Commit 9ddf648f authored by Dennis Zhou's avatar Dennis Zhou Committed by David Sterba
Browse files

btrfs: keep track of discard reuse stats 



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: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarDennis Zhou <dennis@kernel.org>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 5cb0724e

fs/btrfs/ctree.h

+3 −0
Original line number Diff line number Diff line
@@ -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 */

fs/btrfs/discard.c

+5 −0
Original line number Diff line number Diff line
@@ -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)

fs/btrfs/free-space-cache.c

+14 −0
Original line number Diff line number Diff line
@@ -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;

fs/btrfs/sysfs.c

+36 −0
Original line number Diff line number Diff line
@@ -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),

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