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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-07 10:55:36 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-07 10:55:36 -0700 |
commit | 3021112598d2b722eee54d8a662fea2089abbdbc (patch) | |
tree | 640c5f7b1d8ece378e3e67bd3c401c80b40ecea8 /Documentation/filesystems | |
parent | 0af9fb63915cf5ebb47b5c9ff16526b47545baf5 (diff) | |
parent | 48b230a583965d33c32b4e3c29a1e5e15d7e55de (diff) | |
download | op-kernel-dev-3021112598d2b722eee54d8a662fea2089abbdbc.zip op-kernel-dev-3021112598d2b722eee54d8a662fea2089abbdbc.tar.gz |
Merge tag 'for-f2fs-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"This patch-set includes the following major enhancement patches.
- introduce large directory support
- introduce f2fs_issue_flush to merge redundant flush commands
- merge write IOs as much as possible aligned to the segment
- add sysfs entries to tune the f2fs configuration
- use radix_tree for the free_nid_list to reduce in-memory operations
- remove costly bit operations in f2fs_find_entry
- enhance the readahead flow for CP/NAT/SIT/SSA blocks
The other bug fixes are as follows:
- recover xattr node blocks correctly after sudden-power-cut
- fix to calculate the maximum number of node ids
- enhance to handle many error cases
And, there are a bunch of cleanups"
* tag 'for-f2fs-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (62 commits)
f2fs: fix wrong statistics of inline data
f2fs: check the acl's validity before setting
f2fs: introduce f2fs_issue_flush to avoid redundant flush issue
f2fs: fix to cover io->bio with io_rwsem
f2fs: fix error path when fail to read inline data
f2fs: use list_for_each_entry{_safe} for simplyfying code
f2fs: avoid free slab cache under spinlock
f2fs: avoid unneeded lookup when xattr name length is too long
f2fs: avoid unnecessary bio submit when wait page writeback
f2fs: return -EIO when node id is not matched
f2fs: avoid RECLAIM_FS-ON-W warning
f2fs: skip unnecessary node writes during fsync
f2fs: introduce fi->i_sem to protect fi's info
f2fs: change reclaim rate in percentage
f2fs: add missing documentation for dir_level
f2fs: remove unnecessary threshold
f2fs: throttle the memory footprint with a sysfs entry
f2fs: avoid to drop nat entries due to the negative nr_shrink
f2fs: call f2fs_wait_on_page_writeback instead of native function
f2fs: introduce nr_pages_to_write for segment alignment
...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r-- | Documentation/filesystems/f2fs.txt | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt index b8d2849..25311e11 100644 --- a/Documentation/filesystems/f2fs.txt +++ b/Documentation/filesystems/f2fs.txt @@ -122,6 +122,10 @@ disable_ext_identify Disable the extension list configured by mkfs, so f2fs inline_xattr Enable the inline xattrs feature. inline_data Enable the inline data feature: New created small(<~3.4k) files can be written into inode block. +flush_merge Merge concurrent cache_flush commands as much as possible + to eliminate redundant command issues. If the underlying + device handles the cache_flush command relatively slowly, + recommend to enable this option. ================================================================================ DEBUGFS ENTRIES @@ -169,9 +173,11 @@ Files in /sys/fs/f2fs/<devname> reclaim_segments This parameter controls the number of prefree segments to be reclaimed. If the number of prefree - segments is larger than this number, f2fs tries to - conduct checkpoint to reclaim the prefree segments - to free segments. By default, 100 segments, 200MB. + segments is larger than the number of segments + in the proportion to the percentage over total + volume size, f2fs tries to conduct checkpoint to + reclaim the prefree segments to free segments. + By default, 5% over total # of segments. max_small_discards This parameter controls the number of discard commands that consist small blocks less than 2MB. @@ -195,6 +201,17 @@ Files in /sys/fs/f2fs/<devname> cleaning operations. The default value is 4096 which covers 8GB block address range. + dir_level This parameter controls the directory level to + support large directory. If a directory has a + number of files, it can reduce the file lookup + latency by increasing this dir_level value. + Otherwise, it needs to decrease this value to + reduce the space overhead. The default value is 0. + + ram_thresh This parameter controls the memory footprint used + by free nids and cached nat entries. By default, + 10 is set, which indicates 10 MB / 1 GB RAM. + ================================================================================ USAGE ================================================================================ @@ -444,9 +461,11 @@ The number of blocks and buckets are determined by, # of blocks in level #n = | `- 4, Otherwise - ,- 2^n, if n < MAX_DIR_HASH_DEPTH / 2, + ,- 2^ (n + dir_level), + | if n < MAX_DIR_HASH_DEPTH / 2, # of buckets in level #n = | - `- 2^((MAX_DIR_HASH_DEPTH / 2) - 1), Otherwise + `- 2^((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1), + Otherwise When F2FS finds a file name in a directory, at first a hash value of the file name is calculated. Then, F2FS scans the hash table in level #0 to find the |