Commit 19b2a2c7 authored by Dennis Zhou's avatar Dennis Zhou Committed by David Sterba
Browse files

btrfs: make max async discard size tunable 



Expose max_discard_size as a tunable via sysfs and switch the current
fixed maximum to the default value.

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 4aa9ad52

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -469,6 +469,7 @@ struct btrfs_discard_ctl { 
	u64 prev_discard;

	atomic_t discardable_extents;

	atomic64_t discardable_bytes;

	u64 max_discard_size;

	unsigned long delay;

	u32 iops_limit;

	u32 kbps_limit;

fs/btrfs/discard.c

+1 −0
Original line number Diff line number Diff line
@@ -527,6 +527,7 @@ void btrfs_discard_init(struct btrfs_fs_info *fs_info) 
	discard_ctl->prev_discard = 0;

	atomic_set(&discard_ctl->discardable_extents, 0);

	atomic64_set(&discard_ctl->discardable_bytes, 0);

	discard_ctl->max_discard_size = BTRFS_ASYNC_DISCARD_DEFAULT_MAX_SIZE;

	discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY_MSEC;

	discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS;

	discard_ctl->kbps_limit = 0;

fs/btrfs/discard.h

+1 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ struct btrfs_discard_ctl; 
struct btrfs_block_group;



/* Discard size limits */

#define BTRFS_ASYNC_DISCARD_MAX_SIZE	(SZ_64M)

#define BTRFS_ASYNC_DISCARD_DEFAULT_MAX_SIZE		(SZ_64M)



/* Work operations */

void btrfs_discard_cancel_work(struct btrfs_discard_ctl *discard_ctl,

fs/btrfs/free-space-cache.c

+13 −7
Original line number Diff line number Diff line
@@ -3428,6 +3428,8 @@ static int trim_no_bitmap(struct btrfs_block_group *block_group, 
			  u64 *total_trimmed, u64 start, u64 end, u64 minlen,

			  bool async)

{

	struct btrfs_discard_ctl *discard_ctl =

					&block_group->fs_info->discard_ctl;

	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;

	struct btrfs_free_space *entry;

	struct rb_node *node;
@@ -3436,6 +3438,7 @@ static int trim_no_bitmap(struct btrfs_block_group *block_group, 
	u64 extent_bytes;

	enum btrfs_trim_state extent_trim_state;

	u64 bytes;

	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);



	while (start < end) {

		struct btrfs_trim_range trim_entry;
@@ -3475,11 +3478,11 @@ static int trim_no_bitmap(struct btrfs_block_group *block_group, 
				goto next;

			}

			unlink_free_space(ctl, entry);

			if (bytes > BTRFS_ASYNC_DISCARD_MAX_SIZE) {

				bytes = BTRFS_ASYNC_DISCARD_MAX_SIZE;

				extent_bytes = BTRFS_ASYNC_DISCARD_MAX_SIZE;

				entry->offset += BTRFS_ASYNC_DISCARD_MAX_SIZE;

				entry->bytes -= BTRFS_ASYNC_DISCARD_MAX_SIZE;

			if (max_discard_size && bytes > max_discard_size) {

				bytes = max_discard_size;

				extent_bytes = max_discard_size;

				entry->offset += max_discard_size;

				entry->bytes -= max_discard_size;

				link_free_space(ctl, entry);

			} else {

				kmem_cache_free(btrfs_free_space_cachep, entry);
@@ -3584,12 +3587,15 @@ static int trim_bitmaps(struct btrfs_block_group *block_group, 
			u64 *total_trimmed, u64 start, u64 end, u64 minlen,

			bool async)

{

	struct btrfs_discard_ctl *discard_ctl =

					&block_group->fs_info->discard_ctl;

	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;

	struct btrfs_free_space *entry;

	int ret = 0;

	int ret2;

	u64 bytes;

	u64 offset = offset_to_bitmap(ctl, start);

	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);



	while (offset < end) {

		bool next_bitmap = false;
@@ -3659,8 +3665,8 @@ static int trim_bitmaps(struct btrfs_block_group *block_group, 
			goto next;

		}



		if (async && bytes > BTRFS_ASYNC_DISCARD_MAX_SIZE)

			bytes = BTRFS_ASYNC_DISCARD_MAX_SIZE;

		if (async && max_discard_size && bytes > max_discard_size)

			bytes = max_discard_size;



		bitmap_clear_bits(ctl, entry, start, bytes);

		if (entry->bytes == 0)

fs/btrfs/sysfs.c

+31 −0
Original line number Diff line number Diff line
@@ -426,11 +426,42 @@ static ssize_t btrfs_discard_kbps_limit_store(struct kobject *kobj, 
BTRFS_ATTR_RW(discard, kbps_limit, btrfs_discard_kbps_limit_show,

	      btrfs_discard_kbps_limit_store);



static ssize_t btrfs_discard_max_discard_size_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, "%llu\n",

			READ_ONCE(fs_info->discard_ctl.max_discard_size));

}



static ssize_t btrfs_discard_max_discard_size_store(struct kobject *kobj,

						    struct kobj_attribute *a,

						    const char *buf, size_t len)

{

	struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);

	struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;

	u64 max_discard_size;

	int ret;



	ret = kstrtou64(buf, 10, &max_discard_size);

	if (ret)

		return -EINVAL;



	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);



	return len;

}

BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,

	      btrfs_discard_max_discard_size_store);



static const struct attribute *discard_debug_attrs[] = {

	BTRFS_ATTR_PTR(discard, discardable_bytes),

	BTRFS_ATTR_PTR(discard, discardable_extents),

	BTRFS_ATTR_PTR(discard, iops_limit),

	BTRFS_ATTR_PTR(discard, kbps_limit),

	BTRFS_ATTR_PTR(discard, max_discard_size),

	NULL,

};