter(struct xfs_mount *mp,
> + enum xfs_free_counter ctr, uint64_t val)
> {
> - return mp->m_alloc_set_aside + atomic64_read(&mp->m_allocbt_blks);
> + percpu_counter_set(&mp->m_free[ctr], val);
> }
>
> -int xfs_dec_freecounter(struct xfs_mount *mp, struct percpu_counter *counter,
> +int xfs_dec_freecounter(struct xfs_mount *mp, enum xfs_free_counter ctr,
> uint64_t delta, bool rsvd);
> -void xfs_add_freecounter(struct xfs_mount *mp, struct percpu_counter *counter,
> +void xfs_add_freecounter(struct xfs_mount *mp, enum xfs_free_counter ctr,
> uint64_t delta);
>
> static inline int xfs_dec_fdblocks(struct xfs_mount *mp, uint64_t delta,
> bool reserved)
> {
> - return xfs_dec_freecounter(mp, &mp->m_fdblocks, delta, reserved);
> + return xfs_dec_freecounter(mp, XC_FREE_BLOCKS, delta, reserved);
> }
>
> static inline void xfs_add_fdblocks(struct xfs_mount *mp, uint64_t delta)
> {
> - xfs_add_freecounter(mp, &mp->m_fdblocks, delta);
> + xfs_add_freecounter(mp, XC_FREE_BLOCKS, delta);
> }
>
> static inline int xfs_dec_frextents(struct xfs_mount *mp, uint64_t delta)
> {
> - return xfs_dec_freecounter(mp, &mp->m_frextents, delta, false);
> + return xfs_dec_freecounter(mp, XC_FREE_RTEXTENTS, delta, false);
> }
>
> static inline void xfs_add_frextents(struct xfs_mount *mp, uint64_t delta)
> {
> - xfs_add_freecounter(mp, &mp->m_frextents, delta);
> + xfs_add_freecounter(mp, XC_FREE_RTEXTENTS, delta);
> }
>
> extern int xfs_readsb(xfs_mount_t *, int);
> diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
> index bc18b694db75..8da2498417f5 100644
> --- a/fs/xfs/xfs_rtalloc.c
> +++ b/fs/xfs/xfs_rtalloc.c
> @@ -1519,7 +1519,7 @@ xfs_rtalloc_reinit_frextents(
> spin_lock(&mp->m_sb_lock);
> mp->m_sb.sb_frextents = val;
> spin_unlock(&mp->m_sb_lock);
> - percpu_counter_set(&mp->m_frextents, mp->m_sb.sb_frextents);
> + xfs_set_freecounter(mp, XC_FREE_RTEXTENTS, mp->m_sb.sb_frextents);
> return 0;
> }
>
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index a74a0cc1f6f6..1960ee0aad45 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -834,10 +834,11 @@ xfs_statfs_data(
> struct kstatfs *st)
> {
> int64_t fdblocks =
> - percpu_counter_sum(&mp->m_fdblocks);
> + xfs_sum_freecounter(mp, XC_FREE_BLOCKS);
>
> /* make sure st->f_bfree does not underflow */
> - st->f_bfree = max(0LL, fdblocks - xfs_fdblocks_unavailable(mp));
> + st->f_bfree = max(0LL,
> + fdblocks - xfs_freecounter_unavailable(mp, XC_FREE_BLOCKS));
> st->f_blocks = mp->m_sb.sb_dblocks - xfs_internal_log_size(mp);
> }
>
> @@ -852,9 +853,9 @@ xfs_statfs_rt(
> struct kstatfs *st)
> {
> int64_t freertx =
> - percpu_counter_sum_positive(&mp->m_frextents);
> + xfs_sum_freecounter(mp, XC_FREE_RTEXTENTS);

Same question as I had for xfs_log_sb() about _positive.

