diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-09 13:27:51 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-09 13:27:51 -0700 |
commit | 66ba772ee3119849fcdd8ac9766c6c25ede4a982 (patch) | |
tree | 5d7b174b1a34f331b96ff1b55e6a78e4bf74c883 /fs/btrfs/compression.c | |
parent | 126e76ffbf78d9e948b641aadb265d16c57f5a3d (diff) | |
parent | db95c876c568cef951fbbd4c0118cb5386e4bb99 (diff) |
Merge branch 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The changes range through all types: cleanups, core chagnes, sanity
checks, fixes, other user visible changes, detailed list below:
- deprecated: user transaction ioctl
- mount option ssd does not change allocation alignments
- degraded read-write mount is allowed if all the raid profile
constraints are met, now based on more accurate check
- defrag: do not reset compression afterwards; the NOCOMPRESS flag
can be now overriden by defrag
- prep work for better extent reference tracking (related to the
qgroup slowness with balance)
- prep work for compression heuristics
- memory allocation reductions (may help latencies on a loaded
system)
- better accounting for io waiting states
- error handling improvements (removed BUGs)
- added more sanity checks for shared refs
- fix readdir vs pagefault deadlock under some circumstances
- fix for 'no-hole' mode, certain combination of compressed and
inline extents
- send: fix emission of invalid clone operations
- fixup file mode if setting acls fail
- more fixes from fuzzing
- oher cleanups"
* 'for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (104 commits)
btrfs: submit superblock io with REQ_META and REQ_PRIO
btrfs: remove unnecessary memory barrier in btrfs_direct_IO
btrfs: remove superfluous chunk_tree argument from btrfs_alloc_dev_extent
btrfs: Remove chunk_objectid parameter of btrfs_alloc_dev_extent
btrfs: pass fs_info to btrfs_del_root instead of tree_root
Btrfs: add one more sanity check for shared ref type
Btrfs: remove BUG_ON in __add_tree_block
Btrfs: remove BUG() in add_data_reference
Btrfs: remove BUG() in print_extent_item
Btrfs: remove BUG() in btrfs_extent_inline_ref_size
Btrfs: convert to use btrfs_get_extent_inline_ref_type
Btrfs: add a helper to retrive extent inline ref type
btrfs: scrub: simplify scrub worker initialization
btrfs: scrub: clean up division in scrub_find_csum
btrfs: scrub: clean up division in __scrub_mark_bitmap
btrfs: scrub: use bool for flush_all_writes
btrfs: preserve i_mode if __btrfs_set_acl() fails
btrfs: Remove extraneous chunk_objectid variable
btrfs: Remove chunk_objectid argument from btrfs_make_block_group
btrfs: Remove extra parentheses from condition in copy_items()
...
Diffstat (limited to 'fs/btrfs/compression.c')
-rw-r--r-- | fs/btrfs/compression.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index d2ef9ac2a630..883ecc58fd0d 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -825,7 +825,7 @@ static void free_workspace(int type, struct list_head *workspace) int *free_ws = &btrfs_comp_ws[idx].free_ws; spin_lock(ws_lock); - if (*free_ws < num_online_cpus()) { + if (*free_ws <= num_online_cpus()) { list_add(workspace, idle_ws); (*free_ws)++; spin_unlock(ws_lock); @@ -1047,3 +1047,36 @@ int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, return 1; } + +/* + * Compression heuristic. + * + * For now is's a naive and optimistic 'return true', we'll extend the logic to + * quickly (compared to direct compression) detect data characteristics + * (compressible/uncompressible) to avoid wasting CPU time on uncompressible + * data. + * + * The following types of analysis can be performed: + * - detect mostly zero data + * - detect data with low "byte set" size (text, etc) + * - detect data with low/high "core byte" set + * + * Return non-zero if the compression should be done, 0 otherwise. + */ +int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) +{ + u64 index = start >> PAGE_SHIFT; + u64 end_index = end >> PAGE_SHIFT; + struct page *page; + int ret = 1; + + while (index <= end_index) { + page = find_get_page(inode->i_mapping, index); + kmap(page); + kunmap(page); + put_page(page); + index++; + } + + return ret; +} |