@@ -470,6 +470,7 @@ struct btrfs_discard_ctl {
u64 prev_discard;
atomic_t discardable_extents;
atomic64_t discardable_bytes;
+ u64 max_discard_size;
u32 delay;
u32 iops_limit;
u64 bps_limit;
@@ -529,6 +529,7 @@ 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_MAX_SIZE;
discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY;
discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS;
discard_ctl->bps_limit = 0;
@@ -3407,6 +3407,8 @@ 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;
@@ -3415,6 +3417,7 @@ static int trim_no_bitmap(struct btrfs_block_group *block_group,
u64 extent_bytes;
enum btrfs_trim_state extent_trim_state;
u64 bytes;
+ u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
while (start < end) {
struct btrfs_trim_range trim_entry;
@@ -3452,11 +3455,10 @@ 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 = 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 = 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);
@@ -3565,12 +3567,15 @@ 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);
+ u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
while (offset < end) {
bool next_bitmap = false;
@@ -3640,8 +3645,8 @@ 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)
@@ -404,6 +404,36 @@ static ssize_t btrfs_discard_bps_limit_store(struct kobject *kobj,
BTRFS_ATTR_RW(discard, bps_limit, btrfs_discard_bps_limit_show,
btrfs_discard_bps_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 ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
@@ -429,6 +459,7 @@ BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
static const struct attribute *discard_debug_attrs[] = {
BTRFS_ATTR_PTR(discard, iops_limit),
BTRFS_ATTR_PTR(discard, bps_limit),
+ BTRFS_ATTR_PTR(discard, max_discard_size),
BTRFS_ATTR_PTR(discard, discardable_extents),
BTRFS_ATTR_PTR(discard, discardable_bytes),
NULL,
Expose max_discard_size as a tunable via sysfs. Signed-off-by: Dennis Zhou <dennis@kernel.org> --- fs/btrfs/ctree.h | 1 + fs/btrfs/discard.c | 1 + fs/btrfs/free-space-cache.c | 19 ++++++++++++------- fs/btrfs/sysfs.c | 31 +++++++++++++++++++++++++++++++ 4 files changed, 45 insertions(+), 7 deletions(-)