From 19b2a2c71979f849cadc33af3577f739cc95e1f0 Mon Sep 17 00:00:00 2001 From: Dennis Zhou Date: Thu, 2 Jan 2020 16:26:38 -0500 Subject: 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 Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.h | 1 + fs/btrfs/discard.c | 1 + fs/btrfs/discard.h | 2 +- fs/btrfs/free-space-cache.c | 20 +++++++++++++------- fs/btrfs/sysfs.c | 31 +++++++++++++++++++++++++++++++ 5 files changed, 47 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index f58b1cfeeca6..fa6c95fdf5c6 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -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; diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c index 565931f9a9aa..5fdd82c356a4 100644 --- a/fs/btrfs/discard.c +++ b/fs/btrfs/discard.c @@ -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; diff --git a/fs/btrfs/discard.h b/fs/btrfs/discard.h index 562c60fab77a..f9445ee5dcc3 100644 --- a/fs/btrfs/discard.h +++ b/fs/btrfs/discard.h @@ -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, diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 438043aab6fb..db90bea30a8d 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) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 0168bc12875e..eac0155bf8c7 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -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, }; -- cgit v1.2.3