From: Nikolay Borisov <nborisov@suse.com> To: linux-btrfs@vger.kernel.org Cc: jeffm@suse.com, Nikolay Borisov <nborisov@suse.com> Subject: [PATCH 12/15] btrfs: Optimize unallocated chunks discard Date: Wed, 30 Jan 2019 16:50:59 +0200 Message-ID: <20190130145102.4708-13-nborisov@suse.com> (raw) In-Reply-To: <20190130145102.4708-1-nborisov@suse.com> Currently unallocated chunks are always trimmed. For example 2 consecutive trims on large storage would trim freespace twice irrespective of whether the space was actually allocated or not between those trims. Optimise this behavior by exploiting the newly introduced alloc_state tree of btrfs_device. A new CHUNK_TRIMMED bit is used to mark those unallocated chunks which have been trimmed and have not been allocated afterwards. On chunk allocation the respective underlying devices' physical space will have its CHUNK_TRIMMED flag cleared. This avoids submitting discards for space which hasn't been changed since the last time discard was issued. Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- fs/btrfs/extent-tree.c | 57 +++++++++++++++++++++++++++++++++++++++++- fs/btrfs/extent_io.h | 8 +++++- fs/btrfs/extent_map.c | 4 ++- 3 files changed, 66 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 610bed028511..f5005ef39f98 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -11127,6 +11127,54 @@ int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info, return unpin_extent_range(fs_info, start, end, false); } +static bool should_skip_trim(struct btrfs_device *device, u64 *start, u64 *len) +{ + u64 trimmed_start = 0, trimmed_end = 0; + u64 end = *start + *len - 1; + + if (!find_first_extent_bit(&device->alloc_state, *start, &trimmed_start, + &trimmed_end, CHUNK_TRIMMED, NULL)) { + u64 trimmed_len = trimmed_end - trimmed_start + 1; + + if (*start < trimmed_start) { + if (in_range(end, trimmed_start, trimmed_len) || + end > trimmed_end) { + /* + * start|------|end + * ts|--|trimmed_len + * OR + * start|-----|end + * ts|-----|trimmed_len + */ + *len = trimmed_start - *start; + return false; + } else if (end < trimmed_start) { + /* + * start|------|end + * ts|--|trimmed_len + */ + return false; + } + } else if (in_range(*start, trimmed_start, trimmed_len)) { + if (in_range(end, trimmed_start, trimmed_len)) { + /* + * start|------|end + * ts|----------|trimmed_len + */ + return true; + } else { + /* + * start|-----------|end + * ts|----------|trimmed_len + */ + *start = trimmed_end + 1; + *len = end - *start + 1; + return false; + } + } + } + return false; +} /* * It used to be that old block groups would be left around forever. * Iterating over them would be enough to trim unused space. Since we @@ -11197,7 +11245,14 @@ static int btrfs_trim_free_extents(struct btrfs_device *device, start = max(range->start, start); len = min(range->len, len); - ret = btrfs_issue_discard(device->bdev, start, len, &bytes); + if (!should_skip_trim(device, &start, &len)) { + ret = btrfs_issue_discard(device->bdev, start, len, + &bytes); + if (!ret) + set_extent_bits(&device->alloc_state, start, + start + bytes - 1, + CHUNK_TRIMMED); + } mutex_unlock(&fs_info->chunk_mutex); if (ret) diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index d4227e40c8ee..d238efd628cf 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -30,8 +30,14 @@ #define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING) -/* Redefined bits above which are used only in the device allocation tree */ +/* + * Redefined bits above which are used only in the device allocation tree, + * shouldn't be using EXTENT_IOBITS(EXTENT_LOCKED/EXTENT_WRITEBACK) / + * EXTENT_BOUNDARY / EXTENT_CLEAR_META_RESV / EXTENT_CLEAR_DATA_RESV because + * they have special meaning to the bit manipulation functions + */ #define CHUNK_ALLOCATED EXTENT_DIRTY +#define CHUNK_TRIMMED EXTENT_DEFRAG /* * flags for bio submission. The high bits indicate the compression diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 0820f6fcf3a6..9e8c0904f623 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -389,8 +389,10 @@ int add_extent_mapping(struct extent_map_tree *tree, goto out; setup_extent_mapping(tree, em, modified); - if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) + if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) { extent_map_device_set_bits(em, CHUNK_ALLOCATED); + extent_map_device_clear_bits(em, CHUNK_TRIMMED); + } out: return ret; } -- 2.17.1
next prev parent reply index Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-30 14:50 [PATCH 00/15] Improvements to fitrim Nikolay Borisov 2019-01-30 14:50 ` [PATCH 01/15] btrfs: Honour FITRIM range constraints during free space trim Nikolay Borisov 2019-01-31 15:21 ` David Sterba 2019-01-31 15:35 ` Nikolay Borisov 2019-01-31 15:48 ` David Sterba 2019-01-31 19:30 ` Jeff Mahoney 2019-01-31 21:45 ` Nikolay Borisov 2019-01-30 14:50 ` [PATCH 02/15] btrfs: Make WARN_ON in a canonical form Nikolay Borisov 2019-01-31 15:22 ` David Sterba 2019-02-04 13:12 ` Johannes Thumshirn 2019-01-30 14:50 ` [PATCH 03/15] btrfs: Remove EXTENT_FIRST_DELALLOC bit Nikolay Borisov 2019-01-31 15:23 ` David Sterba 2019-02-04 13:15 ` Johannes Thumshirn 2019-01-30 14:50 ` [PATCH 04/15] btrfs: combine device update operations during transaction commit Nikolay Borisov 2019-02-04 13:25 ` Johannes Thumshirn 2019-02-04 14:48 ` Nikolay Borisov 2019-02-05 9:21 ` Johannes Thumshirn 2019-01-30 14:50 ` [PATCH 05/15] btrfs: Handle pending/pinned chunks before blockgroup relocation during device shrink Nikolay Borisov 2019-02-04 13:29 ` Johannes Thumshirn 2019-01-30 14:50 ` [PATCH 06/15] btrfs: Rename and export clear_btree_io_tree Nikolay Borisov 2019-02-04 13:31 ` Johannes Thumshirn 2019-01-30 14:50 ` [PATCH 07/15] btrfs: Populate ->orig_block_len during read_one_chunk Nikolay Borisov 2019-01-30 14:50 ` [PATCH 08/15] btrfs: Introduce new bits for device allocation tree Nikolay Borisov 2019-01-30 14:50 ` [PATCH 09/15] btrfs: replace pending/pinned chunks lists with io tree Nikolay Borisov 2019-01-30 14:50 ` [PATCH 10/15] btrfs: Remove 'trans' argument from find_free_dev_extent(_start) Nikolay Borisov 2019-02-04 14:36 ` Johannes Thumshirn 2019-01-30 14:50 ` [PATCH 11/15] btrfs: Factor out in_range macro Nikolay Borisov 2019-02-04 13:57 ` Johannes Thumshirn 2019-01-30 14:50 ` Nikolay Borisov [this message] 2019-01-30 14:51 ` [PATCH 13/15] btrfs: Fix gross misnaming Nikolay Borisov 2019-01-30 14:51 ` [PATCH 14/15] btrfs: Implement find_first_clear_extent_bit Nikolay Borisov 2019-02-04 14:04 ` Johannes Thumshirn 2019-02-04 16:57 ` Nikolay Borisov 2019-01-30 14:51 ` [PATCH 15/15] btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit Nikolay Borisov 2019-01-31 15:38 ` [PATCH v2] " Nikolay Borisov 2019-01-31 15:41 ` [PATCH v3] " Nikolay Borisov
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