[PATCH 43/43] xfs: export zone stats in /proc/*/mountstats

Christoph Hellwig
2024-12-11T08:58:41Z

From: Hans Holmberg <hans.holmberg@wdc.com>

Add the per-zone life time hint and the used block distribution
for fully written zones, grouping reclaimable zones in fixed-percentage
buckets spanning 0..9%, 10..19% and full zones as 100% used as well as a
few statistics about the zone allocator and open and reclaimable zones
in /proc/*/mountstats.

This gives good insight into data fragmentation and data placement
success rate.

Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
Co-developed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/Makefile | 1 +
fs/xfs/xfs_super.c | 4 ++
fs/xfs/xfs_zone_alloc.h | 1 +
fs/xfs/xfs_zone_info.c | 120 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 126 insertions(+)
create mode 100644 fs/xfs/xfs_zone_info.c

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index e38838409271..5bf501cf8271 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -140,6 +140,7 @@ xfs-$(CONFIG_XFS_QUOTA) += xfs_dquot.o \
xfs-$(CONFIG_XFS_RT) += xfs_rtalloc.o \
xfs_zone_alloc.o \
xfs_zone_gc.o \
+ xfs_zone_info.o \
xfs_zone_space_resv.o

xfs-$(CONFIG_XFS_POSIX_ACL) += xfs_acl.o
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 47468623fdc6..df384c4de192 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1243,6 +1243,10 @@ xfs_fs_show_stats(
struct seq_file *m,
struct dentry *root)
{
+ struct xfs_mount *mp = XFS_M(root->d_sb);
+
+ if (xfs_has_zoned(mp) && IS_ENABLED(CONFIG_XFS_RT))
+ xfs_zoned_show_stats(m, mp);
return 0;
}

diff --git a/fs/xfs/xfs_zone_alloc.h b/fs/xfs/xfs_zone_alloc.h
index 44fa1594f73e..94ab32826c83 100644
--- a/fs/xfs/xfs_zone_alloc.h
+++ b/fs/xfs/xfs_zone_alloc.h
@@ -34,6 +34,7 @@ void xfs_mark_rtg_boundary(struct iomap_ioend *ioend);

uint64_t xfs_zoned_default_resblks(struct xfs_mount *mp,
enum xfs_free_counter ctr);
+void xfs_zoned_show_stats(struct seq_file *m, struct xfs_mount *mp);

