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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>
This commit is contained in:
Dennis Zhou 2020-01-02 16:26:38 -05:00 committed by David Sterba
parent 4aa9ad5203
commit 19b2a2c719
5 changed files with 47 additions and 8 deletions
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1
fs/btrfs/ctree.h
View File

@ -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;

1
fs/btrfs/discard.c
View File

@ -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;

2
fs/btrfs/discard.h
View File

@ -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,

20
fs/btrfs/free-space-cache.c
View File

@ -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)

31
fs/btrfs/sysfs.c
View File

@ -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,
};