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: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 438043a..db90bea 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -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)