#ifdef CONFIG_XFS_RT
int xfs_mount_zones(struct xfs_mount *mp);
diff --git a/fs/xfs/xfs_zone_info.c b/fs/xfs/xfs_zone_info.c
new file mode 100644
index 000000000000..689c9acb24d7
--- /dev/null
+++ b/fs/xfs/xfs_zone_info.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023-2024 Christoph Hellwig.
+ * Copyright (c) 2024, Western Digital Corporation or its affiliates.
+ */
+#include "xfs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_rtgroup.h"
+#include "xfs_zone_alloc.h"
+#include "xfs_zone_priv.h"
+
+static const char xfs_write_hint_shorthand[6][16] = {
+ "NOT_SET", "NONE", "SHORT", "MEDIUM", "LONG", "EXTREME"};
+
+static inline const char *
+xfs_write_hint_to_str(
+ uint8_t write_hint)
+{
+ if (write_hint > WRITE_LIFE_EXTREME)
+ return "UNKNOWN";
+ return xfs_write_hint_shorthand[write_hint];
+}
+
+static void
+xfs_show_open_zone(
+ struct seq_file *m,
+ struct xfs_open_zone *oz)
+{
+ seq_printf(m, "\t zone %d, wp %u, written %u, used %u, hint %s\n",
+ rtg_rgno(oz->oz_rtg),
+ oz->oz_write_pointer, oz->oz_written,
+ rtg_rmap(oz->oz_rtg)->i_used_blocks,
+ xfs_write_hint_to_str(oz->oz_write_hint));
+}
+
+#define XFS_USED_BUCKETS 10
+#define XFS_USED_BUCKET_PCT (100 / XFS_USED_BUCKETS)
+
+static unsigned int
+xfs_zone_to_bucket(
+ struct xfs_rtgroup *rtg)
+{
+ return div_u64(rtg_rmap(rtg)->i_used_blocks * XFS_USED_BUCKETS,
+ rtg->rtg_extents);
+}
+
+static void
+xfs_show_full_zone_used_distribution(
+ struct seq_file *m,
+ struct xfs_mount *mp)
+{
+ struct xfs_zone_info *zi = mp->m_zone_info;
+ XA_STATE (xas, &mp->m_groups[XG_TYPE_RTG].xa, 0);
+ unsigned int buckets[XFS_USED_BUCKETS] = {0};
+ unsigned int reclaimable = 0, full, i;
+ struct xfs_rtgroup *rtg;
+
+ lockdep_assert_held(&zi->zi_zone_list_lock);
+
+ rcu_read_lock();
+ xas_for_each_marked(&xas, rtg, ULONG_MAX, XFS_RTG_RECLAIMABLE) {
+ buckets[xfs_zone_to_bucket(rtg)]++;
+ reclaimable++;
+ }
+ rcu_read_unlock();
+
+ for (i = 0; i < XFS_USED_BUCKETS; i++)
+ seq_printf(m, "\t %2u..%2u%%: %u\n", i * XFS_USED_BUCKET_PCT,
+ (i + 1) * XFS_USED_BUCKET_PCT - 1, buckets[i]);
+
+ full = mp->m_sb.sb_rgcount;
+ if (zi->zi_open_gc_zone)
+ full--;
+ full -= zi->zi_nr_open_zones;
+ full -= atomic_read(&zi->zi_nr_free_zones);
+ full -= reclaimable;
+
+ seq_printf(m, "\t 100%%: %u\n", full);
+}
+
+void
+xfs_zoned_show_stats(
+ struct seq_file *m,
+ struct xfs_mount *mp)
+{
+ struct xfs_zone_info *zi = mp->m_zone_info;
+ struct xfs_open_zone *oz;
+
+ seq_puts(m, "\n");
+
+ seq_printf(m, "\tuser free blocks: %lld\n",
+ xfs_sum_freecounter(mp, XC_FREE_RTEXTENTS));
+ seq_printf(m, "\treserved free blocks: %lld\n",
+ mp->m_resblks[XC_FREE_RTEXTENTS].avail);
+ seq_printf(m, "\tuser available blocks: %lld\n",
+ xfs_sum_freecounter(mp, XC_FREE_RTAVAILABLE));
+ seq_printf(m, "\treserved available blocks: %lld\n",
+ mp->m_resblks[XC_FREE_RTAVAILABLE].avail);
+ seq_printf(m, "\treservations required: %d\n",
+ !list_empty_careful(&zi->zi_reclaim_reservations));
+ seq_printf(m, "\tGC required: %d\n",
+ xfs_zoned_need_gc(mp));
+
+ spin_lock(&zi->zi_zone_list_lock);
+ seq_printf(m, "\tfree zones: %d\n", atomic_read(&zi->zi_nr_free_zones));
+ seq_puts(m, "\topen zones:\n");
+ list_for_each_entry(oz, &zi->zi_open_zones, oz_entry)
+ xfs_show_open_zone(m, oz);
+ if (zi->zi_open_gc_zone) {
+ seq_puts(m, "\topen gc zone:\n");
+ xfs_show_open_zone(m, zi->zi_open_gc_zone);
+ }
+ seq_puts(m, "\tused blocks distribution (fully written zones):\n");
+ xfs_show_full_zone_used_distribution(m, mp);
+ spin_unlock(&zi->zi_zone_list_lock);
+}
--
2.45.2