--D

>
> - st->f_bfree = xfs_rtbxlen_to_blen(mp, freertx);
> + st->f_bfree = xfs_rtbxlen_to_blen(mp, max(0LL, freertx));
> st->f_blocks = mp->m_sb.sb_rblocks;
> }
>
> @@ -920,24 +921,32 @@ xfs_fs_statfs(
> }
>
> STATIC void
> -xfs_save_resvblks(struct xfs_mount *mp)
> +xfs_save_resvblks(
> + struct xfs_mount *mp)
> {
> - mp->m_resblks_save = mp->m_resblks;
> - xfs_reserve_blocks(mp, 0);
> + enum xfs_free_counter i;
> +
> + for (i = 0; i < XC_FREE_NR; i++) {
> + mp->m_resblks[i].save = mp->m_resblks[i].total;
> + xfs_reserve_blocks(mp, i, 0);
> + }
> }
>
> STATIC void
> -xfs_restore_resvblks(struct xfs_mount *mp)
> +xfs_restore_resvblks(
> + struct xfs_mount *mp)
> {
> - uint64_t resblks;
> + uint64_t resblks;
> + enum xfs_free_counter i;
>
> - if (mp->m_resblks_save) {
> - resblks = mp->m_resblks_save;
> - mp->m_resblks_save = 0;
> - } else
> - resblks = xfs_default_resblks(mp);
> -
> - xfs_reserve_blocks(mp, resblks);
> + for (i = 0; i < XC_FREE_NR; i++) {
> + if (mp->m_resblks[i].save) {
> + resblks = mp->m_resblks[i].save;
> + mp->m_resblks[i].save = 0;
> + } else
> + resblks = xfs_default_resblks(mp);
> + xfs_reserve_blocks(mp, i, resblks);
> + }
> }
>
> /*
> @@ -1063,7 +1072,8 @@ static int
> xfs_init_percpu_counters(
> struct xfs_mount *mp)
> {
> - int error;
> + int error;
> + enum xfs_free_counter i;
>
> error = percpu_counter_init(&mp->m_icount, 0, GFP_KERNEL);
> if (error)
> @@ -1073,30 +1083,28 @@ xfs_init_percpu_counters(
> if (error)
> goto free_icount;
>
> - error = percpu_counter_init(&mp->m_fdblocks, 0, GFP_KERNEL);
> - if (error)
> - goto free_ifree;
> -
> error = percpu_counter_init(&mp->m_delalloc_blks, 0, GFP_KERNEL);
> if (error)
> - goto free_fdblocks;
> + goto free_ifree;
>
> error = percpu_counter_init(&mp->m_delalloc_rtextents, 0, GFP_KERNEL);
> if (error)
> goto free_delalloc;
>
> - error = percpu_counter_init(&mp->m_frextents, 0, GFP_KERNEL);
> - if (error)
> - goto free_delalloc_rt;
> + for (i = 0; i < XC_FREE_NR; i++) {
> + error = percpu_counter_init(&mp->m_free[i], 0, GFP_KERNEL);
> + if (error)
> + goto free_freecounters;
> + }
>
> return 0;
>
> -free_delalloc_rt:
> +free_freecounters:
> + while (--i > 0)
> + percpu_counter_destroy(&mp->m_free[i]);
> percpu_counter_destroy(&mp->m_delalloc_rtextents);
> free_delalloc:
> percpu_counter_destroy(&mp->m_delalloc_blks);
> -free_fdblocks:
> - percpu_counter_destroy(&mp->m_fdblocks);
> free_ifree:
> percpu_counter_destroy(&mp->m_ifree);
> free_icount:
> @@ -1110,24 +1118,26 @@ xfs_reinit_percpu_counters(
> {
> percpu_counter_set(&mp->m_icount, mp->m_sb.sb_icount);
> percpu_counter_set(&mp->m_ifree, mp->m_sb.sb_ifree);
> - percpu_counter_set(&mp->m_fdblocks, mp->m_sb.sb_fdblocks);
> - percpu_counter_set(&mp->m_frextents, mp->m_sb.sb_frextents);
> + xfs_set_freecounter(mp, XC_FREE_BLOCKS, mp->m_sb.sb_fdblocks);
> + xfs_set_freecounter(mp, XC_FREE_RTEXTENTS, mp->m_sb.sb_frextents);
> }
>
> static void
> xfs_destroy_percpu_counters(
> struct xfs_mount *mp)
> {
> + enum xfs_free_counter i;
> +
> + for (i = 0; i < XC_FREE_NR; i++)
> + percpu_counter_destroy(&mp->m_free[i]);
> percpu_counter_destroy(&mp->m_icount);
> percpu_counter_destroy(&mp->m_ifree);
> - percpu_counter_destroy(&mp->m_fdblocks);
> ASSERT(xfs_is_shutdown(mp) ||
> percpu_counter_sum(&mp->m_delalloc_rtextents) == 0);
> percpu_counter_destroy(&mp->m_delalloc_rtextents);
> ASSERT(xfs_is_shutdown(mp) ||
> percpu_counter_sum(&mp->m_delalloc_blks) == 0);
> percpu_counter_destroy(&mp->m_delalloc_blks);
> - percpu_counter_destroy(&mp->m_frextents);
> }
>
> static int
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 4fe689410eb6..15dec76fec10 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -5621,7 +5621,7 @@ DECLARE_EVENT_CLASS(xfs_metafile_resv_class,
>
> __entry->dev = mp->m_super->s_dev;
> __entry->ino = ip->i_ino;
> - __entry->freeblks = percpu_counter_sum(&mp->m_fdblocks);
> + __entry->freeblks = xfs_sum_freecounter(mp, XC_FREE_BLOCKS);
> __entry->reserved = ip->i_delayed_blks;
> __entry->asked = ip->i_meta_resv_asked;
> __entry->used = ip->i_nblocks;
> --
> 2.45.2
>
>