[PATCH 5.18 1024/1095] btrfs: make the bg_reclaim_threshold per-space info

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 19:28:28 EST


From: Josef Bacik <josef@xxxxxxxxxxxxxx>

[ Upstream commit bb5a098d9791f184899499531ff4411089e2a5e0 ]

For non-zoned file systems it's useful to have the auto reclaim feature,
however there are different use cases for non-zoned, for example we may
not want to reclaim metadata chunks ever, only data chunks. Move this
sysfs flag to per-space_info. This won't affect current users because
this tunable only ever did anything for zoned, and that is currently
hidden behind BTRFS_CONFIG_DEBUG.

Tested-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Signed-off-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
[ jth restore global bg_reclaim_threshold ]
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/btrfs/free-space-cache.c | 7 +++++--
fs/btrfs/space-info.c | 9 +++++++++
fs/btrfs/space-info.h | 6 ++++++
fs/btrfs/sysfs.c | 37 +++++++++++++++++++++++++++++++++++++
fs/btrfs/zoned.h | 6 +-----
5 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 01a408db5683..ef84bc5030cd 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2630,16 +2630,19 @@ int __btrfs_add_free_space(struct btrfs_block_group *block_group,
static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
u64 bytenr, u64 size, bool used)
{
- struct btrfs_fs_info *fs_info = block_group->fs_info;
+ struct btrfs_space_info *sinfo = block_group->space_info;
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
u64 offset = bytenr - block_group->start;
u64 to_free, to_unusable;
- const int bg_reclaim_threshold = READ_ONCE(fs_info->bg_reclaim_threshold);
+ int bg_reclaim_threshold = 0;
bool initial = (size == block_group->length);
u64 reclaimable_unusable;

WARN_ON(!initial && offset + size > block_group->zone_capacity);

+ if (!initial)
+ bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
+
spin_lock(&ctl->tree_lock);
if (!used)
to_free = size;
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 56a7c99fc03e..85608acb9557 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -181,6 +181,12 @@ void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
found->full = 0;
}

+/*
+ * Block groups with more than this value (percents) of unusable space will be
+ * scheduled for background reclaim.
+ */
+#define BTRFS_DEFAULT_ZONED_RECLAIM_THRESH (75)
+
static int create_space_info(struct btrfs_fs_info *info, u64 flags)
{

@@ -203,6 +209,9 @@ static int create_space_info(struct btrfs_fs_info *info, u64 flags)
INIT_LIST_HEAD(&space_info->priority_tickets);
space_info->clamp = 1;

+ if (btrfs_is_zoned(info))
+ space_info->bg_reclaim_threshold = BTRFS_DEFAULT_ZONED_RECLAIM_THRESH;
+
ret = btrfs_sysfs_add_space_info_type(info, space_info);
if (ret)
return ret;
diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index d841fed73492..a803e29bd781 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -24,6 +24,12 @@ struct btrfs_space_info {
the space info if we had an ENOSPC in the
allocator. */

+ /*
+ * Once a block group drops below this threshold (percents) we'll
+ * schedule it for reclaim.
+ */
+ int bg_reclaim_threshold;
+
int clamp; /* Used to scale our threshold for preemptive
flushing. The value is >> clamp, so turns
out to be a 2^clamp divisor. */
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index ba78ca5aabbb..43845cae0c74 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -722,6 +722,42 @@ SPACE_INFO_ATTR(bytes_zone_unusable);
SPACE_INFO_ATTR(disk_used);
SPACE_INFO_ATTR(disk_total);

+static ssize_t btrfs_sinfo_bg_reclaim_threshold_show(struct kobject *kobj,
+ struct kobj_attribute *a,
+ char *buf)
+{
+ struct btrfs_space_info *space_info = to_space_info(kobj);
+ ssize_t ret;
+
+ ret = sysfs_emit(buf, "%d\n", READ_ONCE(space_info->bg_reclaim_threshold));
+
+ return ret;
+}
+
+static ssize_t btrfs_sinfo_bg_reclaim_threshold_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t len)
+{
+ struct btrfs_space_info *space_info = to_space_info(kobj);
+ int thresh;
+ int ret;
+
+ ret = kstrtoint(buf, 10, &thresh);
+ if (ret)
+ return ret;
+
+ if (thresh != 0 && (thresh <= 50 || thresh > 100))
+ return -EINVAL;
+
+ WRITE_ONCE(space_info->bg_reclaim_threshold, thresh);
+
+ return len;
+}
+
+BTRFS_ATTR_RW(space_info, bg_reclaim_threshold,
+ btrfs_sinfo_bg_reclaim_threshold_show,
+ btrfs_sinfo_bg_reclaim_threshold_store);
+
/*
* Allocation information about block group types.
*
@@ -738,6 +774,7 @@ static struct attribute *space_info_attrs[] = {
BTRFS_ATTR_PTR(space_info, bytes_zone_unusable),
BTRFS_ATTR_PTR(space_info, disk_used),
BTRFS_ATTR_PTR(space_info, disk_total),
+ BTRFS_ATTR_PTR(space_info, bg_reclaim_threshold),
NULL,
};
ATTRIBUTE_GROUPS(space_info);
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index c424417e19bb..199b69670fa2 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -10,11 +10,7 @@
#include "block-group.h"
#include "btrfs_inode.h"

-/*
- * Block groups with more than this value (percents) of unusable space will be
- * scheduled for background reclaim.
- */
-#define BTRFS_DEFAULT_RECLAIM_THRESH 75
+#define BTRFS_DEFAULT_RECLAIM_THRESH (75)

struct btrfs_zoned_device_info {
/*
--
2.35.1