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btrfs: keep track of discard reuse stats

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Keep track of how much we are discarding and how often we are reusing
with async discard. The discard_*_bytes values don't need any special
protection because the work item provides the single threaded access.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Dennis Zhou 2020-01-02 16:26:41 -05:00 committed by David Sterba
parent 5cb0724e1b
commit 9ddf648f9c
4 changed files with 58 additions and 0 deletions
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3
fs/btrfs/ctree.h
View file

@ -473,6 +473,9 @@ struct btrfs_discard_ctl {
unsigned long delay;
u32 iops_limit;
u32 kbps_limit;
u64 discard_extent_bytes;
u64 discard_bitmap_bytes;
atomic64_t discard_bytes_saved;
};
/* delayed seq elem */

5
fs/btrfs/discard.c
View file

@ -417,11 +417,13 @@ static void btrfs_discard_workfn(struct work_struct *work)
block_group->discard_cursor,
btrfs_block_group_end(block_group),
minlen, maxlen, true);
discard_ctl->discard_bitmap_bytes += trimmed;
} else {
btrfs_trim_block_group_extents(block_group, &trimmed,
block_group->discard_cursor,
btrfs_block_group_end(block_group),
minlen, true);
discard_ctl->discard_extent_bytes += trimmed;
}
discard_ctl->prev_discard = trimmed;
@ -626,6 +628,9 @@ void btrfs_discard_init(struct btrfs_fs_info *fs_info)
discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY_MSEC;
discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS;
discard_ctl->kbps_limit = 0;
discard_ctl->discard_extent_bytes = 0;
discard_ctl->discard_bitmap_bytes = 0;
atomic64_set(&discard_ctl->discard_bytes_saved, 0);
}
void btrfs_discard_cleanup(struct btrfs_fs_info *fs_info)

14
fs/btrfs/free-space-cache.c
View file

@ -2842,6 +2842,8 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
u64 *max_extent_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_discard_ctl *discard_ctl =
&block_group->fs_info->discard_ctl;
struct btrfs_free_space *entry = NULL;
u64 bytes_search = bytes + empty_size;
u64 ret = 0;
@ -2858,6 +2860,10 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
ret = offset;
if (entry->bitmap) {
bitmap_clear_bits(ctl, entry, offset, bytes);
if (!btrfs_free_space_trimmed(entry))
atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
if (!entry->bytes)
free_bitmap(ctl, entry);
} else {
@ -2866,6 +2872,9 @@ u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
align_gap = entry->offset;
align_gap_trim_state = entry->trim_state;
if (!btrfs_free_space_trimmed(entry))
atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
entry->offset = offset + bytes;
WARN_ON(entry->bytes < bytes + align_gap_len);
@ -2969,6 +2978,8 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
u64 min_start, u64 *max_extent_size)
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_discard_ctl *discard_ctl =
&block_group->fs_info->discard_ctl;
struct btrfs_free_space *entry = NULL;
struct rb_node *node;
u64 ret = 0;
@ -3033,6 +3044,9 @@ out:
spin_lock(&ctl->tree_lock);
if (!btrfs_free_space_trimmed(entry))
atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
ctl->free_space -= bytes;
if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;

36
fs/btrfs/sysfs.c
View file

@ -366,6 +366,39 @@ static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
}
BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
static ssize_t btrfs_discard_bitmap_bytes_show(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
{
struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
return snprintf(buf, PAGE_SIZE, "%lld\n",
fs_info->discard_ctl.discard_bitmap_bytes);
}
BTRFS_ATTR(discard, discard_bitmap_bytes, btrfs_discard_bitmap_bytes_show);
static ssize_t btrfs_discard_bytes_saved_show(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
{
struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
return snprintf(buf, PAGE_SIZE, "%lld\n",
atomic64_read(&fs_info->discard_ctl.discard_bytes_saved));
}
BTRFS_ATTR(discard, discard_bytes_saved, btrfs_discard_bytes_saved_show);
static ssize_t btrfs_discard_extent_bytes_show(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
{
struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
return snprintf(buf, PAGE_SIZE, "%lld\n",
fs_info->discard_ctl.discard_extent_bytes);
}
BTRFS_ATTR(discard, discard_extent_bytes, btrfs_discard_extent_bytes_show);
static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
@ -459,6 +492,9 @@ BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
static const struct attribute *discard_debug_attrs[] = {
BTRFS_ATTR_PTR(discard, discardable_bytes),
BTRFS_ATTR_PTR(discard, discardable_extents),
BTRFS_ATTR_PTR(discard, discard_bitmap_bytes),
BTRFS_ATTR_PTR(discard, discard_bytes_saved),
BTRFS_ATTR_PTR(discard, discard_extent_bytes),
BTRFS_ATTR_PTR(discard, iops_limit),
BTRFS_ATTR_PTR(discard, kbps_limit),
BTRFS_ATTR_PTR(discard, max_discard_